BU-808: How to Prolong Lithium-based Batteries. 18650 rechargeable battery 5000mah

BU-808: How to Prolong Lithium-based Batteries

Battery research is focusing on lithium chemistries so much that one could imagine that the battery future lies solely in lithium. There are good reasons to be optimistic as lithium-ion is, in many ways, superior to other chemistries. Applications are growing and are encroaching into markets that previously were solidly held by lead acid, such as standby and load leveling. Many satellites are also powered by Li-ion.

Lithium-ion has not yet fully matured and is still improving. Notable advancements have been made in longevity and safety while the capacity is increasing incrementally. Today, Li-ion meets the expectations of most consumer devices but applications for the EV need further development before this power source will become the accepted norm.

As battery care-giver, you have choices in how to prolong battery life. Each battery system has unique needs in terms of charging speed, depth of discharge, loading and exposure to adverse temperature. Check what causes capacity loss, how does rising internal resistance affect performance, what does elevated self-discharge do and how low can a battery be discharged? You may also be interested in the fundamentals of battery testing.

What Causes Lithium-ion to Age?

The lithium-ion battery works on ion movement between the positive and negative electrodes. In theory such a mechanism should work forever, but cycling, elevated temperature and aging decrease the performance over time. Manufacturers take a conservative approach and specify the life of Li-ion in most consumer products as being between 300 and 500 discharge/charge cycles.

Evaluating battery life on counting cycles is not conclusive because a discharge may vary in depth and there are no clearly defined standards of what constitutes a cycle(See BU-501: Basics About Discharging). In lieu of cycle count, some device manufacturers suggest battery replacement on a date stamp, but this method does not take usage into account. A battery may fail within the allotted time due to heavy use or unfavorable temperature conditions; however, most packs last considerably longer than what the stamp indicates.

The performance of a battery is measured in capacity, a leading health indicator. Internal resistance and self-discharge also play roles, but these are less significant in predicting the end of battery life with modern Li-ion.

Figure 1 illustrates the capacity drop of 11 Li-polymer batteries that have been cycled at a Cadex laboratory. The 1,500mAh pouch cells for mobile phones were first charged at a current of 1,500mA (1C) to 4.20V/cell and then allowed to saturate to 0.05C (75mA) as part of the full charge saturation. The batteries were then discharged at 1,500mA to 3.0V/cell, and the cycle was repeated. The expected capacity loss of Li-ion batteries was uniform over the delivered 250 cycles and the batteries performed as expected.

Eleven new Li-ion were tested on a Cadex C7400 battery analyzer. All packs started at a capacity of 88–94% and decreased to 73–84% after 250 full discharge cycles. The 1500mAh pouch packs are used in mobile phones.

Although a battery should deliver 100 percent capacity during the first year of service, it is common to see lower than specified capacities, and shelf life may contribute to this loss. In addition, manufacturers tend to overrate their batteries, knowing that very few users will do spot-checks and complain if low. Not having to match single cells in mobile phones and tablets, as is required in multi-cell packs, opens the floodgates for a much broader performance acceptance. Cells with lower capacities may slip through cracks without the consumer knowing.

Similar to a mechanical device that wears out faster with heavy use, the depth of discharge (DoD) determines the cycle count of the battery. The smaller the discharge (low DoD), the longer the battery will last. If at all possible, avoid full discharges and charge the battery more often between uses. Partial discharge on Li-ion is fine. There is no memory and the battery does not need periodic full discharge cycles to prolong life. The exception may be a periodic calibration of the fuel gauge on a Smart battery or intelligent device(See BU-603: How to Calibrate a “Smart” Battery)

The following tables indicate stress related capacity losses on cobalt-based lithium-ion. The voltages of lithium iron phosphate and lithium titanate are lower and do not apply to the voltage references given.

Note: Tables 2, 3 and 4 indicate general aging trends of common cobalt-based Li-ion batteries on depth-of-discharge, temperature and charge levels, Table 6 further looks at capacity loss when operating within given and discharge bandwidths. The tables do not address ultra-fast charging and high load discharges that will shorten battery life. No all batteries behave the same.

Table 2 estimates the number of discharge/charge cycles Li-ion can deliver at various DoD levels before the battery capacity drops to 70 percent. DoD constitutes a full charge followed by a discharge to the indicated state-of-charge (SoC) level in the table.

100% DoD is a full cycle; 10% is very brief. Cycling in mid-state-of-charge would have best longevity.

Lithium-ion suffers from stress when exposed to heat, so does keeping a cell at a high charge voltage. A battery dwelling above 30°C (86°F) is considered elevated temperature and for most Li-ion a voltage above 4.10V/cell is deemed as high voltage. Exposing the battery to high temperature and dwelling in a full state-of-charge for an extended time can be more stressful than cycling. Table 3 demonstrates capacity loss as a function of temperature and SoC.

Temperature 40% Charge 100% Charge
0°C 98% (after 1 year) 94% (after 1 year)
25°C 96% (after 1 year) 80% (after 1 year)
40°C 85% (after 1 year) 65% (after 1 year)
60°C 75% (after 1 year) 60% (after 3 months)

Table 3: Estimated recoverable capacity when storing Li-ion for one year at various temperaturesElevated temperature hastens permanent capacity loss. Not all Li-ion systems behave the same.

Most Li-ions charge to 4.20V/cell, and every reduction in peak charge voltage of 0.10V/cell is said to double the cycle life. For example, a lithium-ion cell charged to 4.20V/cell typically delivers 300–500 cycles. If charged to only 4.10V/cell, the life can be prolonged to 600–1,000 cycles; 4.0V/cell should deliver 1,200–2,000 and 3.90V/cell should provide 2,400–4,000 cycles.

On the negative side, a lower peak charge voltage reduces the capacity the battery stores. As a simple guideline, every 70mV reduction in charge voltage lowers the overall capacity by 10 percent. Applying the peak charge voltage on a subsequent charge will restore the full capacity.

In terms of longevity, the optimal charge voltage is 3.92V/cell. Battery experts believe that this threshold eliminates all voltage-related stresses; going lower may not gain further benefits but induce other symptoms(See BU-808b: What causes Li-ion to die?) Table 4 summarizes the capacity as a function of charge levels. (All values are estimated; Energy Cells with higher voltage thresholds may deviate.)

Charge Level (V/cell) Discharge Cycles Available Stored Energy
[4.30] [150–250] [110–115%]
4.25 200–350 105–110%
4.20 300–500 100%
4.15 400–700 90–95%
4.10 600–1,000 85–90%
4.05 850–1,500 80–85%
4.00 1,200–2,000 70–75%
3.90 2,400–4,000 60–65%
3.80 See note 35–40%
3.70 See note 30% and less

Table 4: Discharge cycles and capacity as a function of charge voltage limit

Every 0.10V drop below 4.20V/cell doubles the cycle but holds less capacity. Raising the voltage above 4.20V/cell would shorten the life. The readings reflect regular Li-ion charging to 4.20V/cell.

Guideline: Every 70mV drop in charge voltage lowers the usable capacity by about 10%.Note: Partial charging negates the benefit of Li-ion in terms of high specific energy.

Similar life cycles apply for batteries with different voltage levels on full charge. Based on a new battery with 100% capacity when charged to the full voltage.

Experiment: Chalmers University of Technology, Sweden, reports that using a reduced charge level of 50% SOC increases the lifetime expectancy of the vehicle Li-ion battery by 44–130%.

Most chargers for mobile phones, laptops, tablets and digital cameras charge Li-ion to 4.20V/cell. This allows maximum capacity, because the consumer wants nothing less than optimal runtime. Industry, on the other hand, is more concerned about longevity and may choose lower voltage thresholds. Satellites and electric vehicles are such examples.

For safety reasons, many lithium-ions cannot exceed 4.20V/cell. (Some NMC are the exception.) While a higher voltage boosts capacity, exceeding the voltage shortens service life and compromises safety. Figure 5 demonstrates cycle count as a function of charge voltage. At 4.35V, the cycle count of a regular Li-ion is cut in half.

Besides selecting the best-suited voltage thresholds for a given application, a regular Li-ion should not remain at the high-voltage ceiling of 4.20V/cell for an extended time. The Li-ion charger turns off the charge current and the battery voltage reverts to a more natural level. This is like relaxing the muscles after a strenuous exercise(See BU-409: Charging Lithium-ion)

Figure 6 illustrates dynamic stress tests (DST) reflecting capacity loss when cycling Li-ion at various charge and discharge bandwidths. The largest capacity loss occurs when discharging a fully charged Li-ion to 25 percent SoC (black); the loss would be higher if fully discharged. Cycling between 85 and 25 percent (green) provides a longer service life than charging to 100 percent and discharging to 50 percent (dark blue). The smallest capacity loss is attained by charging Li-ion to 75 percent and discharging to 65 percent. This, however, does not fully utilize the battery. High voltages and exposure to elevated temperature is said to degrade the battery quicker than cycling under normal condition. (Nissan Leaf case)

  • Case 1: 75–65% SoC offers longest cycle life but delivers only 90,000 energy units (EU). Utilizes 10% of battery.
  • Case 2: 75–25% SoC has 3,000 cycles (to 90% capacity) and delivers 150,000 EU. Utilizes 50% of battery. (EV battery, new.)
  • Case 3: 85–25% SoC has 2,000 cycles. Delivers 120,000 EU. Uses 60% of battery.
  • Case 4: 100–25% SoC; long runtime with 75% use of battery. Has short life. (Mobile phone, drone, etc.)

Discrepancies exist between Table 2 and Figure 6 on cycle count. No clear explanations are available other than assuming differences in battery quality and test methods. Variances between low-cost consumer and durable industrial grades may also play a role. Capacity retention will decline more rapidly at elevated temperatures than at 20ºC.

Only a full cycle provides the specified energy of a battery. With a modern Energy Cell, this is about 250Wh/kg, but the cycle life will be compromised. All being linear, the life-prolonging mid-range of 85-25 percent reduces the energy to 60 percent and this equates to moderating the specific energy density from 250Wh/kg to 150Wh/kg. Mobile phones are consumer goods that utilize the full energy of a battery. Industrial devices, such as the EV, typically limit the charge to 85% and discharge to 25%, or 60 percent energy usability, to prolong battery life(See Why Mobile Phone Batteries do not last as long as an EV Battery)

Increasing the cycle depth also raises the internal resistance of the Li-ion cell. Figure 7 illustrates a sharp rise at a cycle depth of 61 percent measured with the DC resistance method(See also BU-802a: How does Rising Internal Resistance affect Performance?) The resistance increase is permanent.

Note: DC method delivers different internal resistance readings than with the AC method (green frame). For best results, use the DC method to calculate loading.

Figure 8 extrapolates the data from Figure 6 to expand the predicted cycle life of Li-ion by using an extrapolation program that assumes linear decay of battery capacity with progressive cycling. If this were true, then a Li-ion battery cycled within 75%–25% SoC (blue) would fade to 74% capacity after 14,000 cycles. If this battery were charged to 85% with same depth-of-discharge (green), the capacity would drop to 64% at 14,000 cycles, and with a 100% charge with same DoD (black), the capacity would drop to 48%. For unknown reasons, real-life expectancy tends to be lower than in simulated modeling(See BU-208: Cycling Performance)

Li-ion batteries are charged to three different SoC levels and the cycle life modelled. Limiting the charge range prolongs battery life but decreases energy delivered. This reflects in increased weight and higher initial cost.

Battery manufacturers often specify the cycle life of a battery with an 80 DoD. This is practical because batteries should retain some reserve before charge under normal use(See BU-501: Basics about Discharging, “What Constitutes a Discharge Cycle”) The cycle count on DST (dynamic stress test) differs with battery type, charge time, loading protocol and operating temperature. Lab tests often get numbers that are not attainable in the field.

What Can the User Do?

Environmental conditions, not cycling alone, govern the longevity of lithium-ion batteries. The worst situation is keeping a fully charged battery at elevated temperatures. Battery packs do not die suddenly, but the runtime gradually shortens as the capacity fades.

Lower charge voltages prolong battery life and electric vehicles and satellites take advantage of this. Similar provisions could also be made for consumer devices, but these are seldom offered; planned obsolescence takes care of this.

A laptop battery could be prolonged by lowering the charge voltage when connected to the AC grid. To make this feature user-friendly, a device should feature a “Long Life” mode that keeps the battery at 4.05V/cell and offers a SoC of about 80 percent. One hour before traveling, the user requests the “Full Capacity” mode to bring the charge to 4.20V/cell.

The question is asked, “Should I disconnect my laptop from the power grid when not in use?” Under normal circumstances this should not be necessary because charging stops when the Li-ion battery is full. A topping charge is only applied when the battery voltage drops to a certain level. Most users do not remove the AC power, and this practice is safe.

Modern laptops run cooler than older models and reported fires are fewer. Always keep the airflow unobstructed when running electric devices with air-cooling on a bed or pillow. A cool laptop extends battery life and safeguards the internal components. Energy Cells, which most consumer products have, should be charged at 1C or less. Avoid so-called ultra-fast chargers that claim to fully charge Li-ion in less than one hour.


[1] Courtesy of Cadex [2] Source: Choi et al. (2002) [3] B. Xu, A. Oudalov, A. Ulbig, G. Andersson and D. Kirschen, Modeling of Lithium-Ion Battery Degradation for Cell Life Assessment, June 2016. [Online]. Available: https://www.researchgate.net/publication/303890624_Modeling_of_Lithium-Ion_Battery_Degradation_for_Cell_Life_Assessment. [4] Source: Technische Universität München (TUM) [5] With permission to use. Interpolation/extrapolation by OriginLab.

The material on Battery University is based on the indispensable new 4th edition of Batteries in a Portable World. A Handbook on Rechargeable Batteries for Non-Engineers which is available for order through Amazon.com.

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Hello, first thabks a lot for the very valable information you gather here and make very easy to understand. However, I m building a battery pack for ebike and wondering if it makes sense having a standard BMS that will balance at full charge 4,2V probably and a charger set to 90% so 4,0V ? So I wont have a balanced pack over the time. My main concern is to have a long life cycle battery. I ll use Sanyo NCR18650GA fin a 10.5ah 36V pack. I know of Smart BMS that can set balancing voltage, but they are expensive and I heard their bluetooth consume extra battery. Thanks ahead for your help

After charging my lithium battery. would it be beneficial to store the battery in the refrigerator at 4 c ?

After charging my lithium battery. would it be beneficial to store the battery in the refrigerator at 4 c ?

I have two queries: 1.) In Table 2, where you have shown Discharge cycles against a DoD. Does this ‘discharge cycle’ in each row denote the same complete 1 Cycle(100% amount discharged and charged, not necessarily in one go) as we understand in battery terminology. Does this one ‘discharge cycle’ imply the same amount for all the rows in the table. Or does it derive its meaning from the respective DoD. For e.g. does each discharge cycle at 80% DoD mean the same ‘100% Discharge/Charge Cycle’ as what is there for 60% DoD? If not, then one discharge cycle at 80% DoD would quantify for 80 units of charging/discharging and one discharge cycle at 60% DoD would mean 60 units. This would mean that 400 Discharge Cycles at 80% DoD, would have delivered 40080 = 32000 Units. 600 Discharge cycles at 60% DoD would deliver 60060 = 36000 Units. And both, as the table suggested, would be left with 70% Capacity.Still pretty good, even if discharge cycle mean different amount of cycle for two different DoD %. But if ‘discharge cycle’ mean the same amount, then it would be even more compelling. 400100 = 40000 units vs 600100= 60000 units delivered with 70% Capacity remaining.

2.) Similarly,Figure 6 should be interpreted wrt context.

Consider two extremes cycles: 75–65%. Black Line 100–25%. Orange Line

After, 400 DST cycles of 100-25% cycle it would have delivered 30000 Units(75400) and would be left with ~92%(from the figure) capacity. For 75–65% cycle, it would have to complete 3000 DST cycles to deliver same amount of units (103000) and it would be left with ~95% capacity. So, 75-65% is actually 3% better than 100-25% when both have gone through same amount of discharging/charging units. No two cycles should be compared for retention capacity on the same vertical line of DST cycles since by that time they have gone through amounts of charge/discharge units. Still, I think as mentioned in my previous point, even for the same amount of units delivered, narrow charge-discharge bandwidth would leave you with more capacity.

Figure 6 is informative, but there is not enough information (at least on this page) to conclude how exactly low voltage affects battery cycles as opposed to high voltage. Does charging from 0-75% have the same effect as 25%-100%? What about 0-85% compared to 15-100%? It is stated in several places that fully discharging is bad for a battery, but is it really? Or is it a myth, given how damaging charging to 100% SoC is?

Alex, Accubattery analyzed figure 6 and found that 75-65% wears 17.5% in 1000 cycles, 75-45% 8.8% and 75-25% 6.5% so that means the depth of discharge does not wear. it’s ok to use up to 0%. link:https://accubattery.zendesk.com/hc/en-us/articles/360016286793-Re-Modeling-of-Lithium-Ion-Battery-Degradation-for-Cell-Life-Assessment

The thing is, the smaller the SoC, the high the cycles. I have an always on tablet. I did some testing and my results conclude the SoC has very little effect on capacity retention given this relationship:

SOC 25-85 25-75 45-75 65-75 Hours for SoC Cycle (including charging) 24 20 8 4 Cycles (1Y) 365 438 1095 2190 Cycles (5Y) 1825 2190 5475 10950 Cycles (10Y) 3650 4380 10950 21900 % Retention 5 Years ~91 ~91 ~89 ~87 % Retention 10 Years ~87 ~88 ~86 ~84

According to SOK battery tech support, this information does not apply to their LiFePo4 batteries or that chemistry in general. Biggest issue would be lack of top balancing unless you have external balancer. I’ll still check around to see what can make these last longer. Their recommendation was to lower the usable capacity on the bottom end to extend lifetime (increased charge cycles but lower usable capacity).

I found that the best percentage for mobile and laptop is 0-50%. I’ve been doing this for over a year on my cell phone and the battery is at 95% health, and my cell phone is almost 4 years old.

At first glance, the 75-65 cycle seems to be the best for the battery, but you need to normalize it for work done: a 50% depth of discharge cycle does 5 times more work, 1000 cycles of 10% is 100 full cycles. This is labeled as work done in the table below.

SoD / EoD: start and end of discharge.

DoD: depth of discharge, SoD. EoD.

Cap % at 4k: capacity lost at 4000 DST cycles.

Cap loss per 1k work done: capacity loss per 1000 full cycles. 1000 cycles is about the full life time of a phone, about 3 years of 1 full charge a day.

SoD EoD DoD Cap loss Work done Cap % at 4k Cap loss per 1k work 100 25 75 81.5 18.5 3000 6.2 100 40 60 83.5 16.5 2400 6.9 85 25 60 85 15 2400 6.3 100 50 50 85.5 14.5 2000 7.3 75 25 50 87 13 2000 6.5 75 45 30 89.5 10.5 1200 8.8 75 65 10 93 7 400 17.5

As you can see, in this model, the loss is with the 100-25 cycle, or alternatively, the 75-25 cycle. It is unfortunate this information is so hidden in this paper.

Also, note that this test was done with a 3.3V nominal voltage cell, which is not a standard Li-ion cell, that chemistry is 3.7/3.8V, so findings do not always transfer.

Adrian, Table 3 and Figure 6 allow you to make a rough calculation and I would say that cycling between 75-45% (approx. ~10% degradation per annum) is better than storing your battery at 100% (~20% degradation per annum). At room temperature (20C) you should expect 80-85% capacity after one year stored at 100% (Table 3). Meanwhile, cycling between 75-45%, let’s say you would utilise four cycles per day (30% x 4 = 120% total battery capacity), five days per week, 48 weeks per year. This works out to 960 cycles which would leave you with ~96% capacity remaining (Figure 6). Furthermore, assuming you store the laptop overnight at ~40%, it will lose an additional ~5% capacity (Table 3).

I can find a lot of information sure. But I can’t find anything for BMS amp for each battery. Do you batterys use a BMS?

Like many people I normally use a laptop in places with a power outlet. To keep to a 75% to 45% use cycle as recommended, I can run a battery monitor that tells me when to disconnect and reconnect the charger. Is there, in existence or technically possible, a way to set the laptop to stop charging the battery at a lower voltage, so that I can leave the charger connected?

Also, if the charger effectively disconnects the battery at 100% and the laptop runs direct from the charger, surely when leaving the charger connected all the time will not affect the battery, which will stay cool, though at 100%. NO discharge cycles, but maintained at 100%. Is this worse than cycling between 75% and 45%?

Can someone please confirm for me I have a 52 V E bike battery lithium ion 19.2 AH, Correct me if I’m wrong I think this is telling me to only charge it to 75-80% full and then run it down to about 25% of discharge for maximum battery life is this correct? and I should always let the battery cool off in my home before I plug it into charge correct?

I am trying to understand this report to clarify. I have a 60V 12AH lithium battery Should l charge it to full charge all the time.

is the 75%-25% cycle number indicative of full cycles? or just 50% use cycles? as if the latter it can’t be compared to 100-25% as that is a 75% use cycle.

Correct me if I am wrong, The closer you keep the battery to 50% charge the better. Also the lower the temperature the better (but not below freezing ofc).

Context: I’m working on a project that uses an 18650 cell as battery backup to power a small processor, where line power is available almost all the time; running off the batteries would be the exception.

Request: Since battery backup systems don’t follow the typical charge/discharge pattern, it would be great to see an article specifically focused best practices for battery backup applications.

Thank you for this article.

A topping charge is only applied when the battery voltage drops to a certain level. !! what is certain level ? can i change it ?

accubattery analyzed the graph from this page https://accubattery.zendesk.com/hc/en-us/articles/360016286793-Re-Modeling-of-Lithium-Ion-Battery-Degradation-for-Cell-Life-Assessment

A device with Lithium batteries (especially Li-ion Li-Polymer/LiPo) should not be left connected to chargers for 1 month unattended. Some cheaper chargers are less safe eg. ebikes, escooter, boards toys. Some devices/chargers stipulate a maximum time for having the charger connected (ofcourse the charger is powered while connected). Notebooks have better battery chargers but you should check atleast monthly for any warping or overheating once you notice the capacity is LiFePO4 are safer for upto 70°C instead of 60°C, piercing doesn’t cause fire. The cells with nominal 3.6V charged to 4.1V (as I 1st mentioned above) are all dangerous when pierced more sensitive to heat.

In figure 6 on this page if you look closely you will see that the discharge depth does not wear out, case 1: 75-65% uses 10% and only provides 90,000 units of power and case 2: 75-25% uses 50% and gives 150,000 power units showing that 75-25% is better than 75-65%, in the old Комментарии и мнения владельцев Reza says just that.

These are other sources that show that discharging the battery to 0% is good

I looked at the source you quoted. According to the information I read under Modeling of Lithium-Ion Battery Degradation, there is nothing there to support that discharging a lithium battery down to 0% has benefit. In fact, if you look at the information the conclusion you would draw is that discharging the battery down that low would have a negative effect on the life of the battery.

The figures clearly indicate that a battery charged to 75% then discharged to 45% has less capacity degradation over time than a battery charged to 75% and discharged to 25%. Why would you think discharging it all the way down to 0% would be a good idea?? For a device that is not constantly needed because a lot of the time it is in standby and the user is worried more about longevity than use 75% to 25% seems the best equation to use. But it certainly isn’t the Best Use for everyone because you end up getting less work out of the battery.

Charging to higher amounts than 75% isn’t necessarily a terrible idea if the device is going to be used immediately in such a way that the voltage wouldn’t stay there long enough to do damage (leaving it charged). For instance, I might charge up my drill to 90% because I’m getting ready to heavily use it. It would be at 90% for so little time it wouldn’t make a huge difference, outside the fact that it might allow me to stop using it at 25% instead of a lower percentage.

Please point me to any sources which indicate it’s a good idea to completely discharge a lithium battery. The only battery chemistry I have ever heard of that this was a good idea for was NICAD. And that was a periodic complete drain, not habitual.

About the ebike battery. You bought this item to use, so use it. Batteries like that can be rebuilt and considering that it costs 1000, likely much cheaper than a new would cost and worthwhile to investigate. I do this for my drill batteries and you may want to do the same- if you’re storing the bike keep the state of charge at like 75% or less. Charge it up to 90% when you are going to use it. The level of discharge is more of a function of use than a real choice you make. I try to charge my drill batteries before they run out, hopefully by around 25% but it’s use and we can’t really control that.

After 3 years of researching how to extend lithium battery, I found that the depth of discharge is a myth, it has zero effect on life, you can discharge up to 2.75 volts without wear and tear, a smartphone turns off when it is at 3.5 volts. what wears out is charging at high voltages. every 0.10 volts doubles the cycles, if charging up to 4.20 volts it lasts 500 cycles, 4.10v 1000 cycles and so on, on this site it doesn’t show how many cycles it’s 3.8 volts, but a guy tested it and it’s 8000 cycles. 3.9 volts is 4000, and 3.7v is 16000 cycles! You can test it now, start discharging the battery to 0%, you will notice a significant improvement in your performance. I’ve been using it down to 0% for 6 months now and the battery health hasn’t dropped at all and my phone is 2 and a half years old. source:https://accubattery.zendesk.com/hc/en-us/articles/212988989-Re-Battery-University-article-BU-808 https://www.powerstream.com/lithium-ion-charge-voltage.htm

I have a laptop with Lion battery, I like to work with it while charging and I discovered that charging it through its USB-c port is very slow. My question is; may I charge it lets say for periods of 8hours while I work?(including that room temperature is relatively low and the battery level does not reach 100% nor 0%) should I let it discharge sometime?

This sentence from What can the user do seems incongruous The question is asked, “Should I disconnect my laptop from the power grid when not in use?” Under normal circumstances this should not be necessary because charging stops when the Li-ion battery is full. A topping charge is only applied when the battery voltage drops to a certain level. Most users do not remove the AC power, and this practice is safe. Perhaps its presumed that all previous advice has been digested and the sentence is only about safety. My reading thus far indicates that the ideal likely for battery life is to not charge it beyond 50% and re-charge it at around 25%.

After 3 years how to extend the initial research battery7, finding that the depth of life, you can discharge up to 2, and for you to have an idea, a smartphone turned off. when it is at 3.5 volts. that wears out is carrying at high loads o. every 0.10 volts doubles the cycles, if charging to 4.20 volts it lasts 500 cycles, 4.10v 1000 cycles and so on, on this site it doesn’t show how many cycles are 3.8 volts, but a guy tested it and 8000 cycles, double 3.9 volts is 4000 and 3.7v 16000 cycles! You can test it now, start discharging the battery to 0%, you will notice a significant improvement in your performance. I’ve been using it down to 0% for 6 months now and the battery health hasn’t dropped and my phone is 2 and a half years old, imagine if I did this from day one.

After 3 years how to extend the initial research battery7, finding that the depth of life, you can discharge up to 2, and for you to have an idea, a smartphone turned off. when it is at 3.5 volts. that wears out is carrying at high loads o. every 0.10 volts doubles the cycles, if charging to 4.20 volts it lasts 500 cycles, 4.10v 1000 cycles and so on, on this site it doesn’t show how many cycles are 3.8 volts, but a guy tested it and 8000 cycles, double 3.9 volts is 4000 and 3.7v 16000 cycles! You can test it now, start discharging the battery to 0%, you will notice a significant improvement in your performance. I’ve been using it down to 0% for 6 months now and the battery health hasn’t dropped and my phone is 2 and a half years old, imagine if I did this from day one.

Can anyone tell me if the information contained on this page applies to LiFePO4 batteries? I heard they were a little different than older Li-ion batteries and also contained battery management systems (BMS)

Buonasera, ho un problema con una batteria acquistata il 21/10/2021 numero 68557475 fattura n° 1508068, messa in ricarica lampeggia spia gialla e non parte motore. alimentatore dell’apparecchio è buono. Visto il poco tempo passato dall’acquisto richiederei sostituzione. attendo un vostro riscontro. distinti saluti.

Good evening, I have a problem with a battery purchased on 21/10/2021 number 68557475 invoice n ° 1508068, when recharging the yellow light flashes and the engine does not start. appliance power supply is good. Given the short time passed since the purchase, I would request replacement. I await your feedback. With best regards.

Thanks for sharing this descriptive post on lithium based batteries.

Does this information give anyone else anxiety. I just bought an ebike that has a huge battery that I would like to preserve (It costs over 1000 dollars to replace). I like to go on long rides (big depth of discharge), But that is of course not good for the battery. I also like the increase of power when it is at a high charge however that is also not good for the battery. Both of these things are bad for the battery and shorten the amount of cycles it can endure. So the question of how high should I charge it, and how low should it go arises. From my research there is no good answer to this question as there are always trade offs.

I have a new cordless lithium battery operated vacuum cleaner at my winter residence. Should I leave it plugged in or not for the 6 months I am away? Thank you.

On the negative side, a lower peak charge voltage reduces the capacity the battery stores. As a simple guideline, every 70mV reduction in charge voltage lowers the overall capacity by 10 percent. Applying the peak charge voltage on a subsequent charge will restore the full capacity.

So this means that I can charge my battery on 3.92v to improve it’s life but if I want the full capacity of my battery at any given moment I can go back and charge with a 4.2v charger? Thanks

My phone battery very fast down

bu-808, prolong, lithium-based, batteries, 18650

In reference to the long life mode above (stop charging at 80% while on AC power): some software solutions introduce a sailing mode that stops charging at 80%, then lets the battery discharge a bit to say 60%, then resume charging back to 80% and so on. This is supposedly to prevent frequent micro-level discharging. charging. discharging. charging etc. between say 79.9% and 80%. This is surely happening with devices that have a power circuit where. even when on AC. the device runs on battery power (cannot draw power from the charger directly to operate. the battery is always in the middle) such as modern MacBooks. So my question is: is this sailing mode beneficial to the battery? Or is the frequent micro-charging around 80% not an issue for battery-in-the-middle devices? Thanks, Peter

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Try Chargie (chargie.org). It cuts off charging at your chosen level and protects any Android phone from premature battery death.

Does anybody know the case for the Nintendo Switch? It must be charged to 100% no matter what when it’s in the dock. So for a device that needs to be charged up to 100%, what would be the best percent to discharge it to?

I have two 3.7v batteries that measure 4v but they need a charge since my drone ran them down. I stored the drone and batteries for several weeks. Now I try to charge the batteries but the charger shuts off after a few minutes and will not light up again even after disconnecting the battery. I discovered that shorting the two battery leads (by accident) ‘resets’ the battery and the charger lights up again only to shut off in a few minutes. I bought another USB wire charger but it does the same thing. I tried to discharge one battery but it still reads 4v. The charger is putting out 5v. What is going on? Thanks.

I have been charging my phone to 65% max and discharging to 25% max ever since reading this article. Am I doing this right?

@ Chad Hi Chad, thanks for the reply. I had thought of that, but the battery that doesn’t show the AC charge option is a brand new and (as far as I can tell) genuine Dell one, while the one that does show it was the one that came with the machine (bought from eBay and therefore origin cannot be confirmed). It’s not life-threateningly important at the end of the day, but it is curious. Ria

@Ria, If I had to guess, I’d say that (a) one of your two batteries is not genuine OEM equipment, but perhaps a convincing knock-off; or (b) a microchip in one of them has malfunctioned, eliminating some Smart behavior.

I have two identical batteries for my Dell Latitude E6430 laptop, type T54FJ. On one of them, when checking the BIOS information, there is an option under Power Management, Primary Battery Charge Configuration, which says Primarily AC Use and then explains that this option Extends battery lifespan for users who primarily operate their system while plugged into an external power source. The other battery, which to all external appearances is identical, does not show this option. My question is (a) what does this option actually do (I can find no mention of it on Dell’s website anywhere) and (b) why does one of two apparently identical batteries show this option as available, while the other does not.

I have a question concerning table 2. Are the two values in the discharge cycles column reflecting a range for the value or are the values specific to the two battery types NMC and LiPO4? Also is LiPo4 equivalent to LiFePo4, mentioned in the following article LiFePo4: https://batteryuniversity.com/learn/article/types_of_lithium_ion? (I was looking there to find Information about the LiPo4 and NMC lifetime, but the tables there show the same cycle life for LiFePo4 and NMC) Thanks!

Google for Chargie stick (chargie.org). It will limit charging to 80 or 90% (or whatever you wish) and your phone will last for many years to come, until its technology is really obsolete. You won’t change phones because of the battery any longer.

Why is using or charging a Li battery below 40% bad? I get that charging above 75% increases voltage to a level which is decreasing battery life. But what happens when you use or charge below 40%? Why is it bad? Thanks in advance!

I wanted to thank you for this advice for lithium based batteries. It’s good to know that the optimal charge voltage is about 3.92V/cell, because it’s believed this eliminates all voltage related stresses. I’m interested to learn if this is the case for all batteries or only lithium ones. http://www.batteryminders.com/aircraft-battery-chargers

what makes the laptop to show that the battery is fully charged when it reaches at 60% and stops charging at the same time?

How can i determine a batteries capacity (how many % it is charged to)? Is it by reading the voltage or is it more complex than that?

Nandagopalan Venkataramanan: You’ve understood it correctly. My Lenovo T60 from 2006 still has about 2,5 hours battery time (original battery and never changed!). I set a profile to start charging when it drops below 70% and charges only to 90%.

https://andrecheung.wordpress.com/2018/02/16/Android-automatically-starts-and-stops-charging-using-automateit-and-ifttt/ describes one way to use a Smart plug to keep an Android phone charged just right

This question is with regards to a gaming laptop: From my understanding, the battery life of the laptop can be prolonged by operating in the sweet spot of 65-75% SOC as per figure 6. But because of reduced capacity at this range, a more realistic and practical operating range would be between 25-75%. Which means I should plug in the power cord when the battery power drops to below 20-30% and allow it to charge upto 70-80% and then unplug and repeat the cycle. Is this the best practice to prolong the battery life of a gaming laptop? Thanks

For smartphones in 2019 there are two constraints. The battery can not be removed. The phone must be on all the time. Given a choice between leaving a phone plugged in for an extended period, which keeps it charged at 100% and reduces the lifespan that way, and letting it discharge somewhat before recharging somewhat over the same period, which increases its cycle count, it is unclear which is worse.

I think there ais a big misunderstanding when we try to select the best choice for charging cycle of our litium batteries. Based on figure 6 we can see in a glance that if someone can use charging cycle between 75% to 65% he will reaches to longest lifetime but this is incorrect! Why? Because he has to charge 5 times in comparison to other charging cycle between 75% to 25% to get the same amount of energy from battery. It means that we must compare capacity loss of first charging cycle after 7500 cycle with capacity loss of second charging cycle fter 7500/5=1500 cycles. As you can see in both charging cycle the caacity loss is the same and about 92%! So I think it is necessary that we have another figure that shows the capacity loss vs delivered energy and shows how different charging methodes behavior is different. I think maybe the best and realistic choice for best battery care is using the 75% to 25% charging cycle. I appreciate this site especially if they add mentioned figure to their very useful figures. Thanks a lot.

Thanks for explaining how the capacity of a battery drops compared to the number of cycles it has run through. I had no idea how significant this was until I saw it on the graph. Maintaining and replacing batteries is more important than I thought.

heres what I am doing to prolong my Android cell phone battery 1. Download GSAM on Android. Figure out what charge percent is 3.92v/cell (on Samsung it is around 65%) 2. Buy a WeMo Smart switch. 3. Download tasker. I made a IFTTT task to turn on my wemo switch when it hits 60%. Turn off at 65%.

I just purchased a Makita 18 volt sub-compact Drill/Driver and impact drill kit. It came with 2 2.0 mah batteries. I don’t intent to use the devices daily nor even monthly. I may wind up maybe using them only 4 times a year at most as a week end warrior. So the batteries will be sort of in (semi-)long term storage. I want to store the Li-Ion batteries at the recommended 40 percent state-of-charge (SoC). I can’t find any reference as to what voltage the 40 percent SoC should be for an 18 volt battery. I can only assume at this point that they should be charged at more at than 18 volts. I just fully charged them and I measured the voltage at 20.62 volts. I know the recommended SoC for a single 3.7 volt Li-Ion battery cell is between 3.82~3.92 volt. I don’t know how many cells are in the 18 volt battery pack. If I were to assume that they are 5. 3.7 volt batteries connected in series, should the 40% SoC be between 19.1~19.6 volts? Would someone please contact me and let me know the correct 40% SoC is for my 18 volt Li-Ion battery pack. Until I confirm what the 40% SoC should be for my 18 volt Li-Ion battery pack, I plan to fully charge them every 3 months. Thanks in advance.

Came across an interesting research paper published 2 years ago by researchers from the Technical University of Munich. You can download the paper here: http://mediatum.ub.tum.de/node?ID=1355829 It is a very long read as it covers everything age-related to lithium-ion batteries like aging processes, calendar and cycling aging, impact of charging methods and more from an EV application perspective. They go into detail how they analyze the batteries and their degradation, it goes beyond my level of understanding but it is very insightful. On page 88/89 of the paper you have table 4 above this site projected to a graph. Their findings is similar with what is shown on this website, although the cycles are lower since they were discharging down to 2.5V. Their results show that you must compromise between better battery longevity or a larger usable capacity in a battery. Unfortunately the relative capacity of decreasing charge voltages does not intersect each other. In practical terms, yes, you can charge from 20-80% and have a similar capacity after 1000 cycles, but the usable capacity will always be less than if you did 20-100%. According to the study, after 750 cycles of charging to 100%, the battery will always give you more run time than 750 cycles to 80%. This means the only benefit of reducing charging voltage is to avoid the battery capacity from dropping over time, at the cost of usable capacity. Also, the benefits of reduced charge voltage is negligible past 3.8V, or around 40-50%. Depth of discharge also has a significant effect on cycle life. Reducing the depth of discharge will give the battery a higher capacity over time more so than just reducing charge voltage. Combined with reducing the charge voltage as well, capacity degradation is substantially minimized. Batteries prefer resting at a low state of charge, where stresses are its lowest. This lines up with Figure 6 above that shows 25-75% has a higher capacity over time than 50-100%. I also wanted to point out the results of cycle life on fast charging. Unfortunately in all cases, any form of quick charging, whether by Tesla’s Supercharger or increased current at initial charge, will always result in significantly reduced cycle life due to excessive lithium plating and stresses on the battery. To sum it up for optimal battery life, disable quick charge, charge as often as possible and keep the percentage as close as you can to 40-50%. If you need a longer run time, charge to a higher percentage then drain to 10% for maximum capacity at the cost of reduced life. This minimizes the charge voltage for the extra depth of discharge you require. I know this is a long comment but I hope people find this helpful.

@ Silcestre Martins Yes. I think so. Do not fully charge and discharge the lithium cells will prolong they lifecycle

I have one question: if we limit the voltage to 4.10, then we can expect 85-90% of full capacity available (Table 4). My question is: this is exactly the same as disconnecting the device from the charger when it has reached the 85-90% capacity, right?

Something that I can’t help but wonder. But don’t see mention of. What I’d call microcycling. In the land of endless switching power supplies, we already know that the harsh transients they produce (at both ends, supply and load sides), cause electrolytic caps to age at an accelerated rate. And not every battery installation fits all nice and tidy into the experiments listed in the article (which BTW is indeed very informative and comprehensive for what it covers). One example of this would be in a live UPS system where the battery may be exposed to both charge and discharge spikes rapidly and repeatedly (function of charger, inverter, and/or both). What constitutes a charge cycle has long been a topic of debate. But semantics aside, it would be illogical to think that batteries in certain equipment would not be affected by the same forces that rapidly and radically reduce capacitors to leaking tin cans. Especially with all the corner cutting cheaper grade equipment that we are swamped by in modern times.

I last visited this page back in 2011/2012, and see substantial changes in figure 1 and 2. (Not photographic memory, copied numbers LOL eskerahn.dk?p=250 ) Is this due to newer batteries behaving very differently? Back then the batteries went from 100 to 70% over their lifespan, and more interesting, the estimated accumulated number of power cycles you would get (The product of the two first columns of fig 2, integrated from 100% to 70%) showed a substantially better usage at about 50% DoD vs 100% and 10% With the current the usability is best at 20% resp 10% for NMC resp LiPO4 So is it today better to do small DoD? A handful of years ago it was clearly bad.

Michael. I think the validity of your observation will also be graphically supported if the graphs were based on the ‘weighted’ cycle lifespan that I proposed. I am hoping that by and by, the weighted cycle lifespan will displace the presently used numerical cycle lifespan.

Cassim makes a great point about kilowatt hours but let us talk practically speaking. If you charged to 100% and down to 25% average roughly 600 cycles per year (that’s more than 1.5 per day). you’d only reduce your battery capacity 5% in THREE YEARS and that is absolutely a worthwhile tradeoff to having 3 years with 15-20% less battery capacity with you! If you can get one battery replacement after 1-2 years, your phone should last 5 years charging to 100% and a much superior experience while you’re using the phone.

For a battery of full capacity 40kWhr, if total number of (lifetime) Charge cycles obtainable with a 75% – 50% charging regime is 4,000 and total number of (lifetime) Charge cycles obtainable with a 75% – 25% charging regime is 1,800 The 75%. 50% regime gives a total energy for use during its lifetime [0.25 x 40 x 4,000 = 40,000 kWhr] compared to the 75%. 25% regime which gives an energy for use during its lifetime of [0.5 x 40 x 1,800 = 36,000 kWhr]. Thus, the comparison should be between 40,000 kWhr 36,000 kWhr and not between 4,000 cycles 1,800 cycles. The actual comparison can be made to reflect this if ‘weighted’ lifetime cycles are used where: actual life cycle number is multiplied by the fraction of full (100%) charge of the charge regime used. In the preceding case, ‘weighted’ lifetime cycle for the 75%. 50% regime would be 0.25 x 4,000 = 1,000 cycles for the regime of 75%. 25% the ‘weighted’ lifetime cycle would be 0.5 x 1,800 = 900 cycles. Thus 1,000 compares with 900 and reflects the actual performance difference of 10% that is applicable. Comparing 4,000 cycles with 1,800 cycles in not very meaningful as the energies stored per cycle vastly differ.

in respond to Vortex : i think you wrong in calculating ‘cycle and use’. a cycle is from 0 to 100%, 10 to 110%, 20 to 120%. (100% capacity, not only from 0.) (i.e charge the battery 1010% is 1 cycle. (timescapacity percentage) so all the charging method here giving the same amount of charge to use, but with diffrence in life expentancy. in respones to Hoon : i have Galaxy s7 edge in use also. i have 63% capacity from a ‘full charge’ lol (~2250 mAh from 3600 mAh) i didnt followed any advice (=didnt know.). charged to top, and drained to 0% lol and in hot climate. i have it for 2 yrs and 2 month now.

Great, thanks for sharing information about how mobile battery can be kept healthy. You have really listed nice points to take care of the mobile battery life. From my side, I would recommend not to use animated wallpapers which might eat not just the battery but also the processor speed. I would also suggest not to drain the battery to 0%. Everyone should apply charger when battery get down to 5 or 10%. Anyways, very nice article. Couple of points which I was not aware of are mentioned in your post. Keep sharing and good luck.

As most of the posts here are in reference to smaller batteries and smaller voltages, I’m not sure as anyone can help out, but here goes. I bought a 58v battery powered lawn mower on 12th May this year and have charged the battery 6 times up until now ( 12th November ) but now it will not charge at all. There is zero charge showing in the recharge window. I have contacted the supplier of the mower and I’m told there is no warranty on consumables i.e. the battery. Surely this 158.00 battery is only fit for the tip? Can anyone suggest anything I can do to bring it back to life? Thanks.

Hey guys, just wondering in terms of preserving battery lifespan, is it better to keep a lithium-ion device at 100% (using it while plugged in) or cycling it at 50%? The reason I ask is because there is a device called a Nintendo Switch, which is a video game console that can be plugged to a TV via a dock or taken on the go. The dock also doubles as a charger. I understand keeping it between 80%-40% is probably ideal but for this kind of device it isn’t really doable without large disruptions to the experience. I like to hook it up the TV which means it’s usually at 100% for long periods of time but I can start switching it between docked and handheld mode (to discharge to 50%, which is as much micromanagement as I’m willing to do) if that’s ultimately much healthier for the battery lifespan. Thanks a lot!

The articles here are great but getting answers on these discussions is even better. I just wanted to say thanks to all who contribute!

If I buy a lithium ion new battery(no named brand) that has a date stamped on it from 2016 should I use it in my Samsung cell phone? I bought it on Amazon.

As far as I can tell, the study cited for Figure 6 indicates that they use a constant charge rate of 1C for recharging in the study, but most Li-Ion chargers use a tapered rate and avoid 1C near 100% SoC. Doesn’t this mean that the curves ending in a 100% SoC are unrealistically inflating the degradation of the batteries? Also, this page and graph are cited a lot in the Electric Vehicle forums, but again the graph is based on ambient temperature cycling (the study indicates that the legend only lists the room temperature, not the cell temperature). Many of the newer EVs are coming with active battery temperature management to fight the negative effects from the heat generated from charging (something the Leaf models that had issues in warmer climates lacked in the first iterations), so again, does the graph need a footnote indicating that it may not apply to EVs with active cooling?

Hi I want to use an ultimate lithium battery in a camera trap for 30-days continuously. How long would it last?

Gracias por tan exhaustiva información, me ha servido para ampliar mis escasos conocimientos sobre baterías de Litio

if you’re really want to maintain your cell phone battery’s life, you should be charged your cell phone around 80 percent in one go.

To charge the battery exactly 80% and download it up to 40% as advised in the article I recommend this Battery Limiter program, it is really useful, it allows you to configure those percentages http://www.robotonfire.com/bl/

@Yang That is normal, it is a new battery so it will have brand new set of cycles and 100% health. The cycle count is only an estimate from charging 0-100% and not that accurate. Also depends on the device. @Jesse Yes the information still applies, but voltage capacity is different. For a 3.85v battery, 4.4v is at 100%. Doing the same for a 3.6/3.7v will drastically reduce cycle life. Reducing Depth-of-Discharge and Charge Voltage still benefits the 3.85v battery. Battery University goes into depth here: http://batteryuniversity.com/learn/article/confusion_with_voltages

Does this information apply to a 3.85 (nominal) li-po (OnePlus 6)? What I mean, does going past 4.2 on it while charging have the same effect as going past 4.2 on a 3.6/3.7 li-ion?

Errata in the text relating to figure 7: If this were true, then a Li-ion battery cycled within 85%–25% SoC would fade to 74% capacity after 14,000 cycles. If this battery were charged to 85%. Changing the charge level from 85% to 85%? The first 85% should be 70%, to be consistent with the graphs.

I have a question. i recently changed my battery but searched the battery discharged cycles and it show 500 and a battery health of 93%. but it is a new battery. is that normal ?

Is it ok to buy an aftermarket device to lower charge Voltage on a laptop? I’m trying to extend a battery life, but can’t work on a slow and dim PC. I don’t do games, but run diagnostics and/or math related calculations, sometimes charts/graphs. If I were to slow performance there is a lag in response. Thanks.

20% DoD ~1,500 / 9,000 IS THIS NOT AN ERROR? SHOULD BE 4.500 / 9.000. I am guessing that the ‘1500 cycles’ should have been 3750 cycles and 4500 cycles, giving 750-900 full-cycles of power from a battery that is cycled at 20% Depth of Discharge (DoD).

Table 2: Cycle life as a function of depth of discharge. A partial discharge reduces stress and prolongs battery life, so does a partial charge. Elevated temperature and high currents also affect cycle life. Note: 100% DoD is a full cycle; 10% is very brief. Cycling in mid-state-of-charge would have best longevity. 100% DoD ~300 / 600 80% DoD ~400 / 900 60% DoD ~600 / 1,500 40% DoD ~1,500 / 3,000 20% DoD ~1,500 / 9,000 IS THIS NOT AN ERROR? SHOULD BE 4.500 / 9.000. 10% DoD ~10,000 / 15,000

If I am eyeballing Figure 6, I get the following numbers. I am looking at the total amount of energy (in full cycles) I get before I hit 90% battery capacity: 75%-65% = 0.1 x 9000 = 900 full-cycles 75%-45% = 0.3 x 5000 = 1500 full-cycles 75%-25% = 0.5 x 3000 = 1500 full-cycles 85%-25% = 0.6 x 2000 = 1200 full-cycles So I would conclude that 75%-25% is the best recharging schedule, since it gets you 1500 full-cycles worth of power before the battery degrades to 90%.

Best to let it get to X% charge before recharging.-0% if single 4.2v battery 10% if greater voltage Best to charge it to Y%.-60% best. Is it ok to leave it charging all night?-no Is it okay to remove it from charging at any time?-yes Is it okay to use it while charging?-yes How

Great info. for the tech oriented folks. Thanks. Really. But how about a bullet point explanation for those of us who don’t want to read 5000 words and just want the basic idea of what is best for our Smart phone? For instance how about a bullet point explanation of the following: Best to let it get to X% charge before recharging Best to charge it to Y% Is it ok to leave it charging all night? Is it okay to remove it from charging at any time? Is it okay to use it while charging? How bad is it if it runs down to 0 charge? How much does it reduce the life of the battery if I pay no attention to any of these best practices and just charge it when I want and remove it from charging when I want?

Hi Thanks for a great site. I have been trying to estimate lion battery capacity SOC from voltages. I know its inacurrate at best. BUT on this page; http://batteryuniversity.com/learn/article/charging_lithium_ion_batteries you indicate 3.8v approximates to 60% charge(table 2). But on this current page(table 4) you indicate 3.8v is around 35-40% charge. Can you offer more info on this? Thanks John

Can someone give me some feedback related to BATTERY LIFE in terms of wired vs wireless charging (fast charging disabled)? I already know that fast charging CAN reduce battery life. Do we have any info on wireless charging? Since it’s an inductive charging, some part of it’s energy it’s released as heat (not used for charging) and I think it SHOULD affect the battery. The wireless charger I bought is a Wireless Qi Fast Charge Standing Samsung EP-N5100 with fans incorporated to reduce the heating. (Yeah, I use it on a compatible Samsung smartphone) I made the mistake to have the fast charge active for some time (didn’t know it was active by default), but I only charge it from 40 to 80 so I hope no less damage has been done. Since I plan to keep the phone for a while (I doubt I’ll switch in 2 years), I want to try and be careful with the battery.

You’re absolutely correct, most people will not keep their devices or phones long enough. Those that do, however, can benefit from the information above.

Hi Paul. Thank you for your response. The discrepancy that I am referring to, however, is not in regards to the maximum battery capacity. It is in regards to the number of discharge cycles presented in Table 2 and Figure 6. Table 2 states that a certain level of degradation will occur after ~400 cycles, whereas Figure 6 presents a lesser level of degradation after exceeding ~4,000 cycles. That’s a 10 times difference in the number of cycles! (and the huge discrepancy that I am referring to). I hope someone can provide more insight. For ease of reference, I will quote my previous post: “Figure 6 presents that a 75% DoD will results in 21% loss in maximum battery capacity after ~4,000 discharge cycles, whereas Table 2 presents that an 80% DoD will results in 30% loss in maximum battery capacity after only ~400 discharge cycles (10 times fewer cycles compared to Figure 2!). Which one is correct?”

Thanks for this valuable article. Over the years, this information has proven to be accurate. For the first 2 years, I used to keep my laptop plugged in all the time with 100% charge state. Unsurprisingly, the battery capacity had degraded by about 25% over that time. After reading this article, I started storing it at 40% and charging it to 80% at most ( while seldom charging to 100% just to calibrate). Seven years after the purchase, my laptop can still get at least 2-3 hours of moderate usage, while colleagues with 2014 or newer models need to carry their chargers with them. Another example is with two LG Android phones, which I bought in late 2014. One of them (mine) was charged using the 40-80 method, while the other one was used normally. Over 3.5 years later, my phone has retained about 85% of it’s battery capacity, while the other one is roughly at half or less. The problem is that battery replacements available for sale are as old as the one currently being used, and they have also degraded over time. That perfectly functioning phone will need to be replaced for this very reason. So, take care of your batteries, better do a 40-80 charge once a day (i use an app to limit the charging) instead of 10-100 charge every two days. And charge to 100% when you know you are going to need it!

At the above poster (Peter). a difference of 30% and 20% is not a massive difference when you’re considering lithium ion batteries. That’s in the same general ballpark. Every battery is going to act a little bit different. Just remember that when you say you expect an average of 2 charges per day, you aren’t talking charge cycle, right? A charge cycle is a complete 100% to 0% drain (this is 1 cycle). Charging from 100% to 50% and back to 100%. doing this twice is 1 charge cycle even though I charged the phone twice. So doing 2 charge cycles a day is extremely rare unless you’re a super heavy cellphone user. My wife uses her phone a lot and only averages 360 cycles on her iPhone 6s after 1.7 years. I an a more moderate usage and I only use about 220 after 1.7 years (I had a 6s as well). You are very correct. most people will get a new phone at or around 2-3 years. Most users will not have consumed enough cycles to really make an effect. My wife’s iPhone lost about 3% design capacity after 360 cycles. My phone stayed the same (design capacity). You’re absolutely correct, most people will not keep their devices or phones long enough. Those that do, however, can benefit by the information above. Batteries are incredibly variable. some will hold designed capacity after many cycles, some aren’t so lucky. On average, if you do a 40-80% charge, your battery will keep its design capacity over a much longer period of time than someone who does 0-100% or keeps their phone at 100%. I think your expecting to use 2,190. 3,650 cycles is incredibly high. My wife is a heavy user of her phone and she’d be lucky to hit 400 after 2 years.

Hi, I would like to start by thanking the author(s) for gathering all these helpful data and informing the public. I have, however, noticed a huge discrepancy between the number of discharge cycles presented in Table 2 and Figure 6 that I hope someone can provide more insight. Table 2 presents that an 80% DoD, which I interpret as charging a battery to 100% and discharging it to 20%, will cause the maximum battery capacity to drop to 70% after ~400 discharge cycles. However, in Figure 6, the dynamic stress test indicates that, by charging a battery to 100% and then discharging it to 25% (black line), the battery will retain 79% of its maximum capacity even after 4,000 cycles. In other words, Figure 6 presents that a 75% DoD will results in 21% loss in maximum battery capacity after ~4,000 discharge cycles, whereas Table 2 presents that an 80% DoD will results in 30% loss in maximum battery capacity after only ~400 discharge cycles (10 times fewer cycles compared to Figure 2!). Which one is correct? As someone who is prepared to replace my electronics in 3 to 5 years, I am expecting my battery to undergo between 2,190 (3 years) to 3,650 (5 years) discharge cycles with an average of 2 charges per day. According to Figure 6, if I charge my battery to 100% and discharge it to 25% (75% DoD) every cycle, after 2,190 cycles, my maximum battery capacity will be at 85% and after 3,650 cycles, my maximum battery capacity will be at ~80%. I find this level of degradation acceptable and will not make any changes to how I charge my battery. However, according to Table 2, an 80% DoD (charging to 100% and discharging to 20%) will decrease the maximum battery capacity to 70% after only 400 cycles (roughly 7 months) and will warrant a change in my battery-charging behavior. Again, I am curious to know which of these two is correct. Note that both Table 2 and Figure 6 does not consider battery degradation over time and for the purpose of this discussion, let’s not consider the effect of ageing on the battery. I am aware that Li-battery starts to degrade as soon as it leaves the manufacturing line. However, if the response to my question is simply, “Li-battery degrades naturally, so after 2 years you are expected to get a new one”, then there is no point to this discussion. Why bother making changes to your battery-charging behaviour if natural degradation is more detrimental.

Regarding the Комментарии и мнения владельцев on teslas. they’re holding up fairly well. https://electrek.co/2016/11/01/tesla-battery-degradation/ https://electrek.co/2016/11/01/tesla-battery-degradation/tesla-battery-degradation-3/ https://electrek.co/2016/06/06/tesla-model-s-battery-pack-data-degradation/ https://www.teslarati.com/how-long-will-tesla-battery-last-degradation/ http://evobsession.com/tesla-model-s-battery-degradation-level-5-30000-miles/

Now apply all this on Tesla battery, which is also lithium. so imaging how fast the car is charging and discharging compare to a phone, no one gonna charge the car to only 75% anyway and charging a tesla at around 90kw will cause the battery temperature at around 40C, which is basically at the temperature of a phone working on full time benchmark running. base on these. the tesla battery will probably only have 50% of battery after 3 years. depend how often you charge it.

I have booked marked the page for future reference. that voltage information is invaluable understanding of battery life and how are care plays a role in it. an.Ive been honing the charge / discharge skills these last few days in prep for this weeks test rides with a new ebike build and its combined 25AH of batteries. I want to add for those who use their laptops plugged in predominately you can install a app to set the charge to charge to 60% capacity (or what ever you choose) as it can/will extend the battery life by years. I myself have been using the Lenovo battery saver app on a Lenovo notebook since new. I expect to get 20 years out them as they have 25 cycles on them now after 2 years. My adice to all Li-ion users is to charge to 60 to 80% and top up to 90-95appy charging

I read about this website it will very useful for basic understanding about batteries i will suggest you to read this site very carefully. thanks for all other Комментарии и мнения владельцев

ID be grateful to anyone that could provide a viable solution. I need to balance 12v 110Ah LiFeMgPO4 lithium iron magnesium phosphate batteries. There are 2,544 in total / 48 packs of 53 in series. Each battery has 4 cells approx 3.5v Un-terminating them is an unreasonable option. If there is a good method to charge/ balance in bulk, while in series ID sure like to know. this has been an epic tedious undertaking. so far we’ve been charging the whole pack until one of any cell in any module reaches 3.8v. Then using truck chargers topping off the low modules. After that discharge the entire pack, charge again and repeat until they get tighter. There has to be a better way.

Many devices do not show how charged they are. headphones, speakers, flashlights, and more. One strategy with them is to use an in-line meter that shows the current used. These are readily available for USB on ebay elsewhere. Once you have the meter, you can watch it to see the maximum charge reached when recharging from empty then charge to the level you want. You can time this then use a timer to tell you when to shut it off. This works if you always completely discharge the device or battery. Another strategy, with a device, is to watch the current flow. Devices are Smart enough to cut down the current as it reaches full, by monitoring the voltage or temperature. So if you see the current steady for a while, then start to drop, you can stop charging the moment you see the drop in current. My guess is that this happens when approaching 80% full, a reasonable tradeoff between battery life and battery longevity.

I extrapolated graphically the data from Figure 6 to more cycles using an intrapolation/extrapolation program with default settings assuming there’s a linear decay of the capacity retention with the number of cycles: http://oi65.tinypic.com/iejbip.jpg If so it can be expected a drop of battery capacity retention to 75% after 13000 cycles in the 75%-25% scenario, drop to 70% after 11000 cycles in the 85%-25% scenario and, the worst case, drop to 70% at about 7000 cycles when using 100%-25% scenario.

Hello! In response to Evi1M4chine on November 2, 2017 at 10:26pm Have in mind please I am not an expert- If we consider the whole energy transferred to the device by means of the battery we, I think, could better understand the cycles vs. use time thing. Now. Discharging the battery 10 times by 50% (let’s say from 100 to 50 percents) gives the device the energy equivalent to 5 full 100% discharge, or 5C, 5 batteries, to say 🙂 I’ll try to calculate this energy from the data plotted in Figure 6: Capacity loss when operating Li-ion within given charge and discharge bandwidths. Let’s consider the battery started to degrade and it’s full state of charge is at 90% as compared to the initial state which was 100%. From the data plot we see that if the battery discharge is driven at 100% to 25% range it reaches 90% capacity retention after 1000 cycles. On the other hand if the battery discharge is driven at only 75% to 65% it reaches 90% capacity retention after 9000 cycles (extrapolated). Much more cycles but with less energy transferred to the device in a single cycle. So the whole energy transferred to the device when sycling at 100%-25% is 75% multiplied by 1000 which gives 750 C. C is the full virgin capacity. In the case of 75%-65% we have 10%9000 = 900 C. Calculated this way we obtain the following: 75%-65%. 900C 75%-45%. 1500C 75%-25%. 1500C 85%-25%. 1200C 100%-50%. 800C 100%-40%. 720C 100%-25%. 750C till the battery reaches 10% capacity degrading (90% retention). As one can see there is an optimum in this therms and I would prefer 85%-25% or 75%-25% discharging.

On September 6, 2017 at 2:45am MKING wrote: We have a new MacBook Pro and it gets warm when charging. I am considering the purchase of a lower-wattage (amps) charger which will charge slower and at maybe a lower induced temp. for the battery. I have used a lower powered charger on my mobile phone and it does seem to help re temp. and battery longevity. Am I on the right track or deluded? I still don’t know what to do? Do I charge slower or as rapidly as possible? I am doing 20% to 90% at present but it seems I should be recharging at 40% and unplugging at 80% to prolong the life? I am now using an older HP laptop as a TV streamer and am actually removing the battery when it it ‘on the mains’. this ought to help the battery stress by no being connected or in use. yes?

I have a question, so if the best percentage to store a lithium battery is 40 percent, why is it the the longest cycling is 65- 75 percent? Shouldn’t you try to keep the percentage to 40 as much as possible? So maybe 45. 35 percent? or is there something i am missing out?

Table 3 figure text says that the numbers are for 1 year, but in the lowr right corner of the table it says (3 months). So which is correct? And what does the 3 months refer to if not the period of storage?

One thing missingg in all of this, seems to be, that longevity seems to be measured in charge-discharge cycles, instead of total use time! Because, of course you get more cycles if you only use it for a part of the capacity. Duh. The total amount of discharging/use might still not be better! I hope you can answer this, as it is really preventing me, from being able to draw any useful conclusions from this. :/

Hello Explanatory text. Thank you About new smartphone charging technologies, do they hurt the battery? Or are they functional and secure? Thank you Claudio (Brazil)

Lead-acid batteries emit hydrogen and oxygen at the end of charging. Neither is toxic. The mixture is flammable.

Lead Acid batteries during charging emit toxic gases during charging and especially at electrica fork lift trucks. What about the large batteries charging gassing of EV vehicles?

Suppose I want to charge my cells to 4.08 volts. What is best in order to minimize the stress: 1. Charge to 4.20 volts with high current (1-2 amps) en then stop when voltage is dropping. The end result then will be about 4.08 volts. 2. Set my charger (SkyRC MC3000) to charge to 4.10 volts and let charging go on till the voltage drop to 0.1. 0.2 volts. Also here the result will be about 4.08 volts. The first method is of course the fastest, but will bring the cell shortly at 4.2 volts. The second method takes much longer (also stress), but never make the cell’s voltage above 4.1 volts, being 90%.

We have a new MacBook Pro and it gets warm when charging. I am considering the purchase of a lower-wattage (amps) charger which will charge slower and at maybe a lower induced temp. for the battery. I have used a lower powered charger on my mobile phone and it does seem to help re temp. and battery longevity. Am I on the right track or deluded? Thanks

Is keeping battery at 100% as bad as deep discharge to 0%? What should I do? I have a MacBook Air but I use it as a laptop. connected to power, its battery always at 100% How often should I disconnect it and how deep let the battery discharge? Why don’t manufacturers explain this? This is the most ignored question ever! 🙁

What is the maximum discharge voltage / deep discharge voltage of Li-ion battery. What will happen if i discharge the battery (Li-ion) to 2.3V. Battery part no: ICR18650B3 Manufacture : LG Chem

Trying to figure out what voltage equates to 40% SoC? My batteries are Li-ion (NCA). I thought that the voltage range was approximately 3.0v-4.2v and that would mean that 40% SoC was approximately.4 x 1.2 3.0 = 3.48v. I read on the Battery University site that At 40 percent charge, most Li-ion has an OCV of 3.82V/cell measured at room temperature. What am I not interpreting correctly? My sincere Thanks for all of your help.

I don’t know if you will read this since this is a couple weeks late but I’ll reply anyways since it might be helpful to others. I know that for smartphones they use varying lithium chemistries that change their nominal voltage, and thus their charge terminal voltage. In fact I’d argue the majority of phones nowadays use lipo’s that terminate far above 4.2V, 4.4V is probably the norm. No need to worry, just look at percentage, 100% is still 100%. Totally fine to disconnect at 80%, just look at figure 6 to charge how you want it. 80%, is good, less then that is better. Now for quick charging, in theory quick charge 1.0/2.0 will reduce the amount of cycles the battery has left. Their specs indicate a faster amp draw, which will result in more heat and stress on the battery as you experienced, and thus amount of cycles. However quick charge ONLY activates from 0%-50 or 60%, after which it will switch back to standard charging. With the large battery capacities nowadays, any phone with more than 2000 mah will safely quick charge below 1-1.5C, which won’t significantly affect battery capacity. This means in reality stress is limited, current is tightly controlled to avoid overheating, and the damage is minuscule you may not even notice the change in capacity. With quick charge turned off, you can charge from your mains adapter much faster than your USB port with nearly no difference in longevity up to 0.5C. WIth a Moto G4 (3000mah), that is any adapter up to 1.5A. Ultimately it’s up to you, if you want to maximize longevity and/or you keep for phone for 3years you can just turn quick charge off, and charge with the mains adapter. info on charge rates at BU-401a: Fast and Ultra-fast Chargers. 0-50% is definitely better. There was a military study done on it, it was on Tesla forums but I don’t remember the link. Reason being that 100% keeps the battery stressed more at high voltage than at 0%, and you are normally above 0%. Of course 0% is still bad, the cell begins failing, but the phone will protect from that (0% is not actually 0%). This is why I recommend 20-50% or even better, 40-50%. Of course that only gives you only 50% of battery for emergency, so you can up that to 60 or 70% with a slight reduction in battery life. 60-70% is better than 50-70%. Look at table 2. You reduced the depth of discharge by 10%, but gives nearly 10x more cycles. Why 10x? I don’t know, but it’s just the way the battery is and with mpoweruk.com/life.htm saying the same thing as Table 2, it must be right. The answer is the less energy, electrons, you give to a battery, the more cycles you get. They even claim cells in microcycle applications (charge and discharge pulses) can get 300,000 cycles. Again, in reality you won’t see it, but those are the conclusions. Hope this helps!

My another question is, which is worse, 0% to 50% every day or 50% to 100% every day? The figure 6 doesn’t show any result tested below 25%. So my question ultimately would be: which is worse, overcharging or overdischarging? I don’t know if they’re the correct words. I have a feeling that 100% will be worse than 0%. My yet another question is, which is good, 50% to 70% 1000 times or 60% to 70% 2000 times? I really want to know if an amount of energy (=electrons?) you give to a battery at a time matters or only SoC (=voltage) is important in this case. And apparently, if you use Chrome and have its data saver turned on, you can’t add a comment on this site.

The figure 6 is just mind blowing! I’ll try my best to prolong my smartphone or anything’s battery life that uses lithium ions as much as possible. Thank you so much for this useful article! However, I use a battery monitoring app on my phone and it shows battery voltage. And while charging, above 70% the voltage is 4351mV and it seems constant. But it can be as high as 4470mV. When unplugged, the voltage drops to around 4200mV in several minutes. My question is, is this normal? I mean, is it OK for my battery? The article says no to above 4.2V. But I don’t think this is just my device, which is Moto G4 Plus. My previous phone was Nexus 5, but the voltage while charging was also above 4.3V, I believe. Are current smartphones’ batteries are different from ones that are described in the article? Should I abandon the manufacturer’s charger with Quick Charge and always charge from my PC’s USB port though it’s super slow? Because when I charge it that way, the voltage is kept much lower. (The phone doesn’t get hot also.) Is it OK if I disconnect the charger before it reaches, say 80%, or is it that high voltage harms my phone’s battery no matter what the final SoC is? I hope someone will answer my questions.

can a lithium ion battery used to charge a electric bike. be used to charge a electric stove(like a hot plate) ?

Someone told me a metaphor. think of your Li-ion battery as 2 flavors of pudding. When the vanilla mixes with the chocolate, the charge depletes. If only a little mix it can be separated easier, but allowing them to completely swirl makes it real hard to separate the flavors (the positive and negative charges). I don’t have any proof of this but it makes it easy to think about. I keep my system plugged in most the time but if I wanna take it somewhere I just let it get no lower than 3/4 or so. Not like the old days where you had to train your Ni-cad’s (and I think NiMH wanted full to 0 too iirc) So best I can tell don’t quixk charge Li-I batteries and don’t let em run all the way out. Heck my 3DS has been on for 3 days and still has 2/3 charge, tho a lot was in standby mode.

my question is that i have s6 edge, i want to expend his battery life as long so what can i do, which percent age % i can charge my phone 15 or 40 % to till 100% percent please tell me about this situation. as s6 edge has 9 volts battery?

I agree definitely charging from 90% to 100% will wear the battery faster because it is hitting a higher voltage, and the battery is stressed all the time at 4.2V since it is never given a chance to drop down and relax. Going from 90%-100% will probably kill the battery faster than charging from 25%-100%. My point was, in theory, the shorter you keep the charge times (lower depth of discharge), the more life you can squeeze out of the battery. Based on the table and graph going from 40%-60% is better than 20%-60%. Doing this will increase the amount of cycles because there is less stress. Of course this doesn’t apply to 100% cutoff, because constantly staying at high voltage alone will kill it. Ideally if there is always an outlet nearby, the best time to charge it is 40%-50% so that it minimizes voltage cutoff and DoD to extend cycle life. As I said before this is unrealistic, so we try to charge it as soon as possible and disconnect it at the earliest, whether it is 50% or 70%.

Jeremy wrote:. From what I read here and other studies I can conclude that it is best to make frequent, short charges, 10% or less ideally, and keep maximum charging voltage to a minimum. Though of course realistically that is difficult, it is better to do frequent top ups, and disconnect the charging as soon as possible, within reason. According to the guys that make the AccuBattery app for Android, keeping it between 90% to 100% will cause similar wear on the battery as doing: charging from 70%-90% (using 20%) charging from 40%-80% (using 40%) charging from 10%-60% twice (using 100%) or something like that. All numbers are made up by me just to show the point. Keeping the voltage high (besides heat) wears the battery, so try to stay in the lower bound. Smartphones have a low voltage cut-off point so the voltage doesn’t go dangerously low before powering off. With this in mind, I’m keeping my Galaxy S7 Edge between 20-60% most times, and try to avoid charging over 80% on my iPhone SE.

Pouly G said this: Some of you don’t understand meaning of term cycle. 1 cycle is a full discharge from 100% to 0%. So some of your math in Комментарии и мнения владельцев is wrong it should be like this: 100% DoD 300–500 50% DoD gives you 1,200–1,500 full 100% cycles meaning 2,400-3,000 50% charges. 25% DoD gives you 2,000–2,500 full 100% cycles meaning 8,000-10,0000 25% charges 10% DoD gives you 3,750–4,700 full 100% cycles 37,500-47,000 10% charges But it all comes down to Li-Po, Li-Ion batteries age really quickly. A 2 year old Li based battery is considered old doesn’t matter if you used it or not and probably is holding 80% of initial charge- At first I was confused as the table said discharge cycles, this implies that it is the amount of cycles when discharged by the DoD and fully charged to 4.2V. This results in 50% DoD giving the most cycles. HOWEVER THIS IS NOT TRUE. Paula is correct, according to the chart on http://www.mpoweruk.com/life.htm. the lower the Depth of Discharge, the higher the average cycle. Average cycle defined as a complete discharge and charge (0-100%). Roughly it seems halving the DoD gives twice the amount of cycles. This also seems correct with Table 2, going from 50% to 25% DoD roughly gives double the cycles, 1200 to 2000. Also Table 6 here seems to match with MrPowerUK and Tesla forums again, the lower the State of Charge after charging, the more cycles you will achieve. From what I read here and other studies I can conclude that it is best to make frequent, short charges, 10% or less ideally, and keep maximum charging voltage to a minimum. Though of course realistically that is difficult, it is better to do frequent top ups, and disconnect the charging as soon as possible, within reason.

Hello there. You mention that the battery is a 3.8 volts 250mAh cell but i think the 3.8 refers to the nominal voltage. Its a bit strange to be referenced as 3,8v because most of the cells i ve seen are referenced 3,6-3,7 but that being said i think its highly unlikely to be charged only until 3,8v. If i were the designer i would want the full 250mAh which is achieved at ~4.2. Therefore what i would do if i were you to increase the lifetime is make sure to charge it only at 80-90% and disconnect it afterwards, effectively restricting the charge to somewhere after 4.0v close to 4-05ish and i think this would extend the charge cycles but would reduce the RUNTIME between charging too.

I recently bought two smartwatches. Samsung Gear S2 Classic and S3 Classic and I am concerned about the lifespan of the batteries. I am not a science-minded person, so much of the article and nearly all of the Комментарии и мнения владельцев are a bit over my head. That said, from the information I have gathered from forums where I posted my question, I was led to believe that the battery should, in the end, last anywhere from 2-3 years, depending of course on usage, temperature, number of charge cycles, percentage of charge cycles, etc. One person stated that it sounded like the battery in the S2 looked to him to be a classic 300 cycle battery, so if fully discharged and recharged daily, it wouldn’t last a year! However, in the article above, it says: Most Li-ions charge to 4.20V/cell, and every reduction in peak charge voltage of 0.10V/cell is said to double the cycle life. For example, a lithium-ion cell charged to 4.20V/cell typically delivers 300–500 cycles. If charged to only 4.10V/cell, the life can be prolonged to 600–1,000 cycles; 4.0V/cell should deliver 1,200–2,000 and 3.90V/cell should provide 2,400–4,000 cycles. Given this info, since the battery in question (Gear S2 Classic) is a Li-ion 250 mAh 3.8 V 0.95Wh, which, I would assume, is close to the 3.90 V mentioned above, shouldn’t it provide roughly 2,4000-4,000 cycles, taking into account, of course, the variables I mentioned above? I would greatly appreciate any and all input regarding this questions, smartwatch batteries in general and those for the S2 Classic and S3 Classic in particular. Many thanks! John

Based on the information provided in this article, isn’t it the best practice to remove the battery for as long as you are home and let the laptop run solely from the power supply?Say that your battery is 50-60% drained or even 40% isnt it still better to save it from several hours everyday of being topped off as being in full charge stresses the cell a lot? You can always charge it when you wake up or at work depending on your schedule.This practice is employed on experia XE and newer smartphones too. They ry to avoid both toping off and complee draining based on the users lifestyle.

Hi Dominik, Nice idea on the hardware implementation. I checked out your website and I’m impressed. One question, on your test data, does 10% battery level mean 10% reported by the Android/iOS phone itself, or does it refer to a specific voltage? I think modern phones have a safe low level (cutting off early enough) so it doesn’t wear out the battery too much, but nobody knows for sure as they can mess with both the 0% and the 100% and make sacrifices on the usable life. Another question, is it capable of dealing with Qualcomm’s QC which raises the voltage to 9V? It’s still less than 1C charge rate on my Galaxy S7 Edge, so I think it’s ok as long as the heat is in check so I tend to use it when I’m in a hurry or have a fan to cool my phone while charging. Thanks, Hoon

Hello everyone, I have developed the Smart charging adapter which prolongs battery lifespan more than 2 times. It is called GentlyCharge and it solves problems of modern batteries like deep discharging and overcharging and protects battery from heat during charging. It is compatible with all the Android phones and tablets, and also with an Apple iPhone or an iPad. For more info visit: www.gentlycharge.com

Some of you don’t understand meaning of term cycle. 1 cycle is a full discharge from 100% to 0%. So some of your math in Комментарии и мнения владельцев is wrong it should be like this: 100% DoD 300–500 50% DoD gives you 1,200–1,500 full 100% cycles meaning 2,400-3,000 50% charges. 25% DoD gives you 2,000–2,500 full 100% cycles meaning 8,000-10,0000 25% charges 10% DoD gives you 3,750–4,700 full 100% cycles 37,500-47,000 10% charges But it all comes down to Li-Po, Li-Ion batteries age really quickly. A 2 year old Li based battery is considered old doesn’t matter if you used it or not and probably is holding 80% of initial charge.

My battery has that information. What it show? Are good on not? Why my battery dont charging (0%)? Battery:Battery Information Battery ID 1816Samsung SDIDELL KFHT82B Manufacturer Samsung SDI Serial Number 1816 Chemistry LION Long Term 1 Design Capacity 65490 Last Full Charge 65490

HELP. My battery for Dell 6230 dont charging (0%) and after the check show these: What is all of that ? I am litle unrelated. Is my battery DEAD. Power Efficiency Diagnostics Report Computer Name GEO1-PC Scan Time 2017-01-13T22:39:32Z Scan Duration 60 seconds System Manufacturer Dell Inc. System Product Name Latitude E6230 BIOS Date 10/08/2012 BIOS Version A06 OS Build 7601 Platform Role PlatformRoleMobile Plugged In true Process Count 95 Thread Count 1017 Report GUID 4c1be59a-4825-4928-86fe-85fb4c23ba61. Errors. USB Suspend:USB Device not Entering Suspend The USB device did not enter the Suspend state. Processor power management may be prevented if a USB device does not enter the Suspend state when not in use. Device Name USB Root Hub Host Controller ID PCI\\VEN_8086&DEV;_1E26 Host Controller Location PCI bus 0, device 29, function 0 Device ID USB\\VID_8086&PID;_1E26 Port Path USB Suspend:USB Device not Entering Suspend The USB device did not enter the Suspend state. Processor power management may be prevented if a USB device does not enter the Suspend state when not in use. Device Name USB Composite Device Host Controller ID PCI\\VEN_8086&DEV;_1E26 Host Controller Location PCI bus 0, device 29, function 0 Device ID USB\\VID_0A5C&PID;_5801 Port Path 1,8 USB Suspend:USB Device not Entering Suspend The USB device did not enter the Suspend state. Processor power management may be prevented if a USB device does not enter the Suspend state when not in use. Device Name Generic USB Hub Host Controller ID PCI\\VEN_8086&DEV;_1E26 Host Controller Location PCI bus 0, device 29, function 0 Device ID USB\\VID_8087&PID;_0024 Port Path 1 CPU Utilization:Processor utilization is high The average processor utilization during the trace was high. The system will consume less power when the average processor utilization is very low. Review processor utilization for individual processes to determine which applications and services contribute the most to total processor utilization. Average Utilization (%) 27.56 Platform Power Management Capabilities:PCI Express Active-State Power Management (ASPM) Disabled PCI Express Active-State Power Management (ASPM) has been disabled due to a known incompatibility with the hardware in this computer. Warnings. information.

is there any laptop battery with screw fitting that can be opened up to replace Li-ion batteries instead of throwing out the good electronic parts?

I’m suspicious of that information as it relates to LiFePO4 batteries. Their voltages are lower such that 3.92 is unachievable. Fully charged my batteries are only around 3.5 V. See page 2 here: http://www.a123systems.com/Collateral/Documents/English-US/A123 Systems ANR26650 Data Sheet.pdf. I haven’t looked at this in any detail but it seems to me that recommendations for optimum voltage for long storage life need to reference the specific type of battery instead of only stating lithium ion. This could be what is going on with your 58% vs 73% values.

The article states that the optimal charge level is 3.92 volts/cell and that 3.92 V represents 58% capacity. However, the company that manufacturers the charger I am using for my lithium ion pack (a Panasonic NCR18650GA type) says that 3.92 volts represents a 73% state of charge. Why the difference in percentages?

I use a custom battery pack on a motorcycle consisting of eight A123 (LiFePO4) cells in a series/parallel arrangement. I found that the bike’s ECM and instrument cluster will drain the pack in about 6 weeks of non-use so I’ve started making use of its quick disconnect. A Battery Tender Jr. will bring it up to about 14.2 V and it will drift down to about 14.1 V in several days while disconnected. Any drift beyond that seems to be very slow. The bike’s charging system will leave it at around 13.5 V, which is also associated with very slow downward drift while disconnected. All of that is at 65-70 °F. It’s relatively easy to drain the battery to a desired voltage. Do you have any recommendations on what it should be in terms of prolonging its life while in storage? P.S. The Dreamliner battery was a lithium cobalt oxide type.

Does anyone know what would happen to a Samsung phone which has 3000mah battery but was shipped with 0% battery and subsequently was stored in storage in warehouse for a year and the protection cut off switch was activated so did not turn on upon receiving. I think the voltage was around 3500mv so 3.5v at 0% maybe a bit less say 3.4v. how much damage to the lithium ion battery would their be if it’s been in storage at low voltage for a year brand new? Trying to decide whether to send it back. The voltage for my previous phone which i need to send back at 61% battery is 3920mv so 3.92V but on this one (due to damage i suspect of being stored at 0% and sleep switch activated ) at 61% reads 3855mv (3.85V) is the difference of 70mv (0.7V) a significant difference? It seems to me the damage caused by the sleep switch circuit activated for nearly a year in low state of charge will have damaged the cells in the battery right? Especially where everywhere preaches storing at 40%. I dont know why that Samsung factory is so stupid and storing it at 0% and sending the phones out that way.

What is the better practice for keeping battery well? We will do full charge and discharge to a certain level or always keep in AC power.

For what it’s worth, here is some experience that may be useful : We have designed an App for Android which turns the phone into a Time Reporting Terminal. We use the NFC capability as a Badge Reader. What this usage implies is that the phone will be connected 100% of the time to its charger. For the first batch of 100 units units we used a Samsung Core Prime phone. Well, after about 9 months in use, the batteries bloat to such en extent that the entire phone bends into an egg shape and we fear that some units are liable to explode. So we analyzed what actually happens between the phone and the battery. When the battery is fully charged, Samsung continues with a small trickle charge that starts at around 50 mA and drops off to 5. 10 mA (phone switched on, screen on and App running). After 40 minutes they disconnect the charger for around 4 minutes and then repeat the 40-minute cycle. The charge current is different with the phone switched off, on but idle, and on with screen on and App running. When you calculate the total charge into the battery during the 40 minutes and the charge drained during the 4 minutes you discover that the battery is being overcharged slightly with each cycle. When you extrapolate that over a month you discover that the overcharge is about 25% of the rated capacity of the battery (2000 mAh). So after 4 months the battery is overcharged by 100% and so it goes on until something (don’t yet know what) happens.

This got me thinking, which is worse for a sealed smartphone battery, keeping the battery full and plugged in most time when possible (with twice a day discharge to around 50%), or very frequent shallow cycling anywhere between 20-80%?

That’s a terrific tip Hoon, thank you! I studied a bit deeper hoping that common Mac hardware has general purpose access to that line such that software could control or influence it, thus allowing a software utility to control state of charge of the battery like the Sony Vaio and Lenovo ThinkPad, but evidently it doesn’t. Thus there appears to be no possible software means to control the battery’s charge level in a Mac due to lack of hardware support. Thus for maximum life management we must charge or discharge our Mac’s battery to about 58% and then insulate the MagSafe connector’s center pin when we’ll be on line power for extended periods, a stone knives and bear skins class primitive solution. Bitter bitter raspberries to Apple. I insulated my MagSafe 2 connector center pin for my MacBook Air 7,2 running Sierra 10.12.1, and your method does indeed work. However, the OS illustrates a lightning bolt over the battery icon at the top of the screen which suggests the battery is charging when in fact it isn’t. But the LED indicator in the mag-safe 2 connector remains dark. So the combination provides a positive indication. the icon can be interpreted to indicate that the laptop is receiving line power, and the dark MagSafe 2 LED interpreted to indicate that the battery is not charging. I tested one of my older MagSafe 1 equipped MacBook Pros running legacy OS 10.6.8, (for important legacy application compatibility) with basically the same positive results. The laptop is powered, but the MagSafe 1 connector’s LED remains dark and the battery doesn’t charge. The Finder’s battery icon has a lot of response latency, but ultimately (after a restart for me) indicates that power is connected and that the battery is not charging. But the Not Charging message overwrites the state of charge percentage information, alas, so the user has to refer to System Profiler / Power and do a little math to acquire that information. Or, for a rough indication, press the physical button for the battery charge state indicator to momentarily see it. I gather Windows 7 has provisions to control battery charge levels but they’re only effective when the system’s active. in sleep or shutdown mode those provisions can’t function, so the battery then charges to the level set by hardware (probably 4.2 V/cell or very close). Microsoft probably did the best they could but are handcuffed by their open hardware environment, and most hardware isn’t battery management enlightened. I haven’t studied the landscape in detail, but as far as I know the Sony Vaio and Lenovo ThinkPad are the only systems which provide truly enlightened battery management design and thus deserve hearty kudos. very good for them! They may rightly claim a far more advanced design in terms of battery management. The other vendors need to open their eyes and tend to their tardy homework. All just in my amateur opinions of course.

That’s a terrific tip Hoon, thank you! I studied a bit deeper hoping that common Mac hardware has general purpose access to that line such that software could control or influence it, thus allowing a utility to control state of charge of the battery like the Sony Vaio and Lenovo ThinkPad, but evidently it doesn’t. Thus there appears to be no possible software means to control the battery’s charge level in a Mac due to lack of hardware support. Bitter raspberries to Apple. Thus when we’ll be on line power for extended periods we must charge or discharge our Mac’s battery to about 58% and then insulate the mag-safe connector’s center pin, a stone knives and bear skins class primitive solution. Bitter bitter raspberries Apple. I gather Windows 7 has provisions to control battery charge levels but they’re only effective when the system’s active. in sleep or shutdown mode those provisions can’t function, so the battery then charges to the level set by hardware (probably 4.2 V/cell or very close). Microsoft probably did the best they could but are handcuffed by their open hardware environment, and most hardware isn’t battery management enlightened. I haven’t studied the landscape in detail, but as far as I know the Sony Vaio and Lenovo ThinkPad are the only systems which have truly enlightened battery management design and thus deserve hearty kudos. very good for them! They may rightly claim a far more advanced design in terms of battery management. The other vendors need to open their eyes and tend to their tardy homework. All just in my amateur opinions.

I just recently found that you can stop charging a MacBook that use Magsafe2 connector (probably same with Magsafe1) by blocking the center pin which is used for signaling. Had I known this, I would have used it like this for the last 3 years as most of the time I was on AC. Current cycle count is 100 on my late 2013 rMBP13. The battery still lasts pretty long (6 hours). I knew Thinkpads have a battery utility where you can limit the charge range by percentage.

Tom, I’m skeptical of Table 2 from the perspective of those who seek maximum lifespan (in total years of use) of their cells. Table 2 presents discharge data from a default charge voltage which isn’t stated, but I suspect is 4.20 V. (“DoD is assumed from a fully charged battery to said percentage level regardless of SoH.”) But charging to 4.20 V degrades the cell irrespective of depth of discharge. So my sense is that the data in Table 2 represents a mix of two degradation processes: Depth of discharge related degradation plus maximum charge related degradation. My sense from the public Комментарии и мнения владельцев is that most people seek to maximize the lifespan of their cells, or at least express that desire. Me too, even above total use (total of ‘units of use’, that is, sum of all depth of discharge times number of discharges). I want my portable devices to remain usable in portable mode for as many years as possible. Viewing the matter on a fundamental level, a cell has a primary electrochemical reaction, its charge / discharge reaction, which is 100% reversible and infinitely repeatable with no degradation. But alas there are also an array of independent secondary chemical and electrochemical reactions which cause degradation. They’re minimal at low temperatures and near the middle (ideally 58%) of the charge state. They’re stronger, and thus more damaging, at high temperatures and high or low charge states. So those who seek maximum lifespan in total years of use should keep their cells as cool as practical and as close to a 58% state of charge (3.92 V) as practical. I suspect it’s that simple. Or it should be. But the problem. a big one. is that most device manufacturers make such management extremely difficult (as a practical matter impossible) because they fail to provide a means to manage the peak charge voltage. (They also fail to provide a means to operate their fans more aggressively.) They’re immersed in competitive specsmanship, including portable use time, and highly resistant to anything they perceive might threaten their specsmanship posturing. However, clever engineers could convince their firm’s shallow minded MBAs that they can have it both ways. they can quote portable endurance based on 4.20 V charging in their specs, yet provide a utility which allows users to manage their cells for maximum lifespan by lowering the default 4.20 V peak charge voltage to more lifespan friendly levels, including of course 3.92 V. Evidently a very rare few do. in his February 28, 2011 comment above Rob Smith advised that his Sony VAIO laptop provides such a utility (except that it evidently presents charge level information as percent of capacity rather than voltage). Big kudos for Sony! But availability of such control should be pervasive rather than rare. Bitter raspberries to the majority of vendors. We consumers need to pressure vendors to provide a utility like Sony’s in all their portable products. We should aggressively demand it. And vote with our purchase dollars whenever an opportunity arises. In the meantime I hope a Battery University member will conduct a precision test focused on conditions for maximum lifespan. In particular I’m very interested in capacity endurance for cells cycled between 58% charge (3.92 V) to 48%, 38%, 28%, 18%, and 8% charge. At 23 °C and, if time permits, some lower and higher temperatures too. I’m very interested in lifespan results under those conditions, and suspect many others are too. Again I’m not a student of energy storage cell technology. These are just my personal impressions.

Hi there, What is the safe range of SOC for large scale Li-ion battery energy storage system 2 MW-4 MWhr ? I found most of the literature assume a range between 30%

Bruce Campbell, The data doesn’t seem to match the conclusions of the article. Referring to Table 2 Assuming a 10% DoD gives you 1 unit of use and you can recharge it 4700 times you’ve gotten 4700 units of use out of the battery. Now if you have a 25% DoD you get 2.5 units of use per recharge. You can recharge it 2500 times you’ve now gotten 6250 units of use from the battery. If you have a 50% DoD you now get 5 units of use per recharge. You can recharge it 1500 times you’ve now gotten 7500 units of use from the battery. If you have a 100% DoD you’ve now gotten 10 units of use per recharge. You can recharge it 500 times you’ve now gotten 5000 units of use from the battery. In addition keeping the battery topped off is contradictory to the information contained in Table 3. I’ve found I obtain the best life and length of use between charges by allowing the battery to discharge till the device tells me it needs to be recharged, and then recharging it at that time.

Also: In the Macintosh world a third party free or contribution ware utility called “MacsFanControl” is available. I have several fan equipped Macintosh devices which all utilize MacsFanControl at its highest cooling settings (which are far more aggressive than Mac OS defaults). My fans thus make more noise and drain my battery faster. But they keep my systems quite cool, which I view as far more important. Maybe a similar utility is available for other devices. Thermal physics is very clear about heat. it degrades systems, including electrochemical and electronic. As best I recall, roughly speaking every 10 °C rise decreases life by about 50%. that is, life is halved. Heat kills. So I prefer to keep my systems as cool as I can. (Even when I must thus discharge my battery a bit more deeply, to a point.) (BatteryUniversity.com: If you think my thoughts in this or my previous comment are of some benefit feel free to utilize them as you please, except that if you quote me directly, please attribute me responsibly.)

The article seems to explain matters exceptionally well to me. But highly effective communication is a terribly daunting challenge. even excellent composition can partially fail to convey information well, especially when complicated subjects are involved. I’m not a student of energy cell (battery) technology, so please don’t confuse me with an expert. But the article seems quite clear to me, so the following is an effort to express some key points in an alternative way in the hope that they’ll be more clear. Beware though. I won’t try to cover everything. As the article said: “Most Li-ions charge to 4.20V/cell, and every reduction in peak charge voltage of 0.10V/cell is said to double the cycle life.” and “In terms of longevity, the optimal charge voltage is 3.92V/cell. Battery experts believe that this threshold eliminates all voltage-related stresses; going lower may not gain further benefits but induce other [degradation processes].” (The actual quote was “symptoms”, but my sense is that degradation processes is more accurate language.) And “The smaller the discharge (low DoD), the longer the battery will last.” A dominant theme in these public Комментарии и мнения владельцев seems to be a desire for maximum cell life management. Me too. I want my cells to remain healthy for as many years as possible, and that’s usually much more important to me than availability of full capacity. Here’s the unfortunate rub: Due to marketing related specsmanship pressures, cell management systems (charging and other management circuits) have different priorities. Portable use time specs are a major competitive matter. device manufacturers seek to publish superior use time specs, so they’re inclined to design their cell management systems to charge to about 4.2 V. That seems to be contrary to our actual desires, and for inaccessible cells such as in most portable devices there’s little or nothing we can do about the charging voltage, alas. Hopefully insightful engineers will eventually provide a utility in a device’s operating system which will allow us to select our own desired peak charging voltage within a range of 3.92 V/cell to 4.20 V/cell. (Frankly this should have been implemented in all significant portable devices years ago.) As the article states temperature is also a major degradation factor. (And not just for the cells, but the electronics in the device too.) Per the article: “The worst situation is keeping a fully charged battery at elevated temperatures.” But lower temperatures prolong life under all other conditions too. Other degradation processes take place at low states of charge. just as the cell encounters degradation processes at high voltages, it encounters other degradation processes at low states of charge. In my personal estimation middle range charge and discharge cycle stresses degrade much less than higher temperatures, higher charge voltages, or deeper discharges. So for longest overall life, keep the cells as reasonably cool as practical, charge them to 3.92 V/cell, and discharge them as minimally as practical. recharge them to 3.92 V/cell as quickly after use as practical. You have some control over temperature and depth of discharge. As to charging voltage, we all need to pressure vendors to provide charging voltage control in their products. They can do this, and rather easily, but evidently need tangible consumer pressure to prompt action. Be bold. advise them clearly that you want this, are significantly displeased that it’s not yet available, and will purchase from whichever vendor first provides this capability. For accessible cells such as in common LED flashlights, you might have full control, or nearly so. Ideally find a charger with a selectable charging voltage, if such a product exists, and set it to 3.92 V. If not, and you have some electronics technical skill, modify the best charger you can find to reduce its charging voltage to 3.92 V. (Or construct your own. fabricate a high precision current limited regulator circuit with a very precise 3.92 V output. Which, ideally, fully disconnects from the cell about five minutes after 3.92 V is achieved. Very inexpensive (roughly 3) power converter modules which provide both current and voltage regulation are readily available from Chinese and perhaps other vendors for example.) Multi-cell batteries, such as in laptop computers, present more challenges. But just as with portable devices, we consumers should demand that vendors provide charge voltage control from 3.92 to 4.20 V/cell. Again, they could. and rather easily. But they probably won’t until significant pressure to do so exists. In the meantime we can keep our systems as cool as practical, and discharge the battery as minimally as practical during portable use. Again, I’m not an expert in these matters. I’m just trying to articulate my personal understanding.

my old smartphones lithium ion battery takes 24 hrs to charge fully and in some case charge remains constant.what should i do please advise.will it explode

Can anyone please please answer the most asked but never really answered question here? a) Shall I keep my laptop/smartphone (in my case surface pro 4, so taking battery out is not possible) plugged in while I’m for example at home/office or b) is it better to prolong battery life by using it until XX%? and charge it again to YY%? If b) please also tell us the XX and YY percentages. Thanks a lot!

One follow-up question to my questions above: When Table 2 refers to a depth of discharge of 100%, what voltage level is that? We know from this article that full is something like 4.2V or 4.35V. But what is empty? Is it the 3.0V at which some equipment shuts down? Is it the 2.5V–2.7V at which the battery permanently goes to sleep? Something else? I noted last night that just before my iPhone powered down the voltage was 3.5V. At that voltage the indicator was reporting 1% capacity. So is 3.5V a 99% DoD? I doubt it. Perhaps some device manufacturers are preventing deep discharges, so the advice to not discharge too far may need to be taken with a grain of salt if you’re using a device that has already taken this into account. Finally, it would be good to know which is most damaging: Full charges or full discharges (and here I don’t mean full discharges below 3.0V; I mean full discharges as reported by a piece of consumer electronics). I expect it’s full charges. But there is insufficient information here to know whether it’s better to cycle a phone or a laptop from 90% to 40%, or from 80% to 30%, or something else. (And it’s further complicated by the fact that 30% as reported by the device may not actually be a 70% DoD (see my comment above about the voltage at which your device reports 0%).

I continue to be confused by the author’s DoD table, even after reading many of the related Комментарии и мнения владельцев above. Does the depth of discharge refer to how much of the battery’s capacity is used up, or to the absolute charge level? In other words, what is the depth of discharge when I go from 75% charge to 25% charge? Is it 50% or 25%? In the same article it says that the ideal charge voltage is 3.92V, representing a capacity of 58%. So does that mean we should be cycling our batteries between 58% and 50%? It can’t be right to recommend that we only use 8% of the battery’s design capacity. Historically I have got excellent life from my laptop and iPhone batteries when cycling between about 75%–80% and 20%–25%. But should I instead be cycling between 90% and 40%? Or something else? Also, I assume that when Table 2 gives 1,200–1,500 cycles for a 50% DoD, that isn’t full cycles but just number of charges, right? I.e, if one cycle is defined as one discharge and recharge of the entire capacity of the battery (or, say, using 50% of the capacity twice), then I assume the correct way to interpret table 2 is that you get 300–500 full cycles with a 100% DoD, but 600–750 full cycles with a 50% DoD, right?

I have just bought a Powerguard Notebook protector chargeall which the salesman insisted prolongs the life of a battery for iPhone, tablet, laptop etc. He was very persuasive and assured me that charging any of these devices using this device which seems to be some sort of surge protector would virtually double the life of the batteries. I haven’t opened the packaging yet but have read through as much as I could of the very helpful information on this site but cannot see any mention of these supposedly marvellous inventions. Can anyone enlighten me please. Have I been had? Or will this little intermediary between device and power source really extend the battery life? Thanks in advance.

I recently purchase chainsaw that uses 80 volt and 40 volt lithium batteries need any and all help in regards to keeping these usable

Thanks for the information! I used a laptop 12 cells of each 1200mAh, 3.7v to build power bank.The cells were stalked in parallel. I charged it with a laptop charged output of 19.5v, 3.33A. I monitor it to avoid over charging. Sir, my question is this is there any ‘gauge’ or IC that I can add to the charger to shot down current entering the battery to avoid the same over charging when the battery is full. over, circuit is needed? I am an amateur in this filed. Please I need a solution. Thank you once again!

Thank you for the excellent information. It would be useful to see an article about the effect of high charge rates on battery life.


Battery charger designers generally have only limited knowledge about battery technology, and design chargers according to their beliefs and assumptions. They are inclined to be overconfident and arrogant about their technical prowess, assuming batteries to be electrochemical devices in need of rescue and assistance by electronics experts.

In early 2015, I purchased a Novatel T1114 Wi-Fi hot spot with Voice router (Verizon), it uses a Lith-ion cell for operating the voice telephone segment during power outages. I used the device normally for about 5 months, then, knowing it would be put into temperature controlled storage while I relocated, I disconnected the Lith-ion cell from the T114 so as to minimize self discharge. When I disconnected it, the battery should have been as near to 100% charge as the T1114’s internal charge circuit could have done. A year after putting the T1114 into that temperature controlled storage, I put it all back together (correctly) and fired it up. No joy, the T1114 declares ‘no battery’ and immediately shuts down. I’ll have to get a voltmeter to test the cell, but I’m guessing that during storage, the cell somehow self discharged to zero volts, despite being disconnected from the T1114 (there is a third wire coming from the cell package, probably a thermal circuit uses the battery and outputs temperature data on the third wire). I’m also guessing that the T1114 charge controller is not a well fleshed out design, being incapable of recovering this cell from this state of discharge. Note that the T1114 uses the battery for times when AC power has failed; in my neck of the woods, AC power goes out for several days at a stretch about every 18 months or so. This further indicates that the designer of the charge cicuit should have reasonably expected the cell to completely discharge. Sigh. I miss working in power conversion design development. I would have had the designers head for missing this condition. The cell is made by Palladium Energy, no obvious results on Google. Oh well, at least it has a class designation of ICR19/66, and thus it might be available off the shelf. Maybe that online battery retailer. Would love to jump charge it with a different battery pack for a few seconds, in hopes of getting the terminal voltage high enough that the T1114 stops treating it as ‘no battery’; I’m thinking that if there was voltage at the packs terminals, the T1114 might resume operation and also resume charging the battery. Otherwise, until the T1114 recognizes a battery, it will refuse to boot, it will shut down, and. for want of a nail, the kingdom was lost, so to speak.

@Kad: The smartphone chargers don’t charge the smartphones battery, that job is done by the smartphone. The chargers output 5V because that is the USB standard (actually it allows for 4.75 to 5.25V). The smartphone is the one that limits both battery charging current and voltage. If the charger says 1.0A, that is the maximum current it is designed to deliver, but that doesn’t mean the smartphone will send that much to the battery. @Alex: First of all, a bare solar panel will deliver a voltage that is dependant on both the amount of solar radiation hitting it AND the amount of current being consumed by the load. If there is no load or a very little load, you can get 50% higher voltage, meaning under no circumstances are you to connect a solar panel directly to a lithium battery. If the battery is full and there is still solar light, it will continue to charge the batterty. To get the longest life cycle, do as the article says and lower the maximum charge voltage and increase the llow voltage cut-off voltage. There are chips that will let you program both voltages, or use fixed voltage parts accordingly. Or you can switch to LiFePO4 chemistry if your circuit can handle the lower voltages.

You don’t need to remove the battery, because it doesn’t charge when full. Keep an eye on temperature. the most evil for batteries. If you play games, better to do this without battery. But if you use notebook for taping, and frequently move between room, houses. leave it in case. It is designed to be used, not stored ) 2. No need to put it in a freezer or something. battery degrades by itself. After 3-4 years it will loose half of life. 3. Yes, charge it to 75% level, because internal schematics draw energy. Li-ion element by itself has very low self-discharge rate, but not charging scheme. After half of year it will discharge to lowest level, and even can die. So charge it sometimes, if you desided to store it (again. no point in doing this)

Hi, I got all day researching for the better strategy to take care of my laptop batery and I have some questions to make, if anyone can answer it would be good: 1. Can I remove my battery for 3 hours and then put it back without any damage to the same? I work all day at home and my laptop keeps plugged all day on AC charge 2. If I remove my battery should I put inside something to protect more? Like put inside a drawer? 3. Before remove my battery, do I need to charge him between 40%~70%?

What is the mathematical relation between No. of Charge Cycle and Life time estimation of Li-ion Battery? e.g. for NiMH batery Lt = Lt (New) if C=300 charge cycle 1.3. 0.001C. Lt(New ) if C300 charge cycle I want this kind of relation for Li-ion Battery.

The article and Комментарии и мнения владельцев are really helpfull but i’m having trouble concluding how to care for my battery. I just bought an Asus X555LJ with not-removable LiPoly battery and i’d like to extend as possible it’s battery lifespan (as is the firs thing that declined of my previous, adorable, 5 year old Toshiba Satellite, all from misuse). Long story short, what exactly should I do: a) Never let it go under 40% or over 70%//40%-80%//20%-80%// 50%-80% b) Keep it between 70% and 90-95%? c) keep it always plugged when possible (i understand not)

I’d like to use a couple of 18650 batties in a small hobby kit with a small solar panel that will always remain on and transmitting data. What would increase battery longevity most? 1) Using a charge controller and a 5V solar panel. thus fully charging the batteries each sunny day 2) Using no charge controller and a 4V solar panel. thus never fully charging the batteries and having my voltage float up and down each day (never a complete cycle) Naturally both would need over discharge protection. I guess the question is whether to use a TP4056 with 5V solar or just go with 4V solar and no TP4056

I don’t get one thing (don’t laugh, I’m as far from understanding physics as one can) I don’t get. How come, that almost all smartphone chargers (verified randomly 3 at home) have an output of 5V and 1.0A, while my battery clearly states, Limited Charge Voltage 4.35V,? The charger only reach peak voltage when fully charging the battery?

Patrick, The battery has to be fully drained and then fully charged. The time it will take depends on: 1) Current charge % of battery. 2) Maximum discharge current of both the charger and the battery 3) Maximum charge current of both the carger and the battery 4) Battery capacity. Plus, for calibration purposes, it might discharge/charge at a lower rate, or at a higher rate to test for temperature dependency, and it might do the full discharge/charge cycle more than once.

So all the IMPRES charger is doing with the Li-Ion batteries is recalibrating the fuel gauge? It sure does take a long time when it conditions.

=Mara If you have a typical charger it will work at any voltage from 90V (Japan) to 240V (much of Europe) so it will ride through voltage sags and spikes OK. A surge protector will make it more resilient to voltage spikes.

Patrick, First of all, IMPRES batteries come in different flavours: NiCd, NiMH, Li-Ion. http://www.motorolasolutions.com/en_us/products/two-way-radio-accessories/batteries/impres.html Contrary to NiCd and NiMH, there is no such conditioning needed for the Li-Ion batteries nor does it present any advantage to the battery capacity. For Li-Ion, all that it really does is recalibrate the battery fuel gauge, which is an IC embedded in the battery pack that tracks battery capactiy. Usually this is accomplished with a coulomb counter which tracks the amount of current that has been charged/discharged from the battery. The propietary algorithms refer to the use of voltage and temperature measurements (and impedance tracking algorithms) in addition to the coulomb counter to more accurately predict battery total and current capacity. This is also the real reason cell phone and battery manufacturers still tell you to let the battery charge completely before the first use. It’s not for conditioning like the old NiCd and NiMH batteries, but to let the battery fuel gauge be properly calibrated.

I’m traveling to a country with frequent power outages and changes in power supply. I am worried that the variation and peaks in power will damage the battery of my laptop. How can I avoid this? I already use a surge protector but I think this only works in case of extreme peaks, right? Thanks!!

This article seems to be from 2010. Motorola now uses IMPRES chargers on their portable radios with Li-Ion batteries to condition the batteries every so often by fully cycling them (full discharge followed by full charge). I’m guessing Li-Ion battery research has changed the way we treat Li-Ion batteries in the last 6 years?

It is clear from the figure that relation between charging cycle and capacity is linear for a specific charging/discharging rate. Now I am confused here how the measurements are done. Say battery capacity is 1500mAh and after few charging cycles with charging/discharging at 1C, they capacity is 1400mAh. 1C is equivalent to 1500 mA. Now since the capacity is reduced 1C is not equivalent 1500 mA anymore. Do the above measurements should be interpreted accordingly? Any reference is appreciated.

1) Can someone give more info about Bayu’s question and Michal’s response? 2) Ideally, to what DoD should I let my cell phone drain to before I charge it again to 100%? 3) Is keeping my cell phone plugged in after it’s been charged to 100% a good practice, both from the standpoint of extending battery lifetime and safety? (I’m extrapolating to cell phone batteries the paragraph stating that unplugging laptop batteries from AC grid is unnecessary and keeping it plugged in is safe). Thanks! On September 15, 2015 at 11:55pm Bayu Murti wrote: Actually I’m little bit confused with that DoD theory. Given that 100% lasts a day, if we apply 100% DoD, then we’ll get 300-500 charging cycles, means 300-500 days. If we apply 10% DoD, we’ll det 3750-4700 charging cycles, but we also need to charge our phone 10 times a day, means we’ll get only 375-470 days. Where is the differences? On October 8, 2015 at 2:15am Michal wrote: @Bayu Murti: Well the thing is that one charging cycle is defined for whole capacity of battery, that means if you discharge your battery to 50 %DoD and then fully charge it two times. it is count as one charge cycle. Theoretically discharging to 10% of DoD in your case can be done 10 times and that is count as one charge cycle.

Anyone here noticed that this comment thread has been active since 2010? That is crazy. But even crazier is the subject of the article that has racked up idk how many actual Комментарии и мнения владельцев but for sure approximately 6 years worth And they’re all about BATTERIES! I WTF! DERP/DURP from back in 2010, if you’re out there,feel ya.

Question on using Li-ion battery for industry use as back-up battery. If the battery is just charge up and sit there without discharging it, it is used for backup in-case of power outage. How long will the battery life last? Longer or shorter life than applying the discharge method? So, base on this article, if we keep the voltage at about 3.92, it should prolong the battery life. Correct? Ted

i`v got newly launched Galaxy S7 with Li-Ion battery. It`s habit for me to charge to 100% even when i had another phones with Li-Poly i`v did same. but this one is expensive piece of glass so i`m wondering about that. Apple done some trick to preserve cycling, i believe Samsung would`v done same but. how safe is to charge my battery from 25-30% to 100%, will this decrease lifespan a lot? and what is recommended range of charging for S7`s kind of battery? Thanks in advanced

@sakthivel: There’s a multitude of different li-ion battery chemistries, each with different maximum and minimum voltages, ranging from 2.5-1.5v for LTO (Lithium Titanate) all the way to Li-CoO2-NMC with 4.35-3.0v. Electric vehicles often use a combination of two or more different chemistries, to achieve both high-current and high-capacity benefits. Modern cellphones typically have 4.35v as their 100% voltage and go down to about 3.4v as 0% (which is probably more of a phone’s electronics limitation than a battery limitation per se). Numbers cited in this article are probably for the original implementations of Lithium Cobalt Oxide (LiCoO2), which goes from 4.2v to 3.0v. Whether the same suggestions for prolonging battery life apply to other chemistries is a question I don’t know the answer to, but if I had to guess, I’d say they probably do.

For a LI-ion battery. what is the operating voltage range.(100% means = what is the voltage range and for 0% = what is the voltage )

the charger for my lithium battery (for my golf cart) has a red light when charging and green when fully charged. it was supplied with the battery. it is now showing the green light, but not charging. the battery is usually never run down completely, nor charged fully. it has had about 170 of these cycles, i.e. about twice per week. the make is ULTRA MAX, bought from AMAZON. I don’t know much about batteries and would be grateful for your expert advice

I have a Toshiba Satellite L50-A-161 with a Li-ion battery. The removal of my Toshiba battery is quite complicated: it is necessary to open the case unscrewing 14 screws and remove the dvd unit. The battery itself is fixed to the motherboard with 4 screws and a pin connector. https://www.YouTube.com/watch?v=IG0lW7t92bI This kind of notebook was plainly designed to prevent the user from removing the battery. Knowing this, my main concern is that I need to use my notebook for a prolonged period of time, many hours a day, often from morning to night, and I rarely need the battery as source of power, working in places where the AC power is always available. To some extent I mainly use the battery as an AC filter. With this in mind, I am wondering what practice suits me best: keep the laptop connected to the AC grid and calibrate the battery once a month with occasional partial discharges/charges would be safe? You wrote that Most users do not remove the AC power, and this practice is safe, but of course this goes against the Partial charge better than a full charge guidance rule: keeping the laptop connected to the AC grid would keep the battery always at 100% charge.

Very informative page. I remember many years ago when electric cars were in dipers (late 90’s?), reading an article that to maximize life, they would only have the battery charged up to 60% and discharged down to 40%, but I don’t remember which chemistry they were using at that time. Rest assured that electri car maker are making everyting to prolong battery life without the user having to watch for battery voltages. The most they will let you do is select between optimize for runtime and optimize for battery life. I bought my Dell Laptop with the extended battery on Dic 2010. The original capacity was about 9.8Ah. The battery has been used and abused. I’ve had it stay at maximum charge for ages, I’ve it cycle from 7% to 100% constantly, I even have had it shutting down due to overheating several times. After 6 years it still holds more tha than 6.8 Ah. Runtime has gone down from about 3.5 hours to about 2.2 hours. I’ve never seen another notebook battery last as long as this one. My wife’s notebook is not quite as old and is already on its third battery. I’ve a questionabout that doubling of lifetime for each 0.1/V lower top voltage. Say you have a battery with an original 1000mAh capacity. If I lower the charging voltage to 4.1 its starting capacity should be around 840mAh. Now for the lifetime calculation, what is the end of life capacity used? Is it 70% of 1000mAh or 70% of 840mAh? In my opinion, doubling the lifetime should mean doubling the time it takes for the battery to drop down to 700mAh of usable capacity. However I’ve seen (on other cources) that they use 70% of the new starting capacity, as for 3.9V the starting capacity is already far below 70% but they claim a 8x cycle life. To me this is nonsense, because at 4.1V, 19% new capacity loss is already below 700mAh (81% of 86% is below 70%). It also means that supposing a linear loss of capacity (for clarity), it is only by the time a 4.2V charged battery reaches 750mAh capacity that it would have less capacity than a 4.1V charged battery which would have fallen to 752mAh. This also means that for the first 83% of the charging cycles, a 4.2V charging voltage would have provided more capacity than a 4.1V charging voltage. @Tom Wiersma: Electric bike batteries are normally made up of LiFePO4 lithium ion cells. The advantage is that you can put them in series to directly replace lead-acid batteries, and charge them with standard lead-acid battery chargers. The Rapid loss of capacity in these battery packs is however due to a completely unrelated factor: cell unbalance. Unless you use a balancing charger, little differences in internal resistance between cells will keep growing the unbalancing problem. The charger stops charging when the most charged cell is at maximum voltaje, and protection circuitry within the battery pack or the bike will stop discharging when the lower cell is at its cutoff voltage. Balance charge your battery pack and it will probably go back up to nearly 20 miles again. Life cycle in LiFePO4 are much higher than other lithium chemistries, about 1000-2000 cycles.

Hi. Thank you for this informative page. I dont understand the table 4; many car manufactors like Tesla and Kia let the car charge the battery cells to about 4,3V. Wouldent this destroy the EV battery within about 2 years? Best regards Arnfinn

Hey guys. Is it okay to leave the laptop plugged in. I pretty much use it as a desktop. Means its almost always connected to the AC power and runs 15 hrs daily. I have limited the charge level to 50% and leave it plugged it. And once in a while when there’s a power cut i let the battery discharge to 7% ( which is the default setting it came with before it would ask to to connect to a power source) And Once in a few months i discharge it down to 7% and then charge it up all the way to 100%. and then remove the battery and leave it out for 6-12 hrs before i put it back on my laptop and then discharge it down to 50% and leave it plugged in. as mentioned earlier. So is it okay to do the above routine? Is it really okay to leave it plugged in at 50% almost all the time.?

I would recommend reading the following article, lots of interesting facts which will probably answer your question about the 7KW Powerwall batteries. http://www.catalyticengineering.com/top-ten-facts-about-teslas-350kwh-powerwall-battery/

How much of the 7kw-hr Powerwall can one discharge before significantly limiting the battery’s number of cycles? Thank you

Amy standard commercial battery operated device would have these safety features built in and can be seen as miniature circuit boards when disassembling a battery pack. What I am referring to in my previous note was the use of just the actual cells from for example s laptop or similar type of battery pack. These Li-ion cells would not normally be protected from either overcharge or over discharge when used for other purposes than originally designed for. I have purchased a Nitecore D4 battery charger (recommended) which will ensure the proper charging cycle but am still missing a suitable discharge protection.

I have a Galaxy note 4 mobile. I didn’t understand about the correct battery percentage to plug my mobile in to the charger and correct percentage to discharge it from charger. can you please tell me the best healthy percentages.

Many articles are written about charging Li-on batteries, but I am surprised nobody seems to have come up with a method of safeguarding against over discharge. When I used to condition Ni-cad batteries, I built a recycler which used relays to automatically cut off the charging and discharging cycles. This was so simple, after finding suitable relays that would release the holding coil when the voltage dropped below the desired level. This should be even easier with Li-on batteries, seeing that their voltage is much easier to match with a 6 or 12 volt relay. Does anyone have any smarter methods of easily controlling the usable voltage level? It needs to be dead simple so that each separate battery could be protected, i.e. Using 4 ex laptop Li-on cells in a 12v drill battery case.

Great write up BUT I still don’t know if a new phone battery needs to be fully charged from the beginning or not. If its not fully charged then will the memory and life of the battery be affected (diminished)? These are points I would have appreciated knowing about at the beginning of the article rather than slogging through rheams of data (which I appreciate) but honestly do not have time to read through 🙂

All (nearly) very useful (especially Alice). I have a lot of experience with large lead-acid batteries (from Submarines) but most does not translate here to Li-on. I am just getting a BMW i3 (without backup generator) and am keen to maximise life and range. The car comes with monitoring but no voltage information so I will look for a way to see this. Range is around 120Km, but expect to be used for around 320-40km a day. Will follow the guidance above and on charge when down to 50% (where possible). If anyone has an i3 info or advice I would like to hear it. thanks.

I am having a problem with the battery life of my Samsung Galaxy pro tablet. It`s not charging while I am using you tube although the sign of charging is showing it is charging but the percentage of charge keeps decreasing. but if I stop using the tablets it gets charged. please can you help me solve this problem because if I am watching a film I can`t just stop it and carry on watching it few hours later. kindest regards. Naima

I use my laptop mostly at home. Does it mean it’s optimal to keep the charger plugged in all the time (since the more shallow the discharge, the better. so by extrapolation, the most shallow discharge. no discharge, would be the best)

PLS my HP laptop battery even when fully charge will not power on my laptop or any other laptop unless made active by just charging it for few seconds(sometimes 3sec), and its last for 3hours when fully charged. what can i do to stop this?

Hello, I sell batteries in Holland to customers and the most asked question is why the battery needs to be 40% charged for storage. Every resaler tell this to their customers, but this bulletin gaves me the best oppertunity. Storage is best at 3.92 volt 58% SoC. I appreciated it that this bulletin gave me the best answer. Also for my electric bike is this the best SoC to maintain capacity at a prolonged period. Thanks BU and Cadex for this usefull information. I like that. [my English is not so good, sorry]

Hi, I would like to know whether a Li-ion battery in a laptop if leaked due to exposure to heat, will it discharge acid / will the discharge from the battery be acidic and corrosive such that it damages the motherboard or chips. Thanks Regards, KPR

The practical sweet spot seems to be 4.1v and dont top up if you don’t have to. After 500-1000 full charges, you will be sick of the battery, given improved cells over time. Given that, perhaps out batteries ought be say 26v or 38v etc., and our chargers set to charge.1v lower.to give a net 24 or 36v. The article concurs with what I hear from cruising yachties. Keep them between 20 and 80% charge, and they last forever. I also hear flattening the battery isnt so bad. Its storing them flat that’s the problem. Put a flat battery on charge immediately you get home and its tolerable practice.

@Bayu Murti: Well the thing is that one charging cycle is defined for whole capacity of battery, that means if you discharge your battery to 50 %DoD and then fully charge it two times. it is count as one charge cycle. Theoretically discharging to 10% of DoD in your case can be done 10 times and that is count as one charge cycle.

Actually I’m little bit confused with that DoD theory. Given that 100% lasts a day, if we apply 100% DoD, then we’ll get 300-500 charging cycles, means 300-500 days. If we apply 10% DoD, we’ll det 3750-4700 charging cycles, but we also need to charge our phone 10 times a day, means we’ll get only 375-470 days. Where is the differences?

I just wanted to know the shelf life, like can I buy two batteries, use one, save the other? or will the unused one get old? I spent wanna read a physics paper

i charge my battery when it is 1% 2 % and charge up to 5% 6% and use it because i need. i do it maybe 5 times every day for months. it is no problem for me now.

Do the Комментарии и мнения владельцев and suggestions of this article also apply to AGM (acid glass mat) and SLA (sealed lead acid) batteries used in UPS’s (uninterruptible power supplies) or those used in power wheel chairs?

The dispute whether to keep the battery permanently attached to the notebook, thereby providing flexibility and protection against power outages, or to store it half charged, thereby greatly improving the battery’s lifespan, can easily be resolved if one has a fresh and a worn down battery. I simply leave the old battery, which is below 10% capacity but still holds more than sufficient power for finishing some tasks and providing hibernation power, permanantly connected to the notebook and keep the new battery tucked away after charging it to 60%. If I plan to use my notebook on battery, it suffices to connect the battery to the computer for one hour in order to charge it to 95%, but even if I don’t have the time to top it up, it still provides at least 50% capacity and a decent runtime.

We are very disappointed in the lithium ion life we experienced on two different bike batteries. While initial life produced a range up to 20 miles on our 24 volt emoto bikes, that range degraded to 1 mile after 2 years on the first bike, and the second bike is now at 8 mile maximum after 22 months and degrading rapidly. The bikes are stored indoors with periodic charging in winter and are recharged after each use in summer. The factory that made the batteries is out of business, and a rebuild costs 300 a piece. We have 1200 total in the two bikes new. The first sat around Menards till I purchased it for 400. It short life lead us to believe shelf life was a factor. On the second bike we had to wait for the factory to produce the batter! Same results. Could have been worse. It could have been a 35,000 lithium ion car!

Interesting. I have an e-bike with a lithium battery. After commuter cycling on it for 27 months (year round), it’s still as good as when I got it (actually, better since getting a new console which seems to be more efficient at extracting energy from the battery). I only discharge it 50-75% per trip before recharging (50% in summer, 75% in winter. cold weather does seem to consume more energy out of the battery). So from above, this battery should last a goof 5-7 years. far more than the 1 year the manufacture’s warranty! However, I do hear of people who don’t use their ebikes having problematic batteries from the get go. which would make sense as the charge does dissipate with time if I don’t ride it (usually within a month) so I presume that that would be equal to a full discharge. Must be said not having trickle charge on the charger also doesn’t help. if I put the plug in on Friday and don’t pull it out to Monday, I’ve lost 20% of my charge!

Andy. I am not going to join this discussion about lithium ion but I think I might be able to throw some light on the lead-acid situation. A lead-acid battery that isn’t receiving any charge for a month, and is probably being drained slowly by the electronics in the car, will likely have been reduced to between 60 and 80% state of charge. Starting an engine that has been standing takes more out of the battery. The alternator voltage regulator will limit the charging voltage to a maximum of 14.4 volts. It is impossible to bring a 12V lead-acid battery that has been subjected to this form of treatment to a full state of charge with a normal average trip. The battery begins the next month of inactivity in a partial state of charge. Each successive month will deprive the battery of charge. After a few months of this kind of treatment the battery will give up the ghost. There are trickle chargers on the market that begin charging the battery until the voltage has risen to well beyond 14.4 and then drop the voltage to about 13.5 and hold it there. Batteries thus maintained last eight years or more.

You are definitely right in this regard that it is problematic but it is not limited to lithium. Batteries are an inherently weak technology that struggles to keep up to the demands of the power consumption in wake of constantly evolving technology. Lithium technology is already considered a mature battery technology and almost at capacity of what it can be capable of and further advancements are slow and progress is minimal until we can switch to another type of battery. For your typical lead-acid car battery, taking an inactive car out once in a while is actually beneficial for its health since when a lead acid battery is partially discharged, lead sulfate forms. This sulfation causes a permanent loss of capacity of the battery. So the batteries should only be stored in a fully charged condition and the charge should be topped up from time to time by taking the car out to charge it with the alternator to compensate for the self discharge of the cells.

Andy, If removing the battery is the Smart thing to do, then perhaps a woman could provide an optimum solution. A plug-in extension cord arrangement that would have the battery out of the oppressively hot laptop and at the same time fulfilling it primary function. (By the way, taking a car that is very infrequently used, for a run once a month is a battery killer.) To sum up, lithium is a SERIOUSLY problematic technology.

Alice, this is only recommended as a measure if you don’t need portability or are not doing anything important on your device that needs a backup power supply. And like any car owner, they should take the inactive car out once a month to ensure the battery doesn’t completely go dead. With OEM laptop battery replacement packs at times costing an arm and a leg and manufacturer customer service being so poor in general, it’s only an ideal suggestion and does not represent what the typical user must do. We all make sacrifices to the detriment of the battery and that’s okay because it is meant to be used. But I have to admit at the very least, removing your battery while plugged in is a Smart thing to do. In my experience with laptops, especially high performance aluminum or full-bodied metallic laptops heat up considerably, and the heat conducts to the battery along with heat from charging combine to easily equal 50-60c. An excellent example would be the first few generations of HP Envy laptops notoriously known for heat and cooking the battery. Under heavy use while plugged in with the battery fully charged, these batteries typically did not last more than a little over a year without holding any useful amount of charge and most definitely needed replacing soon after.

Andy, Brilliant idea! Or is it? Have you not worked out that your suggestion is more or less the same as buying an expensive automobile, locking it up in the garage and using buses and trains for transport instead? Much, much later, there is a emergency and you need the car in a hurry. And guess what? You have a flat battery, flat tires and find the rats made their nests out of the bits and pieces that used to make the car go.

Adding to what I missed above: When you are planning to store your batteries, charge the battery between 45% and 65% to compensate for gradual discharging and depending on how long you plan to store your batteries for. Make sure you take them out once in a while (every month, few months or so) to check they still have charge in them and charge them back up to storage capacity if they are too low. It goes without saying that you don’t store a battery with 15% or less battery or you could risk it going into sleep mode or being too weak/damaged to charge.

From all the information I’ve gathered over time, this is what I really recommend: Remove your Li-Ion battery if you don’t need portability or are not doing anything important on your device (if you don’t need backup power in case of a power outage). This prevents ambient temperature and heat from the device from degrading your battery much much faster than as it would be on the shelf. Just run the device directly from the charger if it allows. If you want to take it a step further or for longer-term storage, you can tape the terminal of the battery with electrical tape (to prevent accidental conduction and short circuits) and store it in a sealed ziplock bag inside your fridge (to prevent moisture). NOT YOUR FREEZER. The idea is to keep it just above freezing temperature but not to freeze your battery. 5 degrees Celsius is a good temperature. As for charging and typical usage or If you have a hard-to-remove internal battery, try to keep your battery level from 30% to 80%, hence charging only 50% of the battery at a time. In other words, not too low and not too high battery capacity and not too short and not too long charging cycles. By doing this, you also follow the 50%DoD in this article that appears to statistically give the most hours of use for a Lit-Ion battery. On a side note, when you buy a new battery, the first 3-4 charge cycles are very likely going to give you a lower total capacity than what the battery is capable of, but this should be amended after about 10 cycles. I don’t recommend fully discharging and charging your batteries for these first few times to prime your battery, just use it normally unless your battery percentage meter is inaccurate and needs to be calibrated then do a full cycle.

I think you’re confusing charge levels with depth-of-discharge. 50%DoD just means the capacity level to which you would discharge your battery below the ‘original’ capacity. For e.g. Say a battery has a capacity of 10,000 mAh. Discharging it to 5,000 mAh(50% charge) is 50% DoD, so is discharging from 7,500 mAh (75% charge) to 2,500 mAh (25% charge). The author isn’t being contradictory, don’t fully charge it (maybe charge to 75% Charge) and don’t discharge it completely before recharging (75% to 25% charge, i.e. 50% DoD).

@TT Martin: We need to clea what is 1 discharge cycle? (Ans: 1 dis.cycle = 4 x 25%DoD = 2 x 50%DoD. etc.)

MARTIN ? The electrochemistry that relates cycling to DoD in batteries is not linear. The only way to obtain that information is by hands-on testing.

@Alice Referring to Table 2 Assuming a 10% DoD gives you 1 unit of use and you can recharge it 4700 times you’ve gotten 4700 units of use out of the battery. Now if you have a 25% DoD you get 2.5 units of use per recharge. You can recharge it 2500 times you’ve now gotten 6250 units of use from the battery. If you have a 50% DoD you now get 5 units of use per recharge. You can recharge it 1500 times you’ve now gotten 7500 units of use from the battery. If you have a 100% DoD you’ve now gotten 10 units of use per recharge. You can recharge it 500 times you’ve now gotten 5000 units of use from the battery. In addition keeping the battery topped off is contradictory to the information contained in Table 3. Good data in the article, but, poor interpretation of the data by the author. I’ve found I obtain the best life and length of use between charges by allowing the battery to discharge till the device tells me it needs to be recharged, and then recharging it at that time.

MARTIN, Can you explain how one might charge at a higher level of discharge? You probably don’t want to acknowledge that people with less knowledge compensate by making more rude noise.

So they are arguing that if you charge your battery at a higher level of discharge, the phone will have a higher cycle life. WELL DUH. if you divide the 10% DOD by 10 you actually only get 470 total cycles out of each 100% that it drained. Which it actually below the maximum suggested charge cycles for charging at 100%DOD. Now if you look at the 50% DOD cycles and calculate the cycle it gets per 100% then you will get 750 max. So is it suggesting we charge our phones at 50% ? LOL wtf is this non sense it may reduce the possbiility to temperture wear to the battery however, charging for shorter period of times

After reading through this article, I went and did some measurements on some of the phones I own. I basically did a full charge, waited for about 5 minutes, pulled out the battery and measured with my multimeter. On a Samsung Galaxy Note 3, it seems to go upto about 4.3 V. On a Lenovo A606, It goes to about 4.21 while on my old Nokia 1110, it seems to stop at 3.8 V. I also did a comparison of actual voltage measurements against the readings I get from battery apps. They’re pretty close ( ~. 0.01V) and also require a certain ‘settling’ time.before the readings stabilize. I guess it’s a trend here that modern phones tax the battery a lot. So, it’s no surprise that they lose quite a lot of the capacity within the first year of usage. Maybe the best approach is to only charge our phones to about 75% or so and stop.

I’ve read this article and others and have scanned all Комментарии и мнения владельцев here and read many. But I still haven’t found a recommendation or what seems to be a simple and obvious question. maybe it’s above and I missed it. Here’s the question. My laptop is always connected to the power grid except when I travel. However I do move it between my office and my deck and don’t want the hassle of shutting down between those moves so my battery remains in my laptop at all times. I saw the recommendation in the article to let it discharge only to 50% before recharging. At least I think that’s what I read. My questions is, how often should I let it discharge at all? Once a day? Once a week? Once a month? Thanks in advance for any knowledgeable answers.

ok, now you are talking. thanx for informations, means a lot to community. Need to ask: does it apply to smartphones as for laptops you said?

peter, You said they were wrong, gave an opinion, did not explain, were not constructive. Lithium ion, like all batteries should be charged at constant current, up to a suitable preset voltage. Impossible with computer directly in parallel with battery, computer drawing variable current. Simple solution, in common use by circuit designers who understand batteries. Feed computer directly and feed battery via simple current sensor. The current sensor output is compared to a reference value. The difference between the two is used to correct any error in the current and can maintain an exact charging current value. The end-of-charge voltage can be preset to optimized values that will terminate charging a desired state-of-charge.

I apologize if this has been asked or answered but if one using a laptop, as a desktop should take out the battery, store it safely but use it once every 2 weeks or so, what do you do if the laptop wont allow you to take out the battery and you use it as a desktop? T.I.A.

Everything is in my post, there is no need to repeat it again. But you didnt explain delivering power separately. Explain? Link? Pdf? Please be constructive as others are.

peter, You accused two people of being wrong. It is easy to drag information from source. Anyone can do it. Means nothing. Opinions vary. Can you explain why these two people are wrong?

information and advice about turning of device while charging is from this site. And we are discussing it very precisely what are the facts from theory and how is it in practise. also, please give us info and any valid link about delivering power separately to the rest of the system while charging li-ion battery. thanx

peter, The reason why most people pay good money is to use what you disparagingly call the parasitic load, as and when they want. Look ma, my battery lasted ten years. I achieved this by hardly ever using the computer. It is as easy as 11 for a charger to read the battery, look after the battery, and at the same time deliver power separately to the rest of the system.

It is obvious like 11, i dont wannt to be smartass but please, read this article(s), see the tables best is charging @ 50%DoD. best is charging while device is turned Off A device should be turned off while charging. This allows the battery to reach the threshold voltage unhindered and reach a low saturation current when full. A parasitic load confuses the charger. batteryuniversity.com/learn/article/charging_lithium_ion_batteries

i think edward is wrong: 10-90% charging/discharging is not the best way to prolong battery life. Also i think feanor is wrong: using device while charging is not good for battery life coz battery is making a lot of micro cycles and wearing battery.

John, thanks for the feedback, appreciated. Would you have any recommendation on where to buy one? Or even a shop that deals in this kind of thing? Peter

Peter. There are so many variables in batteries and battery usage, it is impossible to achieve with any reasonable degree of accuracy, what you say you want to do. Having said that, there are such systems on the market, because demand, not technology, drives these kinds of things. Battery purchasers look for the lowest possible price. Hence battery manufacturers are obliged to manufacture to the lowest acceptable standards. Batteries are a grudge buy. There is nothing that can be made that cannot be made by another more cheaply. This has been the driving force over the last 40 years in an industry that is 130 years old. The only place you can find quality is on the sales brochures. Hence some batteries will last eight years, some will last four years, some will last two years.

I wondering if anyone could recommend where you could buy a Battery Management System BMS for a 36v electric bike battery which can be plugged into the battery for diagnostics; to read recharge cycles, kms distances etc. Your article and discussions on DoD is interesting, to work out the number of DoD vs kms travelled and to try and work out the lifecycle capacity left on a battery and the kms remaining to be run. Thanks Peter Baillie

There is sentence: The shorter the discharge (low DoD), the longer the battery will last. In table 2 they said if 10%DoD then 3750 cycles. We know that one cycle in this case is 10x10DoD. Maybe we should charge battery more often than 50%DoD.

I was about to post my reasoning that based on Table 2 it would appear that charging at 50% DoD is the sweet spot. Then I saw that Richard Coleman had reached a similar conclusion. What I found interesting is that frequent recharging when DoD is at 10% appears to be almost as bad as waiting until the battery is fully discharged. Thanks

Is there any stand alone appliance that can be used to protect a battery from exceeding a 50%DoD for gel batteries?

Question: In table 2, the cycles and DoD relationship seem to imply that 50% discharge is ideal. Reasoning is that for e.g., 50% DoD, you must charge twice as many times as 100%, therefore to make the two operating schemes comparable, you must divide the apparent cycle life by two, i.e., you really got the equivalent number of 675 full cycles. If you adjust the data in this way, the graph seems to peak at about 50% (I fit a 2nd order polynomial to the adjusted cycles. I’m still reading this article. so there may be something I missed. Glad to discuss, please email me with contact information if possible. I have an MS in Operations Research and a BS in Naval Engineering, so I’m not just flailing here. but I may be wrong.

i agree! where is the short simple answer? what i’ve understood is this and i’m not even sure its correct. you buy a new laptop. after turning on discharge to 10%, recharge fully to 100% form there on. discharge to no further then 40%, recharge no further than 80% once a month. discharge to 10% and then recharge to 100%. repeat cycle! Could anyone please confirm this? Great info and all but jeeeez! can there not be a more concise version for people that actually want to play with their new toy, like, today without the stress of damaging it?

I have a 4400mAh Li-Ion laptop battery from Batteries Plus. It is model: RAYCL2809B, it is made by Rayovac. This battery works well but only as long as I do not allow it to fully discharge. If it fully discharges, then the charger is not able to recharge the battery. I have tested the charger with my friend’s battery (he has the same laptop but with the original battery) and it works just fine. The guys at BatteriesPlus also tested the charger and said it was fine. Anyway, whenever the battery fully discharges, I have to take the battery back to BatteriesPlus and they hook it up to a machine for like 8 hours in order to revive it. Anyone know why this happens to the battery? It is quite annoying that I have to keep going back to the store to get this rayovac battery revived. Anyone have a method to revive the battery at home?

i am using my laptop with Li-ion battery 6 cell for almost 3 years and its battery power is as good as new what i do is always plug in my laptop in trust worthy power source like UPS (urgent power supply) and keep using it on it and take out my battery hence i am saving my battery charge cycles that the secret

I’m still confused as to when and how much to charge my battery in my MacBook Pro. Is there no simple answer? (1) Charge it 4 hours every day (2) only charge it when it dies and stops functioning. (3) Keep the charger on all the time. (4) Never worry about it. (5) Use it plugged in until the battery dies! (6) See why I’m still confused.

This piece of information helped me a lot.I used to charge my tablet at 7v/cell but now I know that I should charge It at only 4.20v/cell.Thanks a lot.

Simple question: How much time battery(2080mAH) take for fully charged? charger:5.0v=550mA (50/50Hz 0.2A)

Why should we users bother on these details?? Don’t you think its wisest move to implement the optimum cut-off circuit in the laptop itself by the manufacturers in order to maximize the battery life?

Thanks Edward. I don’t think that the article is clear on this point though. Cycle is at one point (if not here, then elsewhere) defined as 0-100%, and the article goes on about how reducing depth of discharge (DoD) will increase cycle count. But if we’re counting a cycle as charging from any DoD to 100% then it achieves nothing and all the discussion about DoD us pointless. Most consumers don’t need to worry about over-discharge as the equipment (mobile phone, laptop, etc) will prevent that unless they store their batteries for weeks or months at 0%.

Feanor, the 4700 figure means a) 4700 charge cycles from 90% to 100%, if you charge from 90% to 100% and then discharge from 100% to 90% you can use 4700 cycles. yes the a no increase the total discharge time in theory, but in fact. you can hard to control the 0% to 100% charge and discharge, discharge to 0% maybe means over-discharge. anyway, it is a battery ,do not too worry about the cycle life. just use it

Luca. no; you’re better to use the device while it’s being charged, as this reduces battery use and wear. With one caveat though. you shouldn’t leave the device on charge all the time; normal use for a portable device is to disconnect it for at least a few hours a day when you move it around, so I generally stick to that. Just use it normally, but avoid excess charging or excess use (unless your usage pattern requires excess use, then use it. it’s a tool, after all!).

Hi Edward. I don’t understand your response. I’m not sure I was clear myself though. My question is, whether the 4700 figure means a) 4700 charge cycles from 90% to 100%, or b) whether it means 1 charge cycle = 10 cycles from 90% to 100%, in which case the battery would last 47 000 charge cycles from 90% to 100%. Both seem unlikely to me; a) would provide no increase in battery cycle life, which goes against what’s been said, while b) seems excessive but meets the definition given of one charge cycle being 0-100%.

These type of posts are forever. Battery saving tricks are always welcome. We often ignore basic things and we have to repent for those. Follow the video http://vimeo.com/65740042

Is it worse for a lithium polymer battery (phone or laptop) to be charged while the device is on? I would think yes, but I am not sure.

I assume that the number of charge cycles in the table above are complete charge-discharge cycles? So, for a 10% depth of discharge, the battery should last for 4700 FULL recharge cycles. not 4700 recharge cycles of just 10%?

Dear Rich, If the Ipod battery is not used for a long period, it should be replenish charging one time for every six month. zzrm316@163.com

I just bought an iPod classic after the discontinuation, and I already have a working one, so I just want to store this one until its needed. How long is it ok to just leave it in the box? I read once that you’re not supposed to let a battery sit with no charge in it, and the date on the iPod box says 2009, meaning this thing almost definitely has no charge right? Should I start it on charge cycles or just leave it in the box?

Thank you for answering edward. Also, i’ve observed that everytime i charge i use DU Battery APP and when it charges for like 40mins or so, the voltage im seeing is above 4.20. And its advisable to have lower than 4.20 right? What should i about it? Or is the app accurate?

Okay, so im trying if someone can answer my question (by reading the Комментарии и мнения владельцев from above. yes from 2010 Комментарии и мнения владельцев) and still i was not able to get any answer. My question is. What is the ideal charging percentage for my 2110mAh Li-Poly battery (From a smartphone, nondetachable) Is it discharing to 25% and charging to 90%? Or 10% to 80%/90%? Thank you in advanced for answering.

mark paulo yan.-the output voltage from USB is 5.0V ,and the lithium-ion max voltage is 4.2V, this because there is overcharge circuit in the lithium-ion battery to prevent from overing 4.2V. to charge the battery, the output voltage must higher than the battery max voltage. is that clear

Looking for some clarity regarding the tests on Depth of Discharge (DoD). Is the voltage level 0.0V at 0% DoD? If so, perhaps a more realistic test would be discharging to a typical device’s cutoff voltage (say, 2.5V).

I’ve read the article mostly and searched the page for USB, for related info. I did not, however read all the Комментарии и мнения владельцев, which are quite a lot. Now my concern is that to my undertanding Li-ion batteries charge well in the 3.9 to 4.2 Voltz range, whilst USB ports have a 5V rating, which is way higher than the recomended 4.2V. Does newer/current (2014) devices have voltages regulating circuits? Or does current Li-ion batteries operate on 5V? Or are we mangling our batteries using current common charging ways?

Fascinating, the underlying principle I found from reading this article is do not go to the extremes and stay balanced, reduce stress, prolong the life and avoid high temperature. Applicable to many other aspects of life.

Dear Mohamed. no minimum amount requirement, for example, 10% discharge is not equal to one full discharge, and 10 times 10% discharge is equal to one full discharge. please email to me zzrm316@163.com for detail information Edward

thanks Edward, and what should be the minimum amount to which we are suppose to drain battery to prolong its life

Dear Khayyam, how long do you keep this smartphone?? two years or three years? please email to me zzrm316@163.com Edward rechargeable boy

Another thing is that it drains power mostly in stand by. When I listen to walkman, watch videos or work on Wi-Fi, it works like before and only little charge is used mostly 2%-7% is used.

I have a smartphone with li-ion battery. It’s Sony Xperia SP and it has built-in battery. First it was great but then because of that useless battery doctor task killing app, one night I left my mobile with 22% charge left and tomorrow when I woke up, it was 0%. Since then I feel like my mobile battery is not good. My habit is to charge mobile when it is below 15% and I never plug it out until its 100%. Last night at 4am I left it on stand by with 72% and today in the morning it was below 58%. There was only one message and the notification light was turned off in the settings. What should I do?

Looking for table number 3, can I say that the best way to use your batteries is discharge them normally (80/85%) and then charge them back just a few hours before using them again?

It souds as if the best bet is to use an old battery that holds 50-70% charge for home use, when plugged into the mains. This will protect you from power outages etc, Then put in your nice new 100% chargeable battery when travelling and you need to be working umplugged.

Dear Youngjae Cho ,different Lithium battery from different company have different performance. we need test the discharge curve to get the answer more details please contact zzrm316@163.com

You doing office work or watching movies surfing net, better detach the battery but if you doing games or other heavy grahic duties attach the batt and turn of all conservative modes and let the machine flows.

great resource, thanks for all the info have a quick question, if any gurus have an opinion it would be greatly appreciated just got a Levono Z710 ideapad and it came with Energy Manager software that has a conservation mode. from what the software says, it is intended to be used if you’re not going to be using the laptop for a week or longer, to keep the battery at a state of charge of 55%. 60% to avoid battery life reduction due to long periods of full charge state. when i turn it on and use the laptop, the battery charges to: 60% available (plugged in, not charging) so my question is, would this not be the best way to use my laptop while at home and AC is available (95% of the time), and turn conservation mode off and fully charge the laptop when I’m actually taking it somewhere AC is not available?

My hp625 battery never gather heat because it is full charged and conected to the wall socket, do not place the machine on carpet, clothes or such stuff that cover fan holes. off course discharging ages the battery

Thank You for responding. As I understand the heat produced by keeping the battery in full charge condition is less harmful for battery health than charging and discharging of the li-ion battery each time?

Hi Mehdy As the battery can not be removed never let it go below 80% or gradualy it will get old, you use it at home right? so why not plugged in while in home Everyone knows that battery killers are charge and discharge plus heat 🙂 live happy homie

Hi, I purchased a laptop computer with embedded battery (the battery can’t be removed) and I’m wondering if I need to calibrate the battery or not? The seller told me that it is needed and I have to discharge and charge it 3 times in order to be calibrated (I do it once till now). Another issue: do you recommend keeping the battery charge in 40% or it’s not necessary? My laptop computer will turn off by 7% of battery charge (my experience of first discharge). I use my laptop most of the time at home. Which strategy best maintain my battery health? My laptop name: Sony VAIO Fit 15 SVF15A18CX Battery Type : Standard Lithium Ion Battery (VGP-BPS34 3650mAh) Battery Life : Up to 3 hours and 45 minutes10 Thanks.

hi should i remove my hp625 battery while gaming or watching movies, the indicator says not charging when the battery reaches its full condition and i heard that if you remove battery it will cause damage to laptop while in serius actions that need some extra power and actually the battery can work as an back up power to save hardwares

Great article and a lot of good info in the discussion. While I know next to nothing compared to a lot here I just had to jump in wth my thoughts. When you consider the cost versus the lifetime of these packs they are not that expensive, baby them and get say 12 months against using them without worrying about longevity, but not abusing them, and getting 9 months, say you pay 60 for the battery, thats 5 a month babying against 6.66 a month without worrying, is all the fuss worth 1.66 a month ? I use 16650 3000mah batteries in high powered modded led flashlights, they are always fully charged when not in use, often have 3A or 4A load on them, never taken below 2.8 v although sometimes taken to 3v, the lights get hot, the battery compartment sometimes getting to 50c or so, is this abuse, you bet, will it shorten there lifespan, yes, but I am prepared to put up with it to follow this hobby, what I am getting at is sometimes you just have to do what you have to do, and if that means discharging the batteries until you laptop tells you they are flat, then just accept you have shortened the life of the battery a tiny little bit and move on. I am in no way putting down anyone here, treat them nice and they last longer, of special interest to myself was not leaving a laptop pack out of the laptop for more than about a month, my wife has two packs and she just leaves one pack out fully charged until she needs it, not now she won’t 🙂 Cheers David

For my new laptop, I want to maximize its battery capacity so that when i have a big trip, i can make the most out of a full charge. Based on this article i am wondering which of these two methods would work best (unless i am wrong either way). 1. I keep battery between 40 and 70 percent charge all the time. My reasoning is that I want to keep the voltage per cell low by not charging it too high, and I want to make the depth of discharge as low as possible since i will be using it at home and will always have a charger available. 2. Keep battery between 20 and 50 percent same logic, but I think keeping the voltage even lower by not charging my laptop above 50 percent will also help improve battery life I am also wondering if even doing a cycle between 20 and 80 percent charge would be significant enough to increase battery life. I have an Acer V7. 482PG-6629

Yes, partial discharge is better than full discharge, but also partial charge (meaning. not fully charging the battery) is better than full charge. Keeping the battery always at full charge and especially plugged on a charger for long time will shorten it’s life. http://j.gs/3HYu

I have a new Asus s400 ultrabook. It has a built-in battery so removal is not an option. I have read that partial discharges are the best for longevity of the battery. So my question is do I use the laptop on battery till it drops to about 70% battery life and then plug in and top it up. Do I use this method unless I need to be away from ac power.?I want to do the best for the battery. Thanks

I have a Asus laptop and it’s advertised battery backup time is ~ 3-4 hours. However I have got more than 9 hours of battery backup. No I am not kidding. This was when I used my laptop somewhat sparingly and did this on purpose to find out the maximum battery backup. My settings. 1. Display is always 0, the lowest brightness possible. The background is full black, screensaver is full black, browser background is full black. In general in every software if it is possible to have total pitch black background I go for it. Actually it looks very sleek and you may not recognize it is the same as your usual softwares. I do it primarily yo save my eyes [oh yes, i love my eyes more that the environment] but it also prolongs battery life. 2. when running on battery, my processor is underclocked to 60%. 3. my laptop is set to switch the display off after 1 minute. the laptop itself never sleeps or hibernates. i dont like to wait for my machine to switch on if i resume my work. the HDD is put to sleep after 20 minutes of inactivity. 4. my laptop is NEVER switched off. this one is about 6 months old and I have switched it off for more than an hour only 3-4 times. over it is permanently connected to the AC power. so far my laptop has run on battery (for more than a couple of hours) only twice in the last six months. the result is that my battery is almost as good as new. any battery shows strength decay only after about 100 discharge cycles. mine has been to only (maximum) five discharge cycles and I intend to keep it that way. no wonder I get such a long backup.

Nice Tips! Look, you must Dim your screen – Most laptops come with the ability to dim your laptop screen. Some even come with ways to modify CPU and cooling performance. Cut them down to the lowest level you can tolerate to squeeze out some extra battery juice.http://www.stensly.com/2013/12/how-to-extend-battery-life-of-your-laptop.html

Very good to know that keeping LiIon batteries at full charge is actually not a good idea. I always thought, keep them all as full as possible to storage. but now I know I’d rather not do that anymore. I also didn’t know that higher temperatures are that bad for LiIon batteries. and I always wondered why notebook batteries die relatively quickly coompared to other batteries, like in camcorders. It really is a shame that no notebook manufacturer has a 50% charge option. It would still be good enough to use as a ups in case of a power outage, but the battery could last for 5 years or even more. But when you look at the for original spare batteries, I guess that is why they won’t do it. Rather make some dough on spare batteries every two years.

I bought a tab with lithium polymer battery one part of the article stated charging it to lower voltage will extend battery life. is it good to charge at 75% or 80% I can compromise with battery run time but cannot with its lifespan. I have battery vehicle too and any suggestions are appreciated.

This article sais: Environmental conditions, and not cycling alone, are a key ingredient to longevity, and the worst situation is keeping a fully charged battery at elevated temperatures. This is the case when running a laptop off the power grid. Under these conditions, a battery will typically last for about two years, whether cycled or not. But what’s worse, running your laptop of the power grid (thus having a fully charged bettery) or stop charing when it’s at 80%, drain it to 30-40% and charge again? I’m asking because in when you run it of the grid, the battery becomes warm whilst being full. When not running of the power grid, you’re causing another cycle, and it only has a limited amount of cycles. What’s the ‘least’ bad for my battery?

My Samsung NC10 netbook when new ran on battery for 4 hours and 20 minutes. After three and a half years it still gave 3 hours and 30 minutes on battery. Hardly ever used on charger. The BatteryBar app showed 28% wear after around 1500 charge cycles. Is this battery exceptional?

From a pure engineering perspective, your point is taken. However, many of the people here are seeking practical ways to extend the life of their batteries. The extreme example is if you never discharge the battery, it should last forever. Not only is this untrue, it also completely defeats the purpose of having a portable device in the first place. I believe the misunderstanding may lie in the definition of a cycle; even the author points out that there is disagreement among experts. How many of us have had the experience of “taking care of “ a battery by keeping it constantly charged only to discover the capacity of the battery has diminished rapidly anyway? I think there are other factors that may override the basics of DOD and total number of cycles. In one of these articles the author points out that the worst thing you can do to your battery is to use it while you are charging, yet that is what most of us are constantly doing with a cell phone; It gets low on charge, and you still need to use it, so you plug it in and continue your conversation. The author suggests that this induces many tiny cycles of charge/discharge, in turn creating lots of heat, which might account for the shortened battery life over time.

I still dont understand why any of the people above still hav’nt understood what the author means be a cycle. If DOD is 10% (100% to 90%) it constitute only 0.1 cycle and not 1 full cycle. So only by doing that 10 times will make a cycle. So total energy produced during the battery’s lifetime will be 100 times compared to 100% DOD. I hope atleast some of you are able to understand this now.

I have recently bought an iPad. I would like someone to tell me how to keep it in optimum performance, in particular the battery. Thanks.

I went through this article its true. being an electronics Engineer. it is well known that charging and discharging are Properties of a battery. but I had experienced I used my laptop HP mostly on AC. I still even after 50 months m getting 35 minutes battery back up. My ColleaguE s use their laptop on charging and disparaging process their batteries dies in just around 30months so s prefer to use it on ac but must be aware of heating phenomena. I tired it on my Samsung Smart phone too it is giving back same when I buyed it 1 year ago. so nothing harm on using your li battery until it heats up thanks for this superb analysis.

I have a question. I see lot of experts here, I would be thankfull if someone can answer this question. I am using a Mobile Device Sony Xperia Tipo inside the Bus and it has to be kept permanently charged as we are using its Bluetooth capability. Will there be any safety problem related to this use, I would be using it 24×7 and the mobile would always be connected to the charger. Please assist with your valuable feedback/Комментарии и мнения владельцев/suggestion Rupesh

Fred- I think this is the site: http://www.batteryreview.info/ I purchased 2 of the Gorilla Gadgets high capacity for the Galaxy S3. I hated running from charger to charger. Now I have one in the phone, which averages about 3 days with my usage, and I carry the other charged one and simply change out. I don’t ever use the charger that connects to the phone-just a cube-style charger that plugs in to the wall; leave it overnight, and then take it with me. I have concluded that the whole idea of obtaining maximum life and output is not as relevant as reliability and consistency- realistically nobody keeps devices that long any more. I probably throw away devices that have better batteries in them than what I was getting brand new 10 years ago. I love this site, I wish there was a more active discussion forum. There are a lot of Smart people who visit here.

Thanks John. sort of what I’m thinking too (blowing smoke and delay tactic). I do have, and have used, a fast discharger, but they chew up the phone and still make it unavailable for hours, and really heat it up. so I’m looking for a kinder way (as my previous Galaxy S2 died and I think part may be to trying this in the past to many batteries). it is a LOT harder on the phone than the batteries! If you happen to be able to locate that blog, what would be helpful (but only if easy for you to find). many thanks. good site, this one.

There are some free Aps you can get which will discharge the batteries for you, so I would recommend doing that instead of the science lab version; although you can certainly connect them to a resistor and discharge manually. My own opinion is that whoever sold you these is blowing smoke to stall you and prevent you from asking for a refund. I have heard mixed opinions both here and other places about the validity of exercising a lithium battery, but the technique suggested to you sounds more like a NiCad strategy to me. I can’t find the link right now, but there is a guy who has a pretty good blog dedicated to reviewing the various replacement batteries out there. Maybe you can do a search and locate it. He has found that many, many of them are lying about the actual capacity of the cells. So what you have may be a decent quality battery, but it does not have the claimed capacity.

I recently purchased 6 Li-Ion batteries for our 2 Samsung Galaxy Note 2 Phablets, and the batteries only get 50-75% of what the OEM 3100mAh batteries that came with the phone, yet they rate their batteries at 3500mAh. I complained, and they told me to fully charge and discharge 5-6 times as this would improve the capacity. This will take me a long time to cycle through all of my batteries in this fashion. Are they BSing me or can this be true. Also, if possibility of being true (from what I’m reading here, that should not be the case) is there a good way to discharge them faster (eg rig up something with a resistor so I don’t need to run my phone through all of these exercises??

I have seen that most Li-ion are charged to 3.7V. I have an application which requires 3.9-4V. Would anybody supply me a battery and charger charged to 3.9V-4V?

To: Walt Borntrager Your statement about lithium ion memory has been backed up by some research. http://www.nature.com/nmat/journal/v12/n6/full/nmat3623.html Here we report a memory effect in LiFePO4—one of the materials used for the positive electrode in Li-ion batteries—that appears already after only one cycle of partial charge and discharge It doesn’t say it’s ruined, but it remembers a partial charge. after one cycle.

I must say the Galaxy S3 battery must be leaps and bounds ahead of the information here and on wikipedia. I have discharged my battery below 5% about 10 times in the first 3 weeks and let it run to 0% twice. I have now taken steps to charge the battery at about 30%. However, the battery monitor pro app currently estimates it’s capacity as 2143mah so doesn’t seem to have affected it. The spare battery (official GS3 accessories pack) has only lost 4% power after 1.5 months of storage time starting on 100%. What I’d like more information about is table 3 because I dislike what is being said there and the numbers look suspicious relative to the words. Surely the battery does not lose 20% of its maximum capacity permanently after 3 months if it is sitting at 100% and 25 degrees? I mean if the spare GS3 battery only lost 4% temporarily (ie. can be recovered via charging), surely it has not lost 15% permanently in just 1.5 months. If this statement was true then spare batteries can only ever have 40% of the original maximum capacity if stored at 100% for a year.

The study shows that 10% and 25% depth of discharge was not as good as 50% (table 2) but would have liked to see the 75% and 90% depth of discharge data as those would be more practical options. That is noone is going to regularly recharge battery at 90% charge or even 75% charge. It would be useful to know whether to target a recharge at 50% or would recharging at 25% charge or 10% charge be even better or substantially worse? Alex

I am using a Nikon Coolpix 8700 camera. The camera came with a 7.4v 700 mAh battery. I need replacement batteries. I see batteries advertised at anywhere from 700.1500 mAh. I was told that due to the physical size of the battery it cannot be manufactured with greater than 800 mAh. I understand how to prolong the battery life (I suppose it wouldn’t hurt to put them into a refrigerator or surround them with a cold blue ice back). Is the information I received correct (re: mAh) or should I attempt to purchase a battery with the highest possible rating?

Many Li-ion batteries will hold charge and maintain their performance for a decade or more. If you’ve read everything on this forum you should have enough info to keep your spare battery good for many years. I would summarize it as: keep the battery in a cool place, charge it once, discharge it to 40-50% charge, and then leave it alone until you need it DL

I just purchased a cell phone and was wondering if I purchased a replacement battery but never charged it keeping as a spare would this be possible or do Lithium Ion batteries degrade with non use. The phone is an off brand and I am worried when the original batteries loses storage capacity I may not be able to find a replacement. Thanks for your great informative website.

For desktop UPS use in a laptop, you probably want to maximise your battery years by charging only to 3.92v, which corresponds to 50% charge. For portable use, you just want to recharge to 50% if it gives you enuff life, or whatever level does give you enough life. Ideally, a battery management program would allow several charging targets:. MAX portable runtime (ie, 100%). UPS use (eg, as desktop computer or low-usage phone days) (3.92v or 50%). several steps in between MAX and UPS for flexibility. My Dell 5720 laptop has a desktop usage charging scheme which keeps the charge between 70 80%

Not such great news. Same lithium ion battery manufacturer, batteries fitted to Mitsubishi electric cars. Caught fire, at least one car totally destroyed. Simple problem organization with vested interests facility to hide behind lawyers = next to zero problem solving capacity.

@Avi: If you read the article above, you will see a Depth of Discharge (DoD) table with the following information: 100% DoD 300 – 500 50% DoD 1,200 – 1,500 Fudging the numbers in the table, you can get: 90% DoD 480. 700 80% DoD 560. 900 And so on. Based on that, I suggest you do not let your battery drop lower than 30%. In addition, if possible do not charge your battery to 100%.

Great news! Boeing sorted out their lithium ion battery problem. They seemed to have brushed the engineers aside, proudly brought in a team of legal-minded johnnies, who proceeded to tell everyone they had known about the problem since 2008, just did not use that solution because the paperwork was out of sequence.

Samsung Galaxy Note II has a 3100mAH Li-ion battery. Some Internet sites suggest charging the battery when it reaches 10%, while other sites suggest connecting the charger when it reaches 50%. any ideas which might be correct? Thanks!

Thanks for the good advice. I have a question if the laptop battery runs out very quickly (3-4 min), this means that it is already broken, and yet somehow you can recalibrate it, fix it?

So many Комментарии и мнения владельцев, so could you add the last date of the original, so that we can avoid reading old Комментарии и мнения владельцев? In case not covered: 1) Battery charger sometimes breaks e.g. inbuilt charger of mobile devices, especially if subject to heat, dust, vibration fluids (including humidity). Most comon in old mobile phones. 2) Electrical contact deterioration, as in the first point, but between battery, charger or the device, or combination of all of these. Repaired by cleaning stopping vibration. 3) Premature aging (battery and/ or charger). Statistical bad luck of factory production, especially after ageing, heat, moisture, vibration effects.

Seems like a lot of people more expert than me here. I just bought an expensive Li-ion powered car (no gas, only battery powered). The batteries were manufactured by a leading global manufacturer. The car was delivered to me with the batteries in sleep mode, in which state it had been for at least a week, probably two, possibly longer. I believe the batteries discharged to 2.6% of their recommended full charge, sleep mode kicking in at about 5-6% of full charge. I am being told orally by the car company that there has been no damage to the car’s battery (about half the value of the car), and that there is no chance of any copper shunts having developed, and that the car could have continued to sleep for another 4 months until any damage would occur. After owning and charging it for a month, I see what looks like 25% more daily idle battery discharge from my battery than others are experiencing. Should I believe them and not press any claim?

Dick I believe you introduced LiFePO4 into the discussion. There is obviously a difference between a battery that powers a handheld drill, small enough to have a steel spike driven through it with impunity, and a very large battery, powerful enough to start one of the largest turbofan jet engines currently in use.

Lead-acid automobile batteries are purpose designed to deliver very high currents briefly. They do not cycle very well. Most people are familiar with this type and mistakenly assume this type represents lead-acid technology. Lead-acid motive power batteries, in contrast, are purpose designed for cycling and, dollar for dollar, will outperform every other chemistry when used on deep discharge cycling duty.

James, I strongly doubt Boeing used LiFePO4 technology. it’s relatively new and the 787 was in design for many years. They are conservative about bringing in new technology especially where safety is concerned. even though LiFePO4 would have been a better choice, in retrospect. Go to http://www.batteryspace.com/lifepo4cellspacks.aspx and then click on Knowledge on LiFePO4 battery. Look at the Needle Test. this is where they pound a steel spike right through the battery, causing a dead short through all its layers. Also the short-circuit voltage vs. temp test. the battery gets hot but does not burn, outgas, or explode. This is a nasty test but LiFePO4 does it more safely than traditional Li-ion as the presentation makes clear. If you have evidence Boeing specified LiFePO4 for their batteries, please provide it here DL

Pier, the Battery Discharger you link to is mostly for testing batteries not for recommended maintenance or improving the battery. The benefits of discharging a battery depends on the battery type (chemistry). For lead-acid battery, deep discharge is BAD for the battery and will shorten its lifetime. For nickel-cadmium some people recommend occasional full-discharge and the re-charge, citing the memory effect of nickel-cadmium chemistry. I think your question may be about nickel-cadmium. Other people claim the memory effect is a myth. You will find good information on this battery-university site, it is a very good source of info on batteries of all kinds. Lithium-ion, like lead-acid, does not benefit from deep discharge. you will get longer life from lithium-ion chemistry by only discharging to 25-30% and re-charging to 80-90%. storing it at full charge (100%) for a long time is also not good. which is the topic of this forum, actually. There are some good articles and graphs here that explain it DL

Would this product be of any use? http://www.mightydeals.co.uk/deals/national/Gadgets-Gifts/Power-Bank-Recharger-/4033?lsid=550200030campaign=Affiliate_Windowutm_source=Affiliate_Windowutm_medium=Affiliate_Marketingutm_campaign=Affiliate_Window_Sale

I´ve been talked that to improve/increase the lifespan of out batteries, it is quite recommended to run discharging cycles every 6 months. Could anyone advice me about it? I was serching on Internet for a Battery Discharger and i found out the item below: http://www.amperis.com/en/products/misc/battery-dischargers/ I looking forward to hearing from your. Thank you very much for your collaboration.

Dick I believe Boeing would only have used the best of the best lithium ion technology Yet it failed. Lithium ion battery technology is inclined to burn. You seem to be digressing.

James: different technology. LiFePO4 is the variant that was the basis for the late great A123 Systems battery company, who were anxiously working to get into the electric car industry in a big way, before they went down and were acquired by a Chinese company (not sure it’s a done deal yet). BatterySpace.com sells LiFePO4 batteries by the way. Did you even look at the U.N. qualification test reports? It’s not marketing sales literature. Plain old Lithium-Ion is more prone to overheat and risk starting a fire, as the unhappy folks at Apple know. If you have information linking the 787 issues to LiFePO4 technology please let us know, with corroborating links supplied.

Dick L You are reciting the sales blurb. I took the lithium ion battery fire information from news reports. The airlines that bought the 787 don’t want to fly them until the problem is fixed.

Jason Lee, your iPad has its batteries wired in series. The voltage powering the device is the sum of the 3 batteries’ voltages, e.g. around 12V. They all discharge together. The MacBook probably has 2 parallel strings of 3 batteries but (like the iPad) they still all discharge together. James B take a look at lithium-iron-phosphate (LiFePO4) battery technology and the abuse these take in order to be certified safe (to meet UN safety requirements). I found a description of these tests on this site. They include pounding a steel spike through the battery. They still don’t overheat or start fires. Very tough technology and very long cycle life. I built a bicycle headlight / tail light system with them and they’re working great after 2 years DL

How about lithium ion battery safety? Hundreds, perhaps thousands of handheld and laptop devices have been burnt out by lithium ion battery fires.The Chevrolet Volt lithium ion battery caught fire several times. The Boeing 787 Dreamliner lithium ion battery caught fire several times. A submarine and several aircraft have been written off by lithium ion battery fires.

I think it’s rather impossible to do a partial discharge on Apple’s mobile devices. The iPad is equipped with three batteries, the MacBooks are equipped with six. But I’m not sure if they dishcarge one after the other or all together.

My Nikon digital SLR (D50) was bought in December 2005. I’ve taken about 7000 pictures, so I guess the camera isn’t used a great deal. It’s run by an EN-EL3a Li-Ion, 7.4v 1500 mAh battery pack. I recharge the battery (8.4v, 0.9amp Nikon charger) as soon as the camera displays a ‘low battery’ symbol in the viewfinder. I guess I recharge the battery 6 to 10 times a year. But I’m worried as I’m still using the original battery. I know I’ve only recharged it (maybe) 70 times. Well short of the 200 re-charge cycles. But the camera / battery never get cold or hot. As soon as the charge is complete, I put the battery back in the camera. At the rate I use the battery, will it last another 7 years? Or is there a finite time it will last? I have a digital volt meter. Is there a simple measurement I could make. that would give me an indication how much life there is in the battery pack? FYI: Immediately after charging the battery measured 8.31v One hour later is was 8.29v Eight hours later it was still 8.29v You expert thought would be appreciated! Best wishes from the UK!

tnx for useful artice. I have a new Lenovo Y580 and I don’t know how to charge it for the first time. would u help me plz.

My Lenovo G480 and other current Lenovo notebooks as I know has a software called energy management system which you can tweak to make the battery fully charge in case you’re always using unit without the AC power or it will have the charger charge the battery up to 60% level if you’re frequently using the AC power. Now I know the rationale of this 60% after reading this article. Thank you.

Thanks John H. I was just hoping that there was a trick to actually getting the performance from the batteries that was promised in the sales pitch for the product. Silly me!

Hi Carol I will get my 2 cents worth in and then hopefully some others will have something to add. From what you are describing, which includes both short run times and long charge times, I would have to conclude that your battery packs are reaching the end of their useful lives. The condition you describe sounds to me like the internal resistance of the batteries is rising. If you ascribe to the philosophies of B.U., then you understand that it is not possible to rejuvenate the lithium cells, and could also be dangerous to try. Unfortunately, the lesson you have learned is one I think most of us are perpetually repeating, and I am struggling to understand completely what the process is that destroys most of these cells. I have had very very few of these lithium cells which lived up to their stated life expectancies. My own experience would suggest 3 main factors: #1: Quality / proper use of charger circuit. #2.: Quality of actual Lithium cells. #3: Usage patterns and environmental (heat) considerations. The Комментарии и мнения владельцев listed above from Janet are along the same lines as what I believe; In effect, we are inadvertently killing a lot of these by putting them/ leaving them on chargers that are not well engineered.

How about the larger Li-ion batteries used in yard tools? Mine have decreased their life of charge time as well as the time it takes to charge them fully. These are green works batteries. Is there a way to turn this around and get the longer charge time back?

thanks to (almost) all who contribute here. I have really enjoyed reading the articles and the Комментарии и мнения владельцев/speculations. I have a few of my own, and I would love to hear back from all (almost) of you. First, from reading the Комментарии и мнения владельцев and seeing that there is not 100% agreement on the do’s and don’ts, it would seem to me there is a missing factor, which I would respectfully suggest is manufacturing quality of the battery. From my own experience, I have had some devices which were abused, yet maintained good runtime capacities for long lifespans, as well as others that were babied and died ridiculously premature and expensive deaths. In the case of laptop packs and other multiple cell assemblies like those used with cordless tools, my forensic investigations reveal individual cells which have failed either by shorting or some form of diminished capacity which renders the entire pack useless. My question today concerns the use of different charging connections and their effect on rates/quality of charge; as was mentioned by some, the charging circuitry is contained within the device (cell phone). As such, how is it that I get a faster charge from, say, the one that plugs into the cigarette lighter as compared to the one that is USB powered? Obviously the voltage sources are different, but does that mean the phone is so Smart it is deciding for me whether I want a quick charge or a very slow one? Shouldn’t the phone look at the incoming source and automatically regulate it down to the appropriate rate? All of the automotive and 120v receptacle charges I have charge at a rate that is much faster than USB. Is then the USB the preferred way? thanks

What about using a Touchstone dock (HP Touchpad) The general consensus on the touchpad forums is that it is safe to pop the touchpad on the wireless dock which also charges it to full capacity. Most people are leaving their touchpads on this dock every night and day and taking it off inbetween for minimal use. Ie checking email, browsing then throw it straight back on the touchstone. This would seem to indicate that these touchpads are permanently living at 100% or near caoacity at all of the time. Can this be safe or healthy for long term maintenence? Apparently their does seem to be a rash of issues re the HP touchpads battery not waking from powering off or discharging. Maybe keeping it topped off can save it from accidentally deep discharging, as it seems the auto power off chip may not be functioning correct with the software/hardware

It is best to use a charger designed for the intended product. If there is a reliable third party charger specificly intended to charge the battery for your product then it would also be acceptable. This is for safety reasons so that the monitoring and control circuits usually within the battery pack operate correctly to control the battery charge.

Janet wrote: USE THE MANUFACTURER’S CHARGER AND ALLOW THE CHARGE TO COMPLETE MOST OF THE TIME. To which I reply: But on what grounds do you assert that it has to be the manufacturer’s charger? Why wouldn’t a Targus Universal Charger (for example) have a control module capable of doing the control just as well?

The battery university is a tremendous service. Thanks for keeping it updated. I agree with Herve’s typo corrections above. I worked with batteries for many years, so I hope my words will take away some of the battery and charging anxiety that many have expressed in the Комментарии и мнения владельцев. Here are the key things to remember about Li-ion: 1. Li-ion has a long shelf life, except if it is stored fully discharged. Hence, the common recommendation to store at about 40% state of charge or above. STORE BETWEEN 100% AND 40% STATE OF CHARGE. 2. All name brand companies produce chargers that stop the LiIon charge at 100%. It is the best practice to allow the charger to complete the charge. Opportunistic charging (less than full charge) is ok and will not harm the battery. There are electronic control modules either in the battery pack or the charger that decide when the charge is complete. USE THE MANUFACTURER’S CHARGER AND ALLOW THE CHARGE TO COMPLETE MOST OF THE TIME. 3. You do not need to store the battery in the refrigerator and it may be harmful to store the battery in the freezer. Your battery is happy at the same temperature you are comfortable. The most important thing you can do for the battery is do not leave it in the car on a hot day. Same goes for your dog or your kids. STORE THE BATTERY AT ROOM TEMPERATURE. 4. If you are usually plugged in when you work, the battery does not even need to be in your laptop. (Check your instruction book or if you have children, use good judgment.) Just make sure the battery terminals are taped so you do not inadvertently short it. OR Try not plugging in the laptop some work sessions. Most will tell you when the battery is getting low and you have plenty of time to plug it in (but this is using up your battery life). Either way avoids keeping the battery at full state of charge all the time and repetitive charging (starting charge on a fully chargd battery) which is detrimental to battery life. There is a variety of charger quality on the market. Some battery/charger combinations will detect this situation sooner than others. TRY NOT TO KEEP YOUR BATTERY ON CHARGE OR FULLY CHARGED ALL THE TIME. I understand the batteries are expensive and you want the most life out of them. To get the most life from the battery really is as simple as the 4 BEST PRACTICES listed above. Your life is too short to be babysitting your batteries trying to decide the depth of discharge for today and/or running to the fridge for a battery. Enjoy.

I read the original version of this article (whose only table was the very enlightening Table 3) many years ago, thanks to the authors for updating it with more tables and very informative data. I’m afraid there are two typos left:. in the comment on Figure 1: A pool of new 1500mA Li-ionbatteries.- should be A pool of new 1500mAh Li-ion batteries. in the comment on Table 4: Every 0.01V drop.- should be Every 0.1V drop to match the table values (e.g. 4.2 to 4.1).

I’ve written a small program to perform unattended shutdowns of battery powered devices (such as laptops) at specific charges. It is for Ubuntu or Linux users, however if there is enough interest I’ll consider porting it for Windows and mac: https://github.com/jfeltz/powersleep

Hi. This is Hassan. i have HP probook 4530. The battery is PR06 Notebook Battery 3ICR19/66-2. 10.8Vdc 4200mAh. I face power outages almost after every one or two hours. If i charge my battery to 40% and then put in fridge and during power outage i will use the battery. Is this practice a good one? If yes plz tell me the %charging that i should use for the battery.

Just search for it in Google by putting in the model name with the words replacement battery in the search box. Note that laptop batteries are not that cheap you should expect to pay at least 50.

I think my battery for the laptop is now almost at the end of its useful life ! I can only get just over an hour from it when fully charged. Is there anywhere that is recommended to buy a replacement one. I did ask the laptop manufacturer (Acer) but it was horrendously expensive. Thanks in anticipation

To reply to Big Mart I think the best thing to do is to charge to something like 97% to 98% and that will restrict the battery wear to the absolute minimum and won’t have to compromise too much batter capacity. Having said that I think it is inevitable that you will need to fully discharge the battery from time to time when on the train for example but you just bear in mid that this will most likely damage you battery a bit unfortunately. Hope this helps. Regards

Andre If you never charge it to 100%, what about when you want to use just battery power? I will be going on a train journey tomorrow, and want to use it on the way. There are rarely mains sockets. I want the maximum amount of time available.

this is for laptops i presume i dont think this works for phones like the htc one x or has that been tested to?

Hi I’ve been monitoring my battery wear for a while now carefully with BatteryBar Pro v3.5.4 and my conclusion is that over-discharging and over-charging your battery is damaging and always results in wear. So now I never allow the battery to trickle charge to 100% pulling out the plug before around 90% to 95% max. I then run the battery until around 50% to 35% and then start charging it again. By doing this all the time, BatteryBar Pro registers the minimum amount of wear. In fact a slip from this regime always seems to result in a few percentage points of wear. I think I basically do manually what some systems can do automatically through a setting in the BIOS (wish I knew about this feature before buying my laptop!). So that’s my comment really. I really recommend BatterBar Pro so you can really keep an eye on what is going on. But remember the computer needs a restart for any wear level numbers to be updated. Hope his helps! Andre

This ‘tree-power’ article is pretty interesting. For those of you who may be well-versed in. charge an ‘e-vehicle’s’ battery pack? ‘Electrical circuit runs. 39;s enough power in trees for University of Washington researchers to.

These days, we have a lot of Smart Phones on the market like the iPhone which we cannot remove the battery for charging using other machine. Is there a way, we could analyze or using other accessories to charge it white the battery still inside the phone.

I had a question. I have a 2.3 Android with the BL-4D 3.7 volt Li-on battery. I have found that overcharging does reduce battery life. I have had the phone only a couple of months and I do not use it a lot because each time I do after a couple of hours the battery is low. I received two batteries with the phone but it is still a problem. I have let it get to 0 percent a couple of times and recharged it to 100 percent. This has not helped. I know not Smart but it was a suggestion I read before I read the article. I have not had problems with previous phones when it comes to battery life. Am I doing something wrong? I e-mailed the company but they have not responsed. Any help would be greatly appreciated. Also what Android phone has the best battery life? Is there an extended version of the battery I have?

Looks like a few Комментарии и мнения владельцев were deleted, including my reply to Matt and that without an explanation. nice. Matt: Here’s the gist of my last reply. You were right about one thing: you should have “let my little statement die” instead of responding with your angry screed. Yeah, try to sweep the fact under the rug that I cleared up your whole misconception about deep discharges and the erroneous advice you gave with it. That was also the sole purpose of my comment, so I guess I was right about two statements. Not a bad quota in a two statement post. I never said anything about throwing a battery out after it is “deep discharged”. Nor if discharged to 11%. Never said you did. Neither does the article. The article used 70% capacity as a threshold and called it end of life. I’d pretty much call a battery that has reached its end dead. What do you do with dead batteries? I throw them out. Nor about throwing it out after three weeks of standby. That is your fantasy. No, that was an analogy to show you how useless numbers based on such high thresholds are. By definition of the article, you’d have to get rid of batteries at that point because they are considered dead. The conclusion you should reach, other than being sidetracked by your own poor way of arguing, is that a more realistic threshold might show that the charge that could be expected would be pretty much even for certain charge levels. May be the opposite would be the case, but no one knows that. That’s why you can’t use the numbers as a basis of your argument. Their nature just doesn’t allow any conclusions. But the difference between 11% and 10% is obviously small. 10% DISCHARGE of Table 2 != 11% CHARGE (=89% discharge). Yeah, the difference between 10 and 89% (or 90 and 11% if you want to look at the charge levels) is obviously small. And how did you miss the title of the article? Despite your pretense, it is NOT specifically about 4.2V batteries, it is about Li-ion in general. And where does the article say that the protection circuit is the same for cell phone and notebook batteries? You imply they work exactly the same, even though that makes no sense at all since both battery types are designed for totally different usage scenarios. Your angry screed, full of equivocation, shows only your own inability to understand either me or the article. Your obvious lack of understanding and your poor way of arguing make me rather smile than angry. How you get anger out of my reply is beyond me, but you’ve been misinterpreting the article and my replies so much that I’m not really surprised. Btw, provide proof for your so called equivocations. My replies are right there. Use quotes for once in your life. If anyone ever gets anything useful out of it—which is doubtful—it will be the article’s author realizing what he could have worded differently to better avoid confusion and needless arguments. The article is very clear in what it says. It just doesn’t take amateurs like you into account who can’t even distinguish percentages of charge and discharge levels. But even if he had worded it perfectly, there is nothing he can do for anyone clueless enough to believe as you do, that “Companies have the legal obligation to deliver products who function within the expectations of their end users”. That was funny. Just because you found it funny doesn’t make it untrue. What I described is part of many case law and codified law based countries. You clearly are no lawyer and you also clearly lack proper common knowledge: If a defective product causes an accident that results in death, injury or property damage, the manufacturer, distributor, retailer and lessor of the product may be liable for the damages caused by the product. [. ] The plaintiff must establish that a product has a defect that made it unreasonably dangerous at the time the product left the control of the defendant. [. ] It may also be possible to show that the product was defective because it did not perform in keeping with the user’s reasonable expectations. Source: http://www.osbar.org/public/legalinfo/1047_DefectiveProducts.htm Why did you THINK most software license agreements disavow any “fitness of purpose”? Software != Hardware. Software doesn’t explode or catch fire when being deep discharged. Also, show me such an agreement for any non-Software product. You won’t find any, but just in case you do, it would be in violation of basically any western law.

I must admit to being slightly confused. You say the worst condition is keeping a fully charged battery at elevated temperatures, which is the case when running a laptop on the power grid but then go to say The question is often asked: Should I disconnect my laptop from the power grid when not in use? Under normal circumstances this should not be necessary because once the lithium-ion battery is full, a correctly functioning charger will discontinue the charge and will only engage when the battery voltage drops to a low level. Most users do not remove the AC power, and I like to believe that this practice is safe. Surely leaving the laptop plugged in all the time will lead to keeping a fully charged battery at elevated temperatures, no?

@Matt Refering to Table 2 Assuming a 10% DoD gives you 1 unit of use and you can recharge it 4700 times you’ve gotten 4700 units of use out of the battery. Now if you have a 25% DoD you get 2.5 units of use per recharge. You can recharge it 2500 times you’ve now gotten 6250 units of use from the battery. If you have a 50% DoD you now get 5 units of use per recharge. You can recharge it 1500 times you’ve now gotten 7500 units of use from the battery. If you have a 100% DoD you’ve now gotten 10 units of use per recharge. You can recharge it 500 times you’ve now gotten 5000 units of use from the battery. In addition keeping the battery topped off is contradictory to the information contained in Table 3. I’ve found I obtain the best life and length of use between charges by allowing the battery to dischage till the device tells me it needs to be recharged, and then recharging it at that time.

No, Xiaoping, you are the one guilty of the lion’s share of the charges you fling at me. You were right about one thing: you should have let my little statement die instead of responding with your angry screed. I never said anything about throwing a battery out after it is deep discharged. Nor if discharged to 11%. Neither does the article. Nor about throwing it out after three weeks of standby. That is your fantasy. But the difference between 11% and 10% is obviously small. And how did you miss the title of the article? Despite your pretense, it is NOT specifically about 4.2V batteries, it is about Li-ion in general. Your angry screed, full of equivocation, shows only your own inability to understand either me or the article. If anyone ever gets anything useful out of it.- which is doubtful.- it will be the article’s author realizing what he could have worded differently to better avoid confusion and needless arguments. But even if he had worded it perfectly, there is nothing he can do for anyone clueless enough to believe as you do, that Companies have the legal obligation to deliver products who function within the expectations of their end users. That was funny. Why did you THINK most software license agreements disavow any fitness of purpose? They would not be able to do this if your ‘legal obligation’ were real. Newsflash: it is not.

No Matt, you just can’t read and throw any term into the ring that makes sense to you, regardless of its meaning. Your words: No, he should NOT wait until the battery is discharged to 11% That would be one of the deep discharges that shortens battery life. My reply was about explaining how 11% is NOT a deep discharge, because there is a clear definition of what a deep discharge is and which you apparently don’t know. I also never claimed that discharging the battery by 100% would not limit its recharge cycles. I didn’t even go near that. You, Matt, need to learn to comprehend instead of just looking at a few isolated numbers in the desperate attempt to find proof for the twisted ideas you apparently try to convey. You’re welcome to disprove what I actually said by using my own words, instead of just claiming that you got it right, while you clearly have no clue what you’re talking about. Just to not just let your little statement die like it probably should, I’ll put table 2 into perspective. Something you should have done yourself instead of treating as the absolute truth. First of all, table 2 is based on 4.2V cell phone batteries, while I was talking about notebook batteries. Both types are designed for totally different uses. While a cell phone battery is the sole source of energy for a cell phone’s life and is being recharged on a regular basis, a notebook battery is only there to deliver occasional power to a much greater extent. Charging also only takes place occasionally (granted the user/software/charging electronics) behave properly. Secondly, the number of charges is determined by using an arbitrary value of battery life. The text even says so itself. Did you even read it or did you just look at the pretty graphs and numbers? The threshold value could be anything and the resulting measurements are of little use for other batteries. Proof lies in the numbers itself: 100% 500 cycles = 50.000% total charge 10% 4700 cycles = 47.000% total charge Discharging a battery by 100% nets more charge over the battery’s life than only using it up by 10%. So, even if the words you laid in my mouth were actually uttered by me, I’d still be right due to the fact that you didn’t analyze what you argued with. Even better: The arbitrary threshold of 70% is unrealistic. Who gets rid of a battery just because the cell phone only offers 3 weeks of standby instead of 4? Who buys a horrendously expensive notebook battery just because the battery only delivers 5 hours of work time instead of 7? A threshold of 30% would be much more realistic and would probably show that the 100% discharge nets much more charge than the 10% one. The gap between 50% and 25% discharge would probably also get a lot smaller, or may be even vanish at all. I don’t know and you don’t either, but the 10%. 100% discrepancy shows that this table is of little worth for your argument. Repeat the test with a wide array of current notebook batteries of different brands with at least 10 per brand to minimize statistical flukes and then you have some numbers to argue with. Right now you have squat, let alone logic or analytical skills.

I just cannot believe how many people comment here without having a clue what they are talking about. You, Xiaopang, are one of these. DId you even LOOK at Table 2? How did you miss the huge difference in number of cycles for a battery discharged to 10%? You are the one who completely missed what the article says, I got it right.

Matt J., you’re quite exaggerating by claiming that discharging down to 11% is already a deep discharge. Think logically for a moment: Companies have the legal obligation to deliver products who function within the expectations of their end users. If a product would actually be damaged extraordinarily (in this case a deep discharge would qualify for that) while its use is also within what could be expected from a normal user, then this might make the company vulnerable to law suits. Not just because they’d sell a falsely advertised product, but also because it would be dangerous. A deep discharge should be avoided not just because it might ruin the battery, but also because such a battery might suddenly start to burn or even explode. Windows allows to go way below 11% (Xp 3%, Vista/7 5%), so as a result millions batteries would be damaged and a plethora might catch fire and burn. but that doesn’t happen. and for a reason: A deep discharge per definition is when the cell voltage drops below a specified value. For 4.2V cell phone batteries this value is usually around 2.5V (60%). For notebook batteries that usually operate in the range of 10-12V I couldn’t find any values, but applying the same ratio as above, 60% would equal 6-7.2V. To actually debunk your carelessly spit out claim I actually let my Notebook discharge the battery down to 30mW (0%) while I measured the battery voltage. The battery usually operated at 11.5V when the computer is connected with the charger. On battery the voltage is around 11V and goes down the more the battery is discharged. At 30mW charge the battery still had a cell voltage of 9.6V and thus was way above what would qualify for a deep discharge. A deep discharge usually only occurs if a battery is used by devices that don’t turn off automatically on low charge and draw so little charge themselves that batteries can be discharged much longer and deeper than through normal devices. Notebooks not just turn off automatically, they also need a pretty high charge level to even power up, so using up the battery entirely still leaves enough charge for the battery to not be damaged (anything else would be a pretty big oversight/design flaw, wouldn’t it). Li-ion batteries are equipped with small chipsets though that control the charging process and report stats back to the operating system. This also draws power, so discharging a battery down to 0% and storing it like that for weeks would eventually result in a deep discharge. So, for all of those who are in doubt: try it out yourself if you are unsure. You can measure the battery voltage with hardware monitor.

This information has allowed me to fully recover the use of Lithium-ion cordless drill batteries for I had thought were irreversibly damaged. It’s good to understand a little bit of the science and practices of batteries and long-term storage. I’m taking far better care of my tool batteries now, and I’m running on a set of two I hadn’t previously cared for properly. Life extended by two years so far! Thanks for this information.

Hi Thanks for a great article! But I wonder if the conclusion drawn on table 2 are absolutely accurate? Here I have extended it with a third column, taking the deterioration into account. DoD Cycles Total Usabilty 100% 500 435 50% 1500 638 25% 2500 531 10% 4700 400 The added last column says how many times of full charge you will get out of the battery in total during its life time with each approach. Assuming a linear deterioration of the battery from 100% to 70% of its original capacity (This assumption is backed by a graph in the article) So the integration is simple, and can be replaced by a mean factor of 85% [] to the pure product. This would yield that the optimal total capacity gained from the battery over its lifetime is a DOD of around 50% (Plotting the four points and combining with a smooth curve indicates that the maximum is around 60-50% DoD) [] precisely Sumn=0 to N-1 of DoD(1-30%n/N) =DoD(N. 30%Sumn=0 to N-1 of n/N) =DoD(N. 30%(N-1)/2) =DoD(N85%-15%) ~DoD N85% Best Regards Eske Rahn

@ Big Mart ~ Ask Matt J. ~ he seems to be an authority on this subject. ! @ Matt.J. ~ You’ve got me wrong again. No where in the article it says that 11% is deep enough to have a significant effect on battery life This is purely based on your assumption. Throughout my Комментарии и мнения владельцев I have bee n mentioning COMPANY and you said no matter what HP chargers say. For your kind information, no charger manufacturing company in the world specifies, the level at which a battery should be recharged ( 11% / 14% ) that is purely the responsibility of the Laptop manufacturing company. Chargers just indicate, basic specifications. its the laptop manufacturing company which tells you when to recharge.If you own an Android mobile phone. you should be familiar with Lithium batteries. Just go to Google search and you will see hordes of articles and blogs on Lithium batteries ~ on how to maintain them, charging etc.WHATEVER INFORMATION I AM POSTING HERE IS NOT HEARSAY ~ THEY ARE BASED ON MY PERSONAL EXPERIENCE AND CONFIRMED BY H P.

Well I am now even more confused. Is there anybody that works in the battery industry that can give a definitive response?

@Rajdeep Completely hypothetical speculation is no substitute for reading and understanding the article. Especially not when that speculation relies on unlimited benevolence of a company. Discharging to 11% IS deep enough to have a significant effect on battery life, no matter what HP chargers say. That is clear from the article.

@Matt.J ~ If my suggestion is in contradiction to this article, why does even a company like HP has pop ups coming at 14% and then again at 11% by DEFAULT. The company insists that BEFORE YOU CHARGE YOUR BATTERY, YOU SHOULD DISCHARGE IT ~ KEEPING IN VIEW A FULL DISCHARGE CYCLE. Every one knows that if you go beyond 11%, the Laptop will hibernate, so the cut off point is 11% WHICH IS NOT A DEEP DISCHARGE. Had this been so, the companys would insist you charge your battery earlier, say at 20% or 25%, and the Pop ups would appear then. This has been agreed upon by HP too. I don’t know which Laptop you have but I suggest you illicit their opinion too on the matter.And if you not agreeable to my suggestion, its better you don’t follow it. THERE IS NO COMPULSION !!

@Rajdeep- Don’t feel too happy, your claims are quite contradictory to the basic claims of this article. No, he should NOT wait until the battery is discharged to 11% That would be one of the deep discharges that shortens battery life.

Run down from 60%. to 11%. Put off your computer and charge as usual to 100%. i agree, its better to be sure.

Cheers for that. If I have finished what I am doing and it has got to say 60%, do let it continue up to 100% and then run down, or just run down from that 60%? Just want to be absolutely clear on what I am doing !

For Tina ~ The objective of blogs and articles is to ensure people exchange ideas and learn. At one time, I too, was ignorant. today I feel happy that i am in a position to reassure people. Maybe one day people will ask you about Laptops and you will be able to answer their queries

For Bill Mart ~ suppose you are on battery, wait till the second pop up arrives ( 11% ) and then start charging you battery ( plug in mode ) if you have important work to do, carry on. There’s no harm. Preferably put the laptop off cos a lot of heat is being generated ( while charging the battery gets hot otherwise too and secondly the Laptop generates enough heat when on ). Remember the biggest enemy of your battery is heat. Apart from this there’s no difference if you charge your battery with the Laptop on. All the Best.

Thank you Rajdeep. However, if I am running the laptop using battery power it will probably run out of power while I am still using it (should I let it drain completely, or start recharging it at, say 10%?), so therefore I would have to recharge it with the laptop on. Does that make much difference?

@Rajdeep Sing. YOU ROCK. I am all set to go. See I have my Master’s Degree in Reading unfortunately not all types of reading. lol. Thank you very much for not letting me feel stupid or embarassed!

For Tina ~ Complete discharge is known as deep discharge. which means your computer hibernates. No this is not good especaially for the hard disk as a reverse voltage can cause serious damage. When the voltage drops to say 14% a pop up tells you to plug in before your Laptop hibernate. Rightly so. So just charge your battery Preferably with your Laptop off till it attains 100%. A second Pop Up ( I too have a HP Pavilion g4 ) appears later when you are on 11%.PLEASE DONOT TAKE A RISK AND START CHARGING. Somebody suggested 10% to indicate a deeper discharge in an effort to calibrate the battery but that is different subject altogether which your new battery will not require now. And Tina please remember that all HP laptops reveal the correct battery reading as long as you have the applicable charger and battery ( which comes from HP )and you have not messed around trying to calibrate your battery.In the beginning every one is scared ~ but later it will be your Laptop which will teach you a lot of things so dont have to feel embarrassed.

if you are mostly on the PC it is better that you take out the battery and store at 40% to 45 % and store it till you work on your Laptop over weekends Once charged to 100%, power your laptop from the battery till it drains and again charge to 100 % preferably with your Laptop off. This will ensure that your battery is always in working condition Nothing to do when your battery is fully charged. Just remember never to store batteries at 100%, no matter what. Use your Laptop and bring it down to atleast 45% before storing. Remember your charger is only working when you are on plugged in mode. In battery mode your charger is off so nothing to worry !! please make sure before inserting your battery that the contact points are clean. Gently rub an eraser over the contacts and blow off the remnants from the points. If you follow thee points, i am sure your battery will give you good service. All the best !!

@Big Mart. thanks for agreeing with me. @Rajdeep and @Matt J. I am a bit conflicted now with what you are both saying. Do I allow it to completely discharge then? I thought completely discharging a Lithium-ion battery was NOT a good idea. Sorry again for my confused state of mind. lol!

@MattJ Thank you for your advice. What should I do then with my Acer Aspire 5715Z. The only charger I have for it is the charger within the laptop. Should I put the battery back in and then use the laptop off the mains? Do I do anything more when it reaches 100% charged? I use my PC most of the time, and tend to only use the laptop when I away from home, ever 2. 3 weeks for a weekend.

For Tina ~ Once in a while, in plugged in mode with the battery in your Laptop go to all programmes H.P.Support Assistant Trouble Shooting Power and Thermal Battery check. ( click on Battery check and wait ) Your Laptop will tell you the state of your battery. So far your battery is new, you should not a have a problem. If you get a message saying CALIBRATE YOUR BATTERY, please feel free to contact me at rajdeep218@gmail.com

For Tina ~ Follow this. Allow the battery to charge fully ( with your Laptop off ) Once charged use your laptop on battery mode till it discharges and you get a pop up suggesting that you have to charge your battery. Again charge your battery ( with your computer off ) and use your battery as above. only once in a while you may use your Laptop plugged in with the battery fully ( A circuit in the battery stops the battery being charged once it attains 100% so as to protect the battery from being over charged ) If you a using your Laptop more as a desktop for more than two weeks, it is better to take out the battery and keep it in a coll dry place. But please use your battery atleast once in a month. Please store your Laptop battery at 40% ~ 45 % charge level ` at which oxidation takes place the least.

For Tina ~ All new batteries come in a semi discharged state. You should have charged it fully and even after that for atleast two hours before using your computer. Never mine. Now charge the battery fully before using it. Let me know !!

@Big Mart. Close, but not quite. What I said is that you should leave the laptop plugged in with the battery as often as possible IF the charging circuity is high enough quality. Unfortunately, neither this article nor the vendor specs tell us enough about the chargers: but overcharging is also bad for batteries, and poor chargers WILL overcharge the battery. I am not sure which of my computers and chargers have high enough quality. I feel pretty confident of the Apple computers, less so of Radio Shack or Targus chargers bought for IBM compatibles.

I have to agree with Tina. I found the responses very confusing. So, Matt J, are you saying you should leave the laptop plugged in with the battery as often as possible? What I have gained from the article and responses, is I have left the battery drop to approx 50%. I have removed the battery and running the laptop (where practicable) off the mains. Is this right? If not, please explain so myself and Tina can understand it. Thank you.

@Tina The article was not THAT hard to read;) But the answers to your questions are all based on the following principle expressed in the article: shallow charge/discharge cycles are better for battery life than deep ones. So No, you do not allow it to completely discharge. 10% discharges allow the battery to last for much longer, but are themselves too small to really be practical. If your laptop and charger have good control over the charging current, (a question this article does not even try to answer), then you should just leave it plugged as often as possible.

I am sorry about my lack of understanding but I just purchased a new battery for my laptop. I have an HP Pavillion. It came with 74% charge so I continued to charge it to 100%. Now I want to make sure that my new battery lasts longer than my old battery. I tried reading and understanding the article but my brain cannot seem to process it. Do I allow the battery to completely discharge and recharge? If so, how often? If not, how far down, percentage wise, do I allow the battery to discharge before I allow it to recharge. Again, my apologies for my lack of understanding. Thanks!

Charging a battery in just seconds is NEVER a good idea, ‘batman forever’. Remember what the article above says about heat shortening the life of the battery: charging too fast WILL raise the temperature too high and shorten its life.

EBL INR 26650 Li-ion Rechargeable Batteries 3.7V 5000mAh


Each order from EBL is shipped from the United States and will be delivered by standard shipping with an estimated delivery time of 7-14 business days.

When will my order be shipped?

We usually take 2 to 5 business days to schedule shipments, except for pre-sales items. A notification will be sent to the customer via email after shipment.

Which countries do you ship to?

We can ship to the United States, Canada and Mexico.

Do you ship internationally on your website? Can you ship to my country?

Our website is still testing shipping products worldwide. Therefore, the shipping cost charged at checkout is an estimate and will be based on the actual postage cost incurred when the product is sent by courier (generally based on the weight and volume of the products).Please Note: We will refund the excess if the postage charged is more than the actual shipping charge. Meanwhile, if the postage charged is less than the actual shipping cost, we will also charge the customer for the additional shipping cost.

Domestic Shipping

Orders over 25

Orders under 25

Standard shipping charge of 5

Weight Between 1-4oz

Weight Between 5-15oz

Weight Between 16-25oz

Weight Between 26-49oz

Weight Between 50-80oz

Delivery areas within the U.S.

EBL official website supports delivery to most areas of the United States. We cannot deliver to the following areas:

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Please note: Power stations and solar panels cannot be shipped to Hawaii, Puerto Rico or Alaska.

Thank you for your understanding.

bu-808, prolong, lithium-based, batteries, 18650

International Shipping

We also offer international shipping to the following countries: Canada and Mexico.

And we can ship to other countries, but only for wholesale orders. Please contact us at support@eblofficial.com for more details.

As we are still testing shipping of EBL products to all parts of the world. Therefore, the shipping charges charged at checkout are an estimate and the actual shipping charges will be based on the actual postage costs incurred when the product is sent by the courier (generally based on the weight and volume of the product).

Please note

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Delivered but Not Received

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Welcome to EBL’s Warranty and Refund Policy page, where you can email us directly if you encounter any quality-related problems after purchasing EBL products. We apologize in advance for any inconvenience your purchase of EBL products may cause.

If your product is defective during the warranty period, please contact us by mail or via live chat and let us know what we can do to help you.

We will take care of all quality-related issues and offer a REPLACEMENT or FULL REFUND, including the return shipping costs.

Please note that this page is for products purchased through eblofficial.com. For products purchased through the EBL store on sites such as eBay and Amazon or from EBL’s authorized distributors, please contact them directly.

Warranty Period

All products purchased from EBL are guaranteed with a 12-month hassle-free warranty. In each case, the warranty period is measured starting on the date of purchase by the original consumer purchaser.

Valid Proof of Purchase

A sales receipt from the consumer’s first purchase, or other reasonable proof, is required in order to confirm the start date of the warranty period. Please provide both of the following vouchers when processing warranty claims:

  • Provided order number from eblofficial.com.
  • The email or phone number or name used to place the order.

Limited to Original Consumer Buyer

The warranty on EBL’s product is limited to the original consumer purchaser and is not transferable to any subsequent owner.

Warranty excludes :

  • Products without sufficient proof of purchase.
  • Damage caused by misuse the faulty parts.(including static discharge).
  • Improper installation.
  • Damaged by yourself.
  • Purchase the product by mistake.
  • Neglect, accident or modification, which have been soldered or altered during assembly.
  • Complimentary products.

How to claim warranty?

To obtain warranty service, please contact our customer service team at support@eblofficial.com.


EBL will replace any EBL product that fails to operate within the applicable warranty period due to defect in workmanship or material. The replacement product assumes the remaining warranty period of the original product.


We offer a 30 day hassle-free money back guarantee on items purchased directly from eblofficial.com. ( We only provide prepaid return label for quality problem products. Other than that, customers need to pay for the return shipping fee. ) If for any reason you are not satisfied and would like to return an item, please let us know within 30 days.

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There are certain situations where only partial refunds are granted:

  • Products with missing parts that do not affect normal use.
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Return shipping costs should be paid by the customer in the following situations:

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Late or Missing Refunds

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How do I return an item?

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⚡ 26650 Rechargeable Battery ⚡

【26650 Battery Specifications】

Store humidity

≤70mQ2(AC Impedance, 1000 Hz)

26650 cell dimensions/26650 battery diameter

【 Ultra Long Lasting 】

EBL high-performance Li-ion 26650 batteries have been manufactured with premium raw materials and high-density cell technology, they will give your devices enough power and last longer, so you can rest assured to use your various devices.

【 High Quality Competitive price 】

100% Brand New and High quality. 3.7v 26650 With a high capacity of 5000mAh, it can last a long time. Superior performance under low-temperature conditions. EBL 26650 li-ion rechargeable batteries for high power LED flashlights, electronic devices and other equipment 26650 size(please carefully confirm whether your equipment needs 26650 size before your order)

【 Safety】

Quality Steel Shell, very sturdy and durable. Effectively prevent the 26650 rechargeable battery from leakage and short circuit.

【S torage 】

The rechargeale 26650 cells stored in the RT (room temperature), the 26650 battery’s cell should be charge once per 6 months to avoid the cell over-discharge. The customer should charge the cell for I hour by 0.5C for long-term storage.

The 26650 li-ion battery working principle is to release energy by electrochemistry to provide the power; actually, it is a chemistry product so that it should be re-charged to active the battery energy after a storage period because its performance will be attenuated after long term storage. If you cant to knwo more information about battery storage, related battery storage article here: Battery Storage Guidelines!

【 What You Get 】

2/4/8/16 Pack lithium rechargeable 26650 batteries 3.7V 5000mAh

All ebl 26650 batteries are protected by plastic battery case. Reliable Li-ion packing.(Provided with every pair of 26650 rechargeable batteries purchased )

We also sell 26650 rechargeable batteries with charger/ 26650 battery charger As reputable battery wholesaler, you can bulk buy batteries in our Eblofficial store at very affordable price, but high quality household batteries and rechargeable battery chargers.

Further helpful information about 26650 batteries:

【What is the size of 26650 battery?】

A 26650 battery is a type of cylindrical rechargeable lithium-ion battery, 26650 battery size: 26mm 65mm(DL). It is one of the larger rechargeable battery sizes and is commonly used in high-drain devices such as flashlights, power tools, and electric bicycles. The 26650 battery has a high capacity and can provide a substantial amount of power, making it a popular choice for high-powered devices that require long-lasting energy.

【Are 18650 and 26650 interchangeable?】

No, 18650 and 26650 batteries are not interchangeable because they have different battery sizes. Since the 26650 battery size.26mm 65mm(DL) has a substantially bigger diameter than the 18650 battery size.18mm 65mm(DL), it cannot be used in accessories made for that smaller battery.

How to Know a Fake 18650 Battery

About: Tech nerd like web technologies and gadgets. Kitesurf on weekends and recently got involved in 3D printing technology. About danleow »

An average genuine 18650 batteries will weigh about 45g and no nothing less than 42g. You can see I have a fake 18650 battery in the pic weigh 32g only and the genuine 18650 battery weight 45g. Some genuine 18650 battery can weigh more than 50g. Good brands will tell you the weight of the battery.

You can use a digital kitchen scale.

Why fake 18650 battery weigh less? That is because inside is a smaller battery with step up circuit which wrap in layers of paper and stuffed inside a 18650 battery size case then heat shrink in a tight plastic label sheet to make it look real.

Genuine sellers will specify battery weight in their product description/sheet.

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Комментарии и мнения владельцев

There is a lot of great info here both in the video and in Комментарии и мнения владельцев too. I am learning from everyone I can about using these 18650 batteries but I dont see much info about their C ratings only mAh’s/fake or not. I use them for very high discharge applications (custom r/c vehicles) and now using an awesome little spotwelder to help create them. No more trying to solder/fail batteries. If i can figure out how to create (instructables) i will. https://youtu.be/TJq31wVMOuw

Fake is the wrong word. A fake battery would be one that is not a battery at all. In fact, there are empty cells made that are not fake, they are simply sold as empty to fill a mechanical void for battery packs with odd numbers of cells, and are used to fill a space mechanically for the structure of tha pack, without unbalancing the individual strings of cells. This is common in higher density packs that have staggered string sizes, or a pack with a specific shape, but wanting to maintain the fullness of the pack within that shape.

There are a lot of different capacity cells sold, and each weigh a different amount. There are a lot of reasons for using smaller cell sizes, ranging from reducing the cost of the cell for marketing or cost reasons, to safety regulations for a particular regulated application. There are safety standards for appliances used in critical or hazardous environments that might limit how much lithium is present, or have containment requirements that reduce how much you can put in a cell and still meet the safety spec. A cell that is integrated as a backup of short duration might be made for one application, and find it’s way to the surplus market where it is sold on ebay. Nothing fake going on there, as long as no lies are being told.

If the battery has a rating that matches it’s actual capacity, any capacity or weight is valid. That is a big IF as exaggerations and rip-offs are common. Anyone can cut the shrink wrap off a cell, and replace it with a new wrap, with whatever markings they want. These repackaged cells can simply be remarketed cells, or actual forgeries of popular brands. Some flashlight makers rebrand all batteries they sell. Some are honest and some are not.

And besides capacity specifications, there are safety features, and the absence or presence of cell protection circuitry that has an impact as well.

When evaluating a cell from a new vendor, you should perform a capacity test where you drain a cell to the rated cutoff voltage, then test the charge cycle to see how much charge it takes, then perform a discharge at both slow and fast rates to see the results from thos tests. Discharge rates matter! The slower you discharge a storage cell, the more power in total you get from it. And that affects the cell rating for a given application. So the same cell can have a different capacity depending on what it is used for.

And a sand filled cell sounds fishy, and probably is. Unless there are weight requirements that need to be met coupled with a lower capacity requirement. The buyer of a manufacturer’s production run is responsible for the specifications of that run, and their reasons and final product markings could be honest or dishonest. While I would agree in principle that dishonestly market batteries are somewhat fake in nature, the word fake is not an accurate word in most cases. A buyer will always do capacity spot checks as part of the qa of the incoming parts, as most parts have a certain percentage of bad units, and for a product build there will need to be some way to accommodate for the occasional bad part, especially from a new manufacturer or from a surplus supplier. Even new chips might be remanufactured pulls from scrap electronics, so the incoming QA team is there to keep suppliers honest.

So you are right that there is more to a battery than the claims printed on the shrink wrap cover. But the QA process is so much more than just weighing the cell.

The Best Flashlights of 2023

Modern flashlights are applicable for a wide range of scenarios, offering longer battery life, powerful LED luminance, and excellent color rendering. Check out our picks for the best flashlights of 2023.

If you want a powerful, versatile lighting solution, the best flashlights still offer advantages over headlamps in many scenarios.

Flashlights point wherever you want, not just where your head is pointing. Also, due to fewer weight constraints, they tend to have more powerful, longer-lasting batteries and incredible power for modest-sized devices.

And to be honest, I’m a flashlight buff. Yes, I also use headlamps a lot when I’m outdoors. But more often than not, I grab a small flashlight from my truck center console and, if I need two hands for a project, clasp it in my teeth. I just love having the ability to point it wherever I want without having to crane my neck in a specific direction.

So if you love torches, read on for what we’ve determined to be the best flashlights available today. Because GearJunkie focuses on the outdoors, I rated these based on weight, size, battery life, color rendering, and lighting versatility. You can learn a lot more about how I tested and chose these flashlights below, but right up top, I’d like to call out that this article focuses on truly excellent flashlights that can perform day in and day out, whether you use a light professionally or simply need one for camping or to store at home for a power outage.

Note: This isn’t a list of “light cannons,” as you’ll rarely need 1 million candlepower. But I did include one monster in case super-powered lighting is your jam!

Be sure to read the buyer’s guide and frequently asked questions for helpful tips. Also, have a look at our comparison chart to help steer your decision-making.



  • Max lumens 2,800
  • Max beam distance 1,247 ft. (380 m)
  • Max runtime 42 hrs.
  • Lighting modes Five brightness levels and strobe
  • Battery Included 21700 rechargeable li-ion battery
  • Bulb type Luminus SFT70 LED
  • Color temperature Around 6,500K
  • Size Length: 5.74” (145.8mm), head: 1.04” (26.5mm), body: 1.01” (25.7mm)
  • Weight 5.96 oz. (169g) including battery


  • Powerful, uniform 2,800-lumen beam
  • USB-C charging
  • Long battery life
  • Great user interface


The Fenix PD36R Pro is the latest evolution of our favorite overall flashlight on the market. A slightly upgraded model of the also-great PD36R, the PD36R Pro has one big difference that is better, and that is the dual tail switches. The system works like this: One larger tail switch turns the light on and off. The other toggles through the five brightness modes, or, if the light is off, activates the strobe function for self-defense. In the dark, with gloves, or whenever, it’s incredibly easy to manipulate the switches and get the output you want in seconds.

If you prefer the lighting control mounted on the body of the light, the standard PD36R is still available. But I suspect most users will love the upgraded PRO model.

Beyond user experience, the runtime is phenomenal. With the new PD36R PRO in Eco (30 lumens) mode, you can achieve a solid 42 hours of runtime. If runtime is your primary concern, the non-PRO version of this light has a much longer runtime, but lower overall output.

For casual users (occasional camping trips and short bursts of high-output modes), that should amount to months between charges. Our tester has gone more than 2 months without recharging the PD36R PRO with regular usage.

Speaking of modes, the PD36R PRO ranges from a low-end 30 lumens up to a searingly bright 2,800 lumens. At that 2,800-lumen turbo mode, you can easily see objects at 1,247 feet. That’s more than enough for most use cases for recreation in the outdoors. And impressively, the PD36R PRO can maintain that brightness for 3.5 hours.

With an IP68 waterproof rating, it can withstand being underwater up to 6.5 feet for 30 minutes. It’s also dustproof and shock-resistant. One feature I love is how you can easily manipulate between tactical (and strobe-enabling) functions.

Beyond the specs, this is a perfect hand-size flashlight (5.74 inches long, 1.04 inches in diameter) with user-friendly functions. Turn it on and off at the large tail switch, press the smaller tail switch to adjust power, and check the LED near the USB-C charging port when turning the light on for a battery-level indication.

Overall, I think the PD36R PRO is the best flashlight on the market today.

ThruNite Archer 2A V3 Cool White


  • Max lumens 500
  • Max beam distance 93 m
  • Max runtime 51 hrs. (low), 15 days firefly mode
  • Lighting modes Four plus strobe
  • Battery Two AA
  • Bulb type CREE XP-L2 LED
  • Dimensions Length: 6.1, width: 0.86
  • Weight 1.69 oz. (48 g)


  • Long battery life
  • Small and light
  • Enough power for indoor or close outdoor use
  • Affordable


While the ThruNite Archer (30) lacks a few of the higher-end features of other lights on this list, it comes in at an absolutely excellent price of just 30. For that, you get a quality CREE XP-L V6 LED light source with a maximum power of 500 lumens. While that number may not look impressive, it’s way more than enough for most uses. Using two AA batteries, it has a runtime of up to 4 days on firefly mode and 11 hours on medium (75 lumens).

You heard that right — this flashlight does use AA batteries. That certainly brings down the price compared with high-end rechargeables and costs money to operate. Our team prefers rechargeable flashlights for several reasons we’ll get into below. But flashlights with disposable (or rechargeable) AA batteries are very easy to repower on backcountry trips — just bring a couple of extras.

At 30, the ThruNite Archer has earned a remarkable 4.5 stars with more than 1,800 ratings on Amazon. It’s worth noting that previous versions of this article did list even cheaper flashlights. But after significant testing, I found those very cheap lights simply did not perform up to our minimum standards. The ThruNite Archer, while still affordable, definitely meets the criteria of durability, a useful beam, and ease of use while still being easy on the wallet.



  • Max lumens 3,000
  • Max beam distance 220 m
  • Max runtime 37 hrs.
  • Lighting modes Five brightness levels and strobe
  • Battery Built-in li-ion battery
  • Bulb type 2x Luminus SST40 LED
  • Dimensions Length: 135.6 mm (5.34), width: 31.4 mm (1.24)
  • Weight 4.37 oz. including battery


  • Slim design with clip
  • OLED screen displays remaining time, output
  • 3,000-lumen output
  • Long throw
  • Long battery life


A new addition to the best flashlights of 2023, the NITECORE EDC27 first launched at SHOT Show 2023. This light dazzled folks with a wonderful design and massive light output. If you can get your hands on one (it’s still selling out quickly with every batch produced), this light is the latest and greatest EDC flashlight on the market. I expect it to be popular for a long time.

Let’s begin with the design. The NITECORE EDC27 is a flat flashlight with a clip. That means it fits easily in your It will even work in most knife s on pants, making it a dream to carry. To turn it on, press a large tail switch. Next to that switch is a smaller tail switch. Once on, depress that smaller switch to flip between modes. Or, you can press the smaller tail switch when the light is off to fire the strobe or momentary on modes. For the EDC user who may need to use the light for self-defense, this is a slick interface that should result in never hitting the wrong button for the needed use.

Next, a quick look at the specs reveals class-leading numbers. A top output of 3,000 lumens and a 200m range will serve all but the most dire search and rescue, hunting, or tactical needs. And a run time of 37 hours on low provides a good, long life for the vast majority of uses.

Finally, the light has an easy-to-read OLED display. It reads run time and current lumen output. This takes the guesswork out of recharging the battery and lets the user know exactly what they can expect the light to do.

Overall, the EDC27 is an incredible new flashlight. I haven’t had enough time testing it to say it will outperform our current top pick, but it certainly should give Fenix a run for its money.

NITECORE P20iX 4000 Lumen USB-C Rechargeable Tactical Flashlight


  • Max lumens 4,000
  • Max beam distance 241 yds.
  • Max runtime 350 hrs.
  • Lighting modes Six plus strobe
  • Battery Nitecore 21700 i Series (other options available)
  • Bulb type 4 x CREE XP-L2 V6 LEDs
  • Dimensions Length: 5.57, height; 1.25
  • Weight 4.09 oz.


  • Very powerful
  • Operates on various battery types
  • Extremely long runtime
  • USB-C Rechargeable


NITECORE discontinued one of our previous favorites (the i4000R) but replaced it with an even better, more powerful torch. A strong contender for the best overall flashlight, the new NITECORE P20IX (120) is one of the best flashlights on the market in terms of overall performance.

It’s slightly larger than our 2021 winner from Fenix, however, so it’s less suitable for hikers, hunters, or others who value light weight and small size.

That said, the new version shaves half an ounce and half an inch off the previous model, coming in at 4.06 ounces and 5.57 inches long. So it’s edging closer and closer to a.friendly size.

The i4000R punches through the darkness with 4,000 lumens on turbo mode for up to 30 minutes. That’s enough to light up objects 250 yards away, so it should be high on your list for performance alone. importantly, it has four continuous and strobe modes, ranging all the way down to the 2-lumen ultralow mode that provides light for up to 350 hours.

It runs on a rechargeable battery that powers four CREE XP-L2 V6 LEDs. This setup provides exceptional versatility for everyone from campers and hunters to search-and-rescue and tactical uses. The user interface is great, providing easy access to toggle between modes (like its turbo output and strobe mode) through a dedicated button separate from the rear tail switch.

While this is a high-end flashlight, it’s absolutely worth the price for those who need a powerful, reliable flashlight with the potential to hold up to extremes.

Olight Warrior X Pro


  • Max lumens 2,250
  • Max beam distance 500 m
  • Max runtime 8 hrs.
  • Lighting modes 2
  • Battery 5,000mAh 21700 battery
  • Bulb type High-performance neutral white LED
  • Dimensions Length: 5.87, width: 1.03
  • Weight 8.43 oz.


  • Magnetic charging requires special cable
  • No low-power mode
  • Narrow beam hard to use at close range

With a maximum output of 2,250 lumens (and the ability to project it a whopping 500 m), the Warrior X Pro (120) packs a heck of a punch. For most people, that level of output is overkill. But for those who need to sweep large expanses of nighttime terrain (like search-and-rescue personnel), this kind of power can come in handy.

Those are pretty wild specs for a flashlight that weighs just 8.43 ounces and measures less than 6 inches in length. It runs on a 5,000mAh rechargeable battery. You can recharge it anywhere you have a 12-volt USB outlet or recharger. It comes in three additional colors.

While the Olight Warrior X Pro does give you excellent high-power performance, it’s weaker in the runtime category. That’s because its lowest power output is 300 lumens — more power than you usually need around a campsite. So for people looking for better runtime with lower outputs, there are better choices.

For search and rescue personnel, or anyone who needs a reliable tactical flashlight for nighttime scanning, however, this is one of the best flashlights you can buy.

LEDLENSER MT10 Flashlight


The Ledlenser MT10 rechargeable flashlight (90) competes well with the Fenix above, and on paper, it in some ways outshines the competition. The specs put these two top flashlight choices in similar categories, and I expect users will love them both.

One thing I love about the MT10 over the Fenix PD36R is the Ledlenser Advanced Focus System. This simply means you can adjust between a broad floodlight and a long-distance beam in an instant. Simply press the front bezel forward, and the light focuses tighter and tighter.

It works extremely well in the field. We’ve used it to find our way out of the woods while bushwhacking during elk hunts in the Rocky Mountains and appreciated the ability to scan far hillsides for trails and landmarks with the max 1,000 lumens and 180 m of throw.

The Ledlenser MT10 also gives a great useable low light, running up to 144 hours at 10 lumens. It has a mid-power setting, but the brand doesn’t share specs on it. But at its middle setting, you get nice light for hiking and good runtime. I’ve only charged this flashlight twice in about a year of testing.

Speaking of charging, this light charges off a micro-USB cable. I love that fact, as it’s a common size and doesn’t require you to carry an oddball cable on trips.

Overall, the MT10 is one of the best flashlights you can buy, with most of the features an outdoor user will require. It’s reasonably priced as well, given its strong power and battery. I also appreciate its simple user interface.

The only ding against this compared with the more expensive Fenix is the build feels a little less robust (it’s IP54-rated for dust and water splashes and rain but is not fully waterproof). I also liked the color rendering a bit better on the Fenix. But the Ledlenser MT10 puts up a great fight.

Blackfire Rechargeable Weatherproof Magnetic Flashlight With Lantern


  • Max lumens 500
  • Max beam distance N/A
  • Max runtime 30 hrs.
  • Lighting modes Four, plus lantern
  • Battery Rechargeable lithium-ion
  • Bulb type LED
  • Dimensions Length: 5.5, width: 1.5
  • Weight 6.9 oz.


Blackfire, a newer division of Klein Tools, is making some nice flashlights these days. Overall, the BBM6412 is an excellent upgrade to our previous top flashlight for mechanics.

At around the 40 range, this light packs in a ton of performance that makes it fit for both the garage and the wilderness. It has a top output of 500 lumens — while not super powerful, that’s certainly sufficient for use on the trail and around the campsite. And it’s more than enough power when working under the hood of your truck.

Where it really stands out is its magnetic base and side-throw lantern. This work light illuminates a larger area with soft, useful light at five brightness settings. In our testing, it was the perfect companion while checking for loose wires under the hood of a truck in the dark. And it’s capable of big tasks, too. It’ll kick out 375 lumens for 10 hours in work light mode or 500 lumens for 7 hours in standard mode.

Our testers also loved the simple, common USB-C connection for fast recharging and the multicolor battery level indicator. Top it off with a glow-in-the-dark bezel that makes it easy to find in a center console in the dark, and you’re looking at a lot of flashlight for not much money.

Flashlights Comparison Chart

FlashlightPriceMax Output (Lumens)Max Beam DistanceBattery TypeWeight
Fenix PD36R PRO 120 2,800 1,247 ft. (380 m) Included 21700 rechargeableli-ion battery 5.96 oz. including battery
ThruNite Archer 2A V3 Cool White 30 500 93 m 2 x AA 1.69 oz.
NITECORE EDC27 90 3,000 220 m Built-in li-ion battery 4.37 oz. including battery
Nitecore P20iX 4000 Lumen USB-C Rechargeable Tactical Flashlight 120 4,000 241 yds. Nitecore 21700 i Series 4.09 oz.
Olight Warrior X Pro 120 2,250 500 m 5,000mAh 21700 battery 8.43 oz.
LEDLENSER MT10 Flashlight 90 1,000 180 m Rechargeable lithium-ion 5.5 oz.
Blackfire Rechargeable Weatherproof Magnetic Flashlight With Lantern 42 500 N/A Rechargeable lithium-Ion 6.9 oz.

Why You Should Trust Us

In short, our primary flashlight testers are not just super into the outdoors; they’re also flashlight nerds. We really love the technology that goes into flashlights and headlamps. As the author of this article, I personally spend hours every month testing the newest flashlights to see if they can outperform our favorites listed here.

For the record, it takes a long time and impressive performance for a flashlight to earn a spot in this article. I constantly test new flashlights and updates from our favorite brands and update this article many times each year to keep it up to date with the best flashlights available.

Buyer’s Guide: How to Choose a Flashlight

There are a few important specs to consider when choosing a flashlight: size and weight, max power output (usually noted in lumens), minimum power output, runtime (especially in lower modes), durability, and waterproofness.

Before we get into some of those details, I’d like to share some details about how I chose flashlights to test for this article. And there have been a lot of them.

First, I look for flashlights that work well for both home and outdoor use. This means I look for higher output than flashlights intended primarily for indoor use. I also only include flashlights that can function after at least a 1m drop, are water-resistant, and have a max runtime of at least 8 hours — enough to get you through a summer night at a minimum.

Next comes the question of batteries. Because of the efficiency of modern flashlights, there are now just two real choices: flashlights that run on AA or AAA batteries, or rechargeable flashlights that run off one of many higher-end battery systems and are almost always included in the light. Gone are the days of giant D-cell flashlights. But there is still a significant argument between those who believe disposable batteries or rechargeable batteries are better. I will get into it more below, but our team likes rechargeable batteries more in most cases.

Lumens: Max Output

For most campers, anything over 1,000 lumens is overkill. You’ll often find yourself using much lower settings, especially around camp. However, those big numbers can be nice, especially if you need to see faraway objects.

Battery Life

Another important consideration is if the flashlight uses its own rechargeable battery or if it runs on disposable batteries. Most people will get more value out of a flashlight that offers long runtimes and is easy to recharge.

Battery Type

As noted above, our team prefers rechargeable batteries in most situations. Most rechargeable batteries, such as the 21700 rechargeable li-ion battery included in the Fenix PD36R PRO, offer superior performance to both disposable and rechargeable AA or AAA batteries. But more importantly, flashlights that include this type of high-end rechargeable battery do not have hidden costs. And for those who will use a battery more than casually will find that the cost of batteries will very quickly add up to more than the cost of the flashlight.

Next, rechargeable flashlights generally have a charging port or system built in. As you can see with our choices, our favorite flashlights today use USB-C charging. This is quickly becoming the industry standard as it is much faster than micro-USB charging. And unlike magnetic charging systems (or other proprietary chargers), you can easily find a USB-C cable anywhere and likely own several already.

One final note on AA and AAA batteries. Some folks argue that it is easier to replace batteries in the field than to charge them. Our testers have carried small battery chargers on many adventures, and they work great with flashlights for long trips. For trips over a week or two in length, though, disposable batteries still have an edge.

So keep battery and charging style in mind when you buy a flashlight. It will make a difference when you’re packing for a trip as to how many cables you’ll need to bring, or if you’ll need to buy batteries continually through the life of the product.

However, it’s convenient to quickly change batteries and refresh your flashlight in the field. Both are valid options, but consider how you’ll use the light (and if you mind constantly buying new batteries).

Quality and Output

Modern LED flashlights vary in the quality of their color rendering, meaning you can see color better with some higher-end lights. The best flashlights on the market should always give you a colorized, realistic view.

Better-quality lights also tend to have more efficient LEDs. Some even have “regulators” that electronically manage the power output, resulting in consistent lighting. To expand on that, first understand that most flashlights, even very good ones, lose a little output as they run and deplete the battery. Better flashlights use a regulator to manage this drop-off. Poor flashlights tend to lose power consistently over time, gradually becoming less and less useful as the battery slowly drains.


A lumen is the basic unit of measurement for how bright a light is. The brighter the light, the more lumens it produces. The Merriam-Webster dictionary defines a lumen as “a unit of luminous flux equal to the light emitted in a unit solid angle by a uniform point source of one candle intensity.” For the layperson, a one-lumen flashlight is barely enough to read a typical book at a normal reading distance from the face, or the amount of light of one birthday candle one foot away.

Yes, LED flashlights do get warm if they’re pushed hard enough. For many flashlights, this is a sign the heat sink is working, moving heat away from the delicate electronics inside.

The highest-lumen flashlight currently on the market is the Imalent MS18, which claims a jaw-dropping 100,000 lumens. However, many huge claims like this are questionable. The brightest flashlight I have tested is the Fenix LR50R. It blasts out a verifiable 12,000 lumens and lights objects clearly up to 950 yards away!

EDC is an acronym for “everyday carry.” It refers to the items that you carry around with you on an ongoing basis.

As a philosophy, EDC is built on utility and being prepared for anything. In this case, it represents a flashlight you carry every day with you in case you ever need light in a dark environment.

First and foremost, you’ll want a small flashlight that’ll fit in your. clip to your belt, or fit in your daypack. After that, look for a flashlight with good brightness, long battery life, and easy operation.

1,000 to 2,000 lumens is plenty bright for an EDC. That should give you enough juice to see objects 200 to 300 yards away. Our top choice for everyday carry is the Nitecore EDC27.

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Sean McCoy is the Editorial Director of GearJunkie, and 5 other All Gear websites.

He has been writing about hunting, fishing, trail running, camping, skiing, and more for 15 years.

Prior to GearJunkie, he was the chief photographer for the Virgin Islands Daily News and former Editor In Chief for GearJunkie. Based in Denver, Colorado, McCoy is an avid trail runner, camper, hunter, angler, mountain biker, skier, and beer tester.

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