18650 VS 26650 VS 21700 Battery: What’s The Difference. 26650 battery voltage

650 VS 26650 VS 21700 Battery: What’s The Difference?

The 18650, 26650, and 21700 batteries are all types of rechargeable lithium-ion batteries. They are commonly used in a variety of applications, such as flashlights, power tools, and electric vehicles.

Each type of battery has its own unique characteristics that make it suitable for different applications. In this article, we will discuss the differences between 18650, 26650, and 21700 batteries and how they can be used in various applications.

650 Battery

The 18650 battery is one of the most popular types of rechargeable lithium-ion batteries. It is commonly used in flashlights, power tools, and electric vehicles. The 18650 battery has a diameter of 18mm and a length of 65mm, which makes it relatively small and lightweight. It has a capacity of up to 3,000 mAh and can be recharged up to 500 times. The 18650 battery is also relatively inexpensive and widely available.

18650 Technical parameters

To give you a better understanding, let’s look at the key technical parameters of the 18650 battery.

-Nominal voltage: The battery has

-Capacity: The capacity of the 18650 battery is up to 3,000 mAh.

-Recharge cycles: The battery can be recharged up to 500 times.

-Size: The 18650 battery has a diameter of 18mm and a length of 65mm.

-Charging voltage:The charging voltage of the 18650 battery is 4.2V.

-Charging current: The battery has a charging current of 0.5C.

-Minimum discharge current: Its minimum discharge current is 1C

-Charging time: It takes approximately 3 hours for the cell to be fully charged

-Battery cell weight: The average weight of this battery cell is 48g

-Lifespan: The battery has a lifespan of between 300 to 500 cycles

-Charge methods: The cell uses constant current (CC) and constant voltage (CV) charging methods.

-Storage temperature:The 18650 battery should be stored at a temperature between.20°C and 45°C.

650 Battery

The 26650 battery is a larger version of the 18650 battery. It has a diameter of 26mm and a length of 65mm, making it slightly larger and heavier than the 18650 battery. The 26650 battery has a capacity of up to 6,000 mAh and can be recharged up to 500 times. It is more expensive than the 18650 battery but is still widely available.

26650 Technical parameters

Here are the key technical specifications of the battery.

-Nominal voltage: The battery has a nominal voltage of 3.7V.

-Capacity: The capacity of the battery cell ranges between 3000 mAh to 3100 mAh.

-Recharge cycles: The battery cell can be recharged up to 2000 times.

-Size: The 26650 battery has a diameter of 26mm and a length of 65mm.

-Charging voltage: The charging voltage of the 26650 battery is 4.2V.

-Battery weight: It approximately weights 92g

-Pulse discharge current: The pulse discharge current of the 26650 battery is up to 10C.

-Charge methods: The cell uses CC and CV charging methods.

-Storage temperature: The 26650 battery should be stored at a temperature between.20°C and 45°. Starts discharging at temperatures of between 20°C and 60°C.

700 Battery

The 21700 battery is the newest type of rechargeable lithium-ion battery. It has a diameter of 21mm and a length of 70mm, making it slightly smaller and lighter than the 18650 and 26650 batteries. The 21700 battery has a capacity of up to 4,000 mAh and can be recharged up to 500 times. It is more expensive than the 18650 and 26650 batteries but is still widely available.

21700 Technical specifications

Here are the key technical specifications of the battery.

-Nominal voltage: The battery has a nominal voltage of 3.7V.

-Capacity: The capacity of the cell is between 3900 and 5600 mAh.

-Recharge cycles: The battery has charge and discharge cycles of between 500 to 2000.

18650, 26650, 21700, battery

-Size: The battery has a diameter of 21mm and a length of 70mm.

-Charging voltage: The charging voltage of the 21700 battery is 4.2V.

-Battery weight: It approximately weights 60g

-Capacity discharge_ It has a discharge is 0.2C

-Pulse discharge current: The pulse discharge current of the 21700 battery is up to 10C.

-Charge methods: The cell uses constant current (CC) and constant voltage (CV) charging methods.

18650, 26650, 21700, battery

-Charging time: The battery takes approximately between 2.5hrsto 3 hrs to be fully charged.

-Charge density: It has a charge density of 10.5-13.7Wh

-Storage temperature: The 21700 battery should be stored at a temperature between.20°C and 55°C. Starts discharging at temperatures of between 20°C and 60

650 VS 26650 VS 21700 Battery: What’s The Difference?

Let’s now compare the three battery cells using various key parameters. From this detailed comparison, you will know which one is more suitable for your application.

Nominal voltage

The nominal voltage of a battery refers to the voltage at which the battery is designed to operate. All three batteries have an average nominal voltage of 3.7V. There is no significant difference in terms of the nominal voltage of the three batteries.


The capacity of a battery refers to the amount of energy it can store. The 18650 battery has a capacity of up to 3,000 mAh, while the 26650 and 21700 batteries have capacities of up to 6,000 mAh and 4,000 mAh, respectively. This means that the 26650 and 21700 batteries have higher capacities than the 18650 battery.

Recharge cycles:

The recharge cycles of a battery refer to the number of times it can be recharged before it needs to be replaced.

It is the lifespan of a battery cell.

From the specifications above, the 26650 and 21700 have a way superior charge cycle than the 18650 battery. cell.


The size of a battery refers to its diameter and length. The 18650 battery has a diameter of 18mm and a length of 65mm, while the 26650 and 21700 batteries have diameters of 26mm and 21mm, respectively, and lengths of 65mm and 70mm, respectively. So, if your application is quite sensitive on size, you will have to compare the three and choose the right size from the three.


The weight of a battery refers to how much it weighs. The 18650 battery has an average weight of 48g, while the 26650 and 21700 batteries have weights of 92g and 60g, respectively. This means that the 18650 battery cell is the lightest of the three. Are you curious about the weight of the cells? You now know the right option.

Discharge current

Discharge current is the amount of current that can be drawn from the battery. The 18650 battery has a minimum discharge current of 1C, while the 26650 and 21700 batteries have pulse discharge currents of up to 10C. This means that the 26650 and 21700 batteries can provide more power than the 18650 battery.

Charging method

As we have seen, all three batteries use constant current (CC) and constant voltage (CV) charging methods. This means that they can be charged using the same type of charger.

Storage temperature

The storage temperature of a battery refers to the temperature at which it should be stored. The 18650, 26650, and 21700 batteries should be stored at temperatures between.20°C and 45°C.20°C and 45°C, and.20°C and 55°C, respectively. This means that the 21700 battery can be stored at a higher temperature than the other two batteries.

Charging time

How long does it take to charge these battery cells? The 18650 battery takes approximately 3 hours to be fully charged, while the 26650 and 21700 batteries take approximately 2.5 hours and 3 hours, respectively. This means that the 21700 battery has a slightly longer charging time than the other two batteries.

But generally, there is a very small difference when it comes to the charging duration of the three cells.

Chemical composition

Of course, the three are all lithium-ion batteries, but they have different chemical compositions. The 18650 battery is composed of lithium cobalt oxide (LiCoO2), while the 26650 and 21700 batteries are composed of lithium iron phosphate (LiFePO4). This means that the 26650 and 21700 batteries are more stable and have a longer lifespan than the 18650 battery.

Charge density

The charge density of a battery cell is the amount of energy it can store per unit of weight. The 18650 battery has a charge density of 8.5-10.5Wh, while the 26650 and 21700 batteries have charge densities of 10.5-13.7Wh and 10.5-13.7Wh, respectively. This means that the 26650 and 21700 batteries have higher charge densities than the 18650 batteries.

Cutoff voltage

The cutoff voltage of a battery refers to the voltage at which it should be disconnected from the charger. The 18650 and 26650 batteries have cutoff voltages of 2.5V, while the 21700 battery has a cutoff voltage of 2-2.5V. This means that the 21700 battery has a slightly lower cutoff voltage than the other two batteries.

Inner resistance:

The inner resistance of a battery refers to the resistance of the cell when it is in use. The 18650, 26650, and 21700 batteries have inner resistances of between 10-20mΩ, 10-20mΩ, and 5-10mΩ, respectively. This means that the 21700 battery has a lower inner resistance than the other two batteries.

Continuous discharge current

This refers to the amount of current that can be drawn from the battery continuously. The 18650 and 26650 batteries have continuous discharge currents of 1C, while the 21700 battery has a continuous discharge current of 0.2C. This means that the 21700 battery can provide less power than the other two batteries.


When it comes to the usage, the 18650 battery is mostly used in flashlights, power tools, and electric vehicles. The 26650 battery is used in high-powered applications such as electric bikes and scooters. The 21700 battery is used in applications that require a higher capacity and longer lifespan, such as solar energy storage systems. So, you can choose the right battery cell depending on your application.


What about the price of the battery cell? The 18650 battery is the most affordable of the three, while the 26650 and 21700 batteries are more expensive. So, if you are looking for a budget-friendly option, then the 18650 battery is your best bet. However, keep in mind that the price will always depend on the quality and brand of the battery. It will also depend on the battery supplier that you choose.


Now let’s look at the most common questions that people tend to ask with regards to the 18650, 26650, and 21700 batteries.

Are AA batteries the same as 18650?

No, AA batteries are not the same as 18650 batteries. AA batteries are smaller and have a lower capacity than 18650 batteries. The two also tend to have different chemical composition.

Can I use a 26650 battery in place of a 18650 battery?

Yes, you can use a 26650 battery in place of a 18650 battery. However, keep in mind that the 26650 battery is larger and heavier than the 18650 battery.

Can I use a 21700 battery in place of an 18650 battery?

Yes, you can use a 21700 battery in place of a 18650 battery. But you should keep in mind that the 21700 battery is larger and slightly heavier than the 18650 battery. So, your device or application should be designed to keep up with these new changes.

Why are the 18650 batteries so popular?

The 18650 battery is popular because it is relatively small and lightweight, has a high capacity, and is relatively inexpensive. It is also widely available and can be used in a variety of applications.

What makes 18650,21700 and 26650 batteries explode?

The 18650, 21700, and 26650 batteries can explode if they are overcharged, short-circuited, or exposed to extreme temperatures. It is important to use the right charger and follow the manufacturer’s instructions when charging these batteries.

Is C battery the same as 26650 battery?

No, C batteries are not the same as 26650 batteries. Even though they are of the same size, C batteries are not rechargeable and have a much lower capacity than 26650 batteries.


Well, there you have it. Now you know all about the 18650, 26650, and 21700 batteries. You know their key technical specifications, how they compare to each other, and what applications they are suitable for. So, you can now make an informed decision when choosing the right battery cell for your application. And planning to buy these rechargeable lithium-ion batteries in China? Consider contacting ICRFQ. We are a reputable supplier of 18650, 26650, and 21700 batteries. We offer high-quality products at competitive prices. Contact us today for more information.

If you want to find more Electronic Components Distributors, please check out the following articles:

650, 3.2V, 3300 mAh, 2C LFP Cells (4 pcs)

The Bioenno Power 26650, 3.2V, 3300 mAh LiFePO4 cells are excellent for a variety of applications including for assembling a variety of LiFePO4 battery packs. These cells provide 2C maximum continuous discharge current. The cells are sold in a pack of 4. Please note that these cells must be assembled in combination with a PCM/BMS into a battery pack by qualified users. The cells are not intended for use without protection.

Rated Capacity: 3300 mAhNominal Voltage: 3.2VDCCharging Voltage: 3.65VDCInternal Impedance: 40 milli-ohmsStandard Charge: Constant Current at 0.2C, Constant Voltage at 3.65 VDC, 0.01C cut-offStandard Discharge: Constant Current at 0.2C, Ending Voltage: 2.0VDCMaximum Continuous Charge Current: 1CMaximum Continuous Discharge Current: 2COperation Temperature: Charging. 0 to 45 deg C; Discharging.20 deg C to 60 deg CStorage Temperature Range:.20 deg C to 25 deg CCell Dimensions: 65 mm x 26 mm (Height x Diameter)

Shipping: Standard Returns/Exchange: 30 Days Warranty: 2 Years Standard Lithium Iron Phosphate Battery Warranty

Contact Us

For Sales Team: sale@bioennopower.com Toll Free: (888) 336-7864(888) 834-1986 (714) 234-7363 Fax Number: (714) 988-4223

For Technical Support (email only): sale@bioennopower.com

OFFICE VISIT BY APPOINTMENT ONLY Bioenno Power / Bioenno Tech LLC 3657 W. McFadden Ave. Santa Ana, California 92704 USA

Specification of A123 ANR26650 26650 LiFePO4 Battery Cell

A123s high-performance Nanophosphate® lithium iron phosphate (LiFePO4) battery technology delivers high power and energy density combined with excellent safety performance and extensive life cycling in a lighter weight, more compact package. The cells have low capacity loss and impedance growth over time as well as high usable energy over a wide state of charge (SOC) range, allowing our systems to meet end-of-life power and energy requirements with minimal pack oversizing.

Key Features and benefits

-Excellent abuse tolerance and superior cycle life from A123’s patented Nanophosphate lithium ion Chemistry.High power with over 2,600W/kg and 5,800 W/L, 10 seconds, 50%SOC.High usable energy over a wide state of charge (SOC) range



Advanced lead acid replacement batteries for: Datacenter UPS, Telecom backup, IT backup, Autonomously guided vehicles (AGVs), Industrial robotics and material handling equipment, Medical devices GOVERNMENT SOLUTIONS

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Everything You Need to Know About the 18650 Battery

This article tells you everything you need to know about 18650 batteries. We’ll talk about different types, features, charging, lifespans, and our recommendations for batteries and chargers.

  • What is an 18650?
  • Recommended 18650 Batteries
  • Various Battery Sizes
  • Comparing 18650s to Other Common Batteries
  • 18650 Terminology
  • Protected vs Unprotected 18650 Batteries?
  • How much power does an 18650 have?
  • How many times can you recharge an 18650 or other battery?
  • How frequently should I recharge my 18650?
  • How do I know my 18650 is Dying?
  • How can I measure the quality of an 18650 if I am unsure of the age of a battery?
  • 18650 Battery Chemistry
  • What are 18650 batteries used for?
  • What is the best travel 18650 battery?
  • What 18650 Brands are Best?
  • s

What is an 18650?

An 18650 is a lithium ion rechargeable battery. Their proper name is “18650 cell”. The 18650 cell has voltage of 3.7v and has between 1800mAh and 3500mAh (mili-amp-hours).

18650s may have a voltage range between 2.5 volts and 4.2 volts, or a charging voltage of 4.2 volts, but the nominal voltage of a standard 18650 is 3.7 volts.

There are two types; protected and unprotected. We absolutely recommend protected cell 18650 batteries. Protected cells include a protection circuit that stops the cell from being overcharged.

Unprotected cells can be overcharged and burst and potentially cause a fire unless there are specific electronics to protect the battery. The popular LG HG2 and INR and Samsung 25r and 35e are UNPROTECTED batteries, only use them in a device designed to use unprotected 18650s.

We also recommend you stick with high quality brand name 18650s. Knock offs may lie about high mAh (capacity).

The average 18650 battery charge time is about 4 hours. Charge time can vary with amperage and voltage of the charger and the battery type.

Recommended 18650 Batteries

Battery Make and TypeAll are 3.7v Lithium Ion (Li-ion) Max Milliamp hours NotesShop around for best price
Orbtronic 18650 Protected #ORB3500P 3500 mAh Only available direct from vendorgood price
Olight ORB-186C35 Protected #ORB-186C35 3500 mAh Ok price
Nitecore 18650 NL1835RProtected #NL1835R 3500 mAh Good for travel, expensive.Has micro-USB charger port so it can charge itself with a cable/USB port
Panasonic NCR18650BD ButtonProtected#NCR18650-BD 3180mAh Less expensive PROTECTED and good for high drain devices.
Panasonic NCR 18650 3400mAh NOT PROTECTED#NCR18650B-3400 3400 mAh Less expensive but is NOT PROTECTED. Use carefully.
Panasonic NCR18650BE NOT PROTECTED#NCR18650BE-3200 3200 mAh Less expensive but isNOT PROTECTED. Use carefully.

Various Battery Sizes

The following is a picture showing various battery sizes. The 18650 is 1170 cubic mm, the 14500 and AA are 700 cubic mm, the AAA is 467 cubic mm.

Note the 14500’s cannot be used in all AA devices unless they support both 3.7 and 1.5 volt batteries. The 21700 at 1550 cubic mm, is larger than the 18650 battery – the 21700 and 18650 is not interchangeable.

18650 Terminology

A battery might say protected mode 3.7v 18650 3000 mAh low self discharge for high drain devices. What does that all these features mean?

  • “protected mode” means it has an overcharge and overdraw circuit protection built in (more info below).
  • “3.7v” – is the optimal or peak voltage. It will drop as you use the battery.
  • “3000 mAh” measures the amp hours the battery can provide. A higher number is better. The highest realistically available on an 18650 today is about 4000 mAh, anything higher than that is marketing hype.
  • “Low self discharge” is a good thing. That means it will hold a charge in storage. The less it loses in storage the more charge will be left for you to run your flashlight or other device.
  • “for high drain devices” – the battery is optimized for high drain devices. These are devices that use a lot of power very fast, such as RC toy car.

Protected vs Unprotected 18650 Batteries?

Protected 18650 batteries have an electronic circuit. The circuit is embedded in the cell packaging (battery casing) that protects the cell from “over charge”, heat or “over discharge”, over current and short circuit. A 18650 protected battery is safer than an 18650 unprotected battery (less likely to overheat, burst or start on fire).

Unprotected 18650 batteries are cheaper, but we do not recommend their use. Unprotected batteries should only be used where the load/draw and charging is externally monitored and controlled. The protected batteries normally have a “button top”, but check the specifications to make sure. Generally 18650 flat top batteries do not include the protection circuit.

If any 18650 battery is damaged or looks corroded or appears to be leaking, get rid of it at a battery recycling center. Be safe.

How much power does an 18650 have?

A 3.7v a 3400mAh 18650 stores about 2 aH to max of 3.5 aH. It can store about 10 to 13 watt hours. A small air conditioning unit that can cool about 9000 BTU uses about 1100 watts per hour. So it would take more than 110 of the 18650 batteries to run the air conditioner for 1 hour.

In comparison you would need three 12v 40 amp car batteries. But 110 18650s are smaller than three car batteries.

How many times can you recharge an 18650 or other battery?

Recharge cycles vary and are limited. Think of it like a bucket. The trick is that the bucket also gets filled with a tiny bit of other junk over time, so there is less room. As the battery is reused (recharged), the battery degrades due to oxidation and electro-chemical degradation.

This happens to any rechargeable battery such as an 18650, 21700, 26650, 14500, AA, AAA or even a car battery. They can only be recharged a limited number of times.

You want to select rechargeable batteries that can be recharged many times. We specifically recommend 18650’s because they have the ability to be recharged 300 to as many as 2000 times.

How frequently should I recharge my 18650?

The way you recharge your battery impacts the life of the battery. If you can measure it, you want to deplete from 3.7v down it to about 3v before you recharge. If you are not sure, use the device until it indicates a battery needs to be replaced. For a flashlight, run it till the light is dim or goes out.

A good charger will tell you the voltage of the battery so you can eventually get a sense of the life of the battery in various devices. If you recharge too frequently you “use up” the life without a return.

Some people don’t let it dip below 3.3v (or even higher). Each brand and model of 18650 has different maximum cycles. So this is really a process of matching your device and usage to the life cycle of the battery.

Be aware that an 18650 battery that drops below 2.5v may “lock” the device so it can’t be used. The “lock” function happens in devices such as vaping devices.

How do I know my 18650 is Dying?

Here is a list of 7 ways you can tell if you need to get rid of an 18650 (or other rechargeable battery). Look through these to determine if your 18560 is nearing the end of its life and needs to be retired:

  • The battery will lose a charge on the shelf must faster than normal. It loses it’s charge after a couple of days or even worse overnight.
  • The battery gets hot when charging or discharging, warmer than normal.
  • You have used the battery frequently over 2 to 3 years.
  • The battery can hold less than 80% of its original capacity.
  • Recharge time gets abnormally long.
  • If there is ANY cracking or deformation in the battery.

These are the 6 signs your 18650 is dead and it is time to get a new one. If you ignore these warning signs you risk fire or even having the battery explode while being recharged.

How can I measure the quality of an 18650 if I am unsure of the age of a battery?

A trick is to buy one or two similar 18650s and mark them “new” with a Sharpe (or label them A, B, C, etc). Then use them and compare their voltage and discharge rates with the questionable 18650s.

Basically you are comparing good vs unknown this way.

18650, 26650, 21700, battery

You can also gauge temperature this way. Charge both the new and unknown one to see how hot the new one is compared to the one you are unsure of.

18650 Battery Chemistry

There are a number of different chemical combinations for 18650 batteries. We recommend that you FOCUS on protected mode, the chemistry can change and isn’t always reported. Many simply say Li-ION (meaning Lithium Ion).

There are actually a number of Li-Ion batteries. Here are some of the current “types”. Depending on your device type one might be better than the others.

  • LiFePO4 which is Lithium iron phosphate
  • also known as IFR or LFP or Li-phosphate
  • LiMn2O4 which is Lithium manganese oxide
  • also known as IMR or LMO or Li-manganese (high amp draw)
  • LiNiMnCoO2 which is Lithium manganese nickel
  • also known as INR or NMC (high amp draw)
  • LiNiCoAlO2 which is Lithium nickel cobalt aluminum oxide
  • also known as NCA or Li-aluminum
  • LiNiCoO2 which is Lithium nickel cobalt oxide
  • also known as NCO
  • LiCoO2 which is Lithium cobalt oxide
  • also known as ICR LCO Li-cobalt

What are 18650 batteries used for?

Flashlights, electronics, laptops, vaping and even some electric vehicles use 18650s. The Tesla uses 7180 of these batteries. Many high lumen flashlights such as the Thrunite TC15 v3 (best buy) or Fenix PD36 TAC (mo43 durable) use the 18650 or the even larger 21700 flashlights like the Nitecore P20iX a 4000 lumen flashlight.

Laptops and other electronic devices use one or more 18650’s and have recharging electronics built in. 18650’s are also used in vaping (smoking) devices.

18650s are are generally Lithium Ion batteries. If you are familiar with electronics you can change out some battery packs manually, but be careful – using the wrong type of 18650 or using it incorrectly can cause a fire.

Which is the Best 18650 Battery?

Overall best 18650 battery – The Orbtronic 18650 battery. This is an 18650 3.7v 3500mAh Protected cell. This is a high drain battery. We like it but it is expensive.

Best low cost 18650 battery – The Olight ORB-186P26 18650 2600mAh 3. The Panasonic 18650 is an 18650 3.7v 2600mAh Protected cell. This battery is less expensive and slightly lower amp hours than the Orbtronic. Also, this lower cost protected 18650 battery is still more expensive than the unprotected ones.

What is the best travel 18650 battery?

Nitecore NL1834R (currently not available on Amazon but available directly from Nitecore). This is an 18650 3.7v 3400mAh protected cells with a built-in micro-USB charger. It is a few dollars more, but it allows you to charge it on the go and not have to carry a dedicated charger. The unit we have has slightly different packaging.

The cheapest decent one is the Titanium Innovations 18650 at 2600mAh. It won’t last as long as the 3400 mAh Nitecore but is 1/2 the price.

What 18650 Brands are Best?

The Orbtronic, Olight, Samsung, LG, Panasonic, Surefire, ThruNite and Nitecore are good reliable 18650 rechargeable cells. Be sure to buy them from a reputable source such as BatteryJunction or direct from the manufacturer. Note: Amazon stopped selling 18650s.

We don’t use the lower voltage and amperage 18650s, because they have lower amp hours and low peak wattage and lower sustained wattage.

We are willing to pay a few more dollars for the longer life, higher capacity and better quality.

650 Battery Charger

18650 batteries are rechargeable, so you will need a good charger. We use two different 18650 chargers.

The best 18650 battery charger is the Nitecore Ci4 because it can charge pretty much anything.

Specifically, it supports: lithium ion 26650, 22650, 21700, 18650, 17670, 18490, 17500, 18350, 16340 (the 16340 is also known as RCR123), 14500, 10440 and Ni-MH and Ni-Cd AA, AAA, AAAA, C rechargeable batteries. This is our favorite charger for the 18650s.

Our runner up and “best buy” is the XTAR X4 Charger. It is a USB powered 18650 charger. It charges the batteries with any USB power source. This unit is dependent on the power source, and is a bit more expensive.

It has an LCD display for charging status. A 2amp interface yields slower charge speeds. Even the 5amp is slow because it charges at.5 amps. We have used the XTAR and Nitecore with a Nektek solar panel that has a 2amp USB interface and it has consistently worked.

650 Flashlight

The best mid priced 18650 flashlight is the Thrunite TC15 2403 lumen flashlight. It is about 1/2 the price of the PD36 and but a bit less bright. It is a GREAT buy (we have the older TN12 in emergency kits). We suggest two of these instead of one of the Fenix.

It has the following modes: Strobe (975 lumens for 226 minutes), Turbo (975 lumens for 126 minutes), High (652 lumens for 199minutes), Medium (266 lumens for 9.7 hrs), Low (19 lumens/177 hrs) and Firefly(0.29 lumens for 62 days) and it can charge itself with a USB power source. It is waterproof (IPX8) and has a max throw of 223m (764ft).

The toughest 18650 flashlight is the Fenix PD36 TAC. It is not cheap but it is durable and very bright, and has a clip. The light level is 1000 lumens, and it is water resistant to IPX8. This is a “duty” quality flashlight.

The PD36 TAC offers five different brightness levels and strobe:

  • Turbo: 3000 lumen – 1 hr 30 min
  • High: 1000 lumen – 3 hr 15 min
  • Medium: 350 Lumen (8hr 24min)
  • Low 150 lumen – 18 hr 45 min
  • Eco: 30 lumen – 160 hr
  • STROBE (about 3hrs 2000 lumen)

It has a 300 yard or 274 meter throw.

Both the Fenix PD36 or TN15 are great LED Flashlights that use the powerful 18650 battery.

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1 Комментарии и мнения владельцев

August, can you kind of put this in ‘plain English’ for us less tech savvy folks? Are these better than say, nicad batteries? longer life usage wise as well as recharge times wise? Are they more cost effective than other rechargeables? I don’t mind a larger up front cost if it is going to save me more money in the long run. DH uses rechargeable batteries for his work equipment (cheaper stuff, but company reimburses him) and if we can find something more cost effective, that would be great.

Good questions and thank you for the kind words. 1st off I would not switch devices that use AA or AAA to 18650 unless it was an EVERY DAY use. I might use up the old AA or AAA batteries first before considering switching. Remember these are completely different sizes, and weights. But if you have a need for a very bright flashlight or a device that uses the 18650 go for it. They can be recharged and are readily available from dozens of manufacturers and are likely to only get better over time. As an example I would recommend the ThruNite TN12 or Fenix PD35 to a police officer hands down. It has more power so will last longer in use. Nicad (NiCD), Lithium ion, Nickel-Metal Hydride (NiMH),lithium polymer, alkaline and lead/sulfuric acid in a 12volt car battery — are all ways to store energy. Alkaline and straight lithium (like Energizer Ultimate) are NOT rechargeable. We like the non-rechargeable Energizer Ultimate (lithium) over the other alkaline batteries because they are much less likely to leak/corrode. Also the Energizer Ultimate has a 20 year shelf life, so is great for emergencies. Some of the rechargables have longer shelf life too. Again you need to compare the battery to your use. 18650’s are designed for use – not shelf storage. Are these better than say, nicad batteries? longer life usage wise as well as recharge times wise? Not Necessarily, you have to read the specs to confirm. Some of the extreme drain rechargeable batteries will only recharge 100 to 500 times where a more normal high drain could be recharged 2000 times. This matters if you use a device every single day. The AA will last longer for the same amount of light than AAA, and an 18650 will last even longer (see the table). The 18650 has 10x the wattage capacity as the lower end AAA and the 18650 is 3x to 4x the capacity of the AA. Are they more cost effective than other rechargeables? Again unless you have a need stick with AA or AAA rechargeable batteries. The Eneloop AA is a better buy if you don’t have a direct need. It can be recharged 2100 recharge cycles (2100 times). So it would last 4 to 5 years of recharging with every day recharging. Amazon has good rechargeables also, but they are almost the exact same price as the name brand Eneloop. Here is more info on our AA, AAA and chargers- https://commonsensehome.com/best-battery-chargers/ Overall, we recommend any rechargeable including: car batteries, NiMH, NiCD and LiPo. The 18650 is rechargeable Lithium Ion. The only thing we recommend the Alkaline for are gifts or devices that are likely to get lost. Whether you are using AA, AAA, 9v, button or a car battery – match the battery to your needs. But note the Energizer Ultimate has more “capacity” than the normal 14500, but it cannot be recharged. We don’t recommend the alkaline AA/AAA batteries they are cheap. BUT an alkaline battery is way more expensive compared to rechargeable after only 2 to 5 recharges. They can be used in high-drain devices (high lumen LED flashlights, digital cameras etc) BUT their life expectancy will be sharply reduced. They also suffer from more temperature sensitivity. And in day to day experience they tend to corrode and fail more frequently.

Hi August, I enjoy your articles and the great information they contain very much and those of your wife also. I just have one small complaint. Your articles can be shared on social media everywhere for people all over the world but you don’t have a print function. Many times I want to print an article to reference later without trying to remember which website it was on. For everyday living commonsensehome would be one of the first places I would look, but for a certain battery I might have to check seventy different sites and no telling how many articles. Please think about adding the print button.

I totally understand your dilemma and we wanted to provide that feature. Laurie and I researched (and regularly check) for a printing plugin. None of the ones we found so far work on all platforms (Windows, unix, Android, iPhone, Apple mac etc). Here are a couple options: (1) In many browsers you can right click and select print (2) cut the entire post and paste it into your favorite editor and print (3) use the specific browser print function.

Hi August, thank you for putting this article together! I bit the bullet and bought a 2018 Lupine Blika headlamp to use on week long ski trips here in Alaska. Really only use the 3 watt output setting, the larger bulbs give an unnecessary amount of light and drain a battery VERY quickly. The battery pack that came with the head lamp is small and I need more capacity but the larger OEM battery packs are prohibitively expensive. Owner’s manual says the OEM battery packs have 18650 batteries in them so I figured I’d just buy 18650 batteries and make up my own battery packs. Discovered when I went shopping for batteries that there are apparently dozens of 18650 battery types/outputs and I have no idea which one to use. The battery voltage in the owner’s manual says 7.2 volts and it has a visual battery level meter built right into the the battery pack. I’m afraid of 2 things: I assume the OEM battery pack has circuitry to give a consistent power output so the light stays near the same brightness for the duration of the battery discharge cycle. If I make up my own battery pack, I’ll lose that circuitry and may toast my very expensive headlamp due to too high or too low power input. Is there a stand alone voltage, wattage unit I can buy to put in line to properly regulate my home made battery pack output? And, which 18650 battery will be the best for my usage? Because I’m carrying them, low weight and high capacity is necessary. Thank you for any answers you have for my above questions and thank you for putting out this great site! Matt Obermiller

Thanks for the positive feedback. In response to your comment, the output must match the unit you are using. The 1860 I note in the article is protected mode, so it will not burn up or draw outside spec (that is the battery side). The headlamp battery pack may have a voltage regulator built in. The only suggestion I have is to tinker; but only if you can afford frying one. A lot of the LED emitters circuits will take any 18650 – but some may damage the circuit without protection on the LED side OR they may accept any voltage and work fine. The little AA flashlight we reviewed, will use either an AA or 14500 which are dramatically different, so the only way to find out is test it. Watch out for overheating and be prepared to fry your electronics. If you succeed (or fail), would you mind writing a guest post on this? I am sure the community would appreciate the information. Regarding weight, all 18650s are all fairly heavy. I have not seen a LIPO 18650 yet, but they might be available somewhere. If you are going for lightweight the Energizer Ultimate Lithium AA are super light but one-time use. You would need an AA based headlamp such as the Fenix HP15 – and then you could pick AA rechargeables such as Eneloop Pro or Tenergy are both good depending on use profile – in your case I think the higher mAh would be better from the Eneloop Pro. It really depends on what you are doing. If you are out for long periods the solar panel and rechargeable AA or 18650 would potentially cut your load (and allow you to charge a cellphone or any other USB device) but only if you carried more batteries than the weight of the solar panel. The nektek is 1.3lbs though so unless you need to charge a lot of stuff and are out for a long time this probably isnt an option. (ounces are pounds) All the best.

18650, 26650, 21700, battery

This is the 1st time I’ve ever heard of these and boy am I confused! I’m guessing that you don’t replace your regular rechargeable AA or AAA batteries with these? I’m going to read up and educate myself. This must be something that preppers are into. Love the preppers but the “prepping” is too overwhelming for me being average 65 year old female. Just had to share. I love reading all of the interesting things that preppers are doing. Thanks for letting me share. Debbie

No worries, Debbie. If a device needs an 18650 battery, it’ll be labeled somewhere that it needs one. No swapping out your current batteries required. It’s just a way to cram more power in a relatively small package. Some preppers use them, I’m sure, but they’re mainly for electronic gadgets that suck a lot of power – like our small LED flashlight that’s bright enough to light up the back of the ten acres from the front of the 10 acres.

Hi August. My question is how do I know if my 18650 batteries are not discharging cocorrectly? I bought some Samsung 25R and was notified by the seller not to use them as they were from a bad batch that were not discharging correctly after I had already been using them. They seemed to be working just fine, but I stopped using them anyway. But I have a lot of other 18650 batteris that I use for vaping and would like to know what I need to be on the lookout for. Thanks for your time.

Good question. A bad 18650 can burst or damage the electronics using it. Some electronics have overload protection which greatly reduce the likelihood of damage. Your device may have that protection so the battery is protected once by the in battery “protection” (which might be failing) and again by the device. Regardless, if the manufacturer/seller is recommending not using them, I would stick with that. A burst 18650 is a mess. Get them to give you replacements and move on.

im trying to change dead 18650 batteries in a triple drill battery pack they have the code SE US 18650VT but i cant work out which battery i need, i know they are only 1.5 a/hr…(can i upgrade to bigger) 12v drill the other line under that code is.T C112VSG19R. this is the line i cant interperit or find any info on.thanks for any feedback…cheers

It’s probably safest to contact the tool manufacturer directly. If it’s a battery pack (versus individual batteries), they probably have proprietary battery packs and using anything else is likely to void the warranty.

You’re welcome. Sorry I don’t have more specific info, but there are a LOT of different tools out there, and many companies are bundling the 18650s for specific applications, even solar electric systems. If you’re past your warranty period on the tool, are handy, and the company is no help, you could try swapping out the batteries in the pack with well rated 18650s. I just snagged August and he’s going to comment more on this option.

We cant recommend any tinkering… but we have done it successfully on a laptop and a simple battery pack (both out of warranty). The risk is that you will damage electronics or even start a fire. Many of the devices are built in a way that you cannot easily access the battery packs. Also some are be designed for a specific voltage and/or amperage. The fact that tons of devices use 18650’s in series or parallel make them a tempting self repair project. All we can say is stay safe and if you choose to tinker and are successful, please leave a comment so others will know too. There are YouTube DIY rebuild videos for various brands of battery packs. All the best.

I have seen 18650 battery’s advertised with capacities up to 9900 mAh. Are these real? Is that a maximum a 18650 can be in mAh?

The highest current stable 18650 battery is 3500 mAh. I fully expect the research to improve over time. 9900 is not real. Also watch out for batteries without overcharge protection. Check reviews carefully. Best of luck.

After quick research, I believe it is a different form factor of battery. Not an 18650. The “S1 S2 S3 S4 S5” battery, is a brick design for cellphones, specifically a code that matches the form factor for the specific Samsung model. In my mind those are not 18650’s even if they are described as one. They are square or rectangular and thin and unique to a specific device. They use similar technology to an 18650 and fit inside a cellphone, tablet or other thinner portable computing device.

1s, 2s, is gow many cells in series. series connection will increase voltage, parallel will increase capacity. 1s would be 1 cell @3.7v 2s would be 2 cells connected positive to negative (think old flashlight stacking batteries in handle) @ 7.4, 3 s being 3 cell- @ 12.1v and so forth.

hello, I am a dentist and use my led surgical light powered by battery pack of two pack 18650 2200mah, I just replaced my battery pack with a fresh battery pack. question: how can I make my battery pack last longer? use it till it drains and then recharge? or keep it connected to my charger intermittently through out the day as I use is daily. thanks Drlopez

Good question. We added a couple sections in the post to answer this. A quick answer is you want to balance recharges with “using up” the battery. Check your specific battery specifications for lifecycle and charging recommendations. In general though, if you recharge before the battery is at least partly depleted you “lose” a recharge – and batteries only have 300 to 2000 total recharges before they should be replaced. Generally you want the battery to drop from 3.7v to about 3v. In other words don’t top off a 3400mAh battery at 3300mAh instead charge it at 2500mAh or even 2000 (where you choose depends on the number of recharges you expect and the devices sensitivity to low voltage/amperage). I hope this helps.

Hi August. I do not agree with you regarding the charging of batteries. If you look at the datasheets of these batteries, you will see that the lesser the drain on the battery the longer the battery will last. It is the same with cellphone batteries, also Li-ion. My cellphone battery get charged every night. Mostly my battery still have 35% to 45% charge left. I have no problem getting 2-3 years life out of my cellphone battery. Years ago people was told to fully discharge the battery before charging. That might have been correct for old battery types like Nickel Metal Hydrate batteries, but Li-Ion batteries give you the best life performance if you can keep them between 40% to 80% charge. I viewed the datasheet of a 100Ah Li-FePo4 battery pack, used for solar systems, the other day. It is rated at 2000 charge cycles, but they gave a graph showing expected life time at different discharge depths between charges. If you don’t discharge it more than 50% you can get almost 20 years life out of the battery, based on every day recharging via solar.

You are correct. It is why I like larger packs where possible (higher wattage at same voltage to allow lower overall drain). And as you noted, this is recommended by the manufacturers and has to do with the design of the 18650 batteries. I don’t follow all the rules, I leave mine in flashlights and other devices until they don’t light up the way I want. So I am not staying in the 40% to 80% range. I don’t worry about the cycle rates because 2000 is awesome but 500 to 1000 is just great too and I don’t have to monitor them all in detail, but if you do you can drastically extend their life. Thanks for the feedback.

I’m trying to use 18650 in a trail camera as directed by the owners manual. The 18650 I bought are Nurie18650-1A. 3.6 v. 2600mAh, it call for 2 batteries in the camera. How do I know if these are the correct battery ? It mentions something about PR200 when discussing the battery ?

I believe you are asking about the PR200 Trail Camera – it looks like that model requires any two 18650s. Although the Nuon NURE18650 will work, it lists that it is a high self discharge battery (it loses charge just sitting around). Also, the Nuon is only 2600mAh. Instead I recommend a 3000mAh to 3400mAh protected mode low self discharge 18650, such as the: Samsung, Panasonic, Orbtronic, LG or Nitecore. Finally, you need to confirm with the camera manufacturer manual for exact information and battery types.

Hi. What a useful website! I am in the process of changing the Samsung 1500mAh18650 batteries on my AEG vacuum cleaner. it is 5 1/2 years old and they have gone already! (joke). Am I best to replace with the 18650 3500mAh units. Same physical size etc. Also, the manufacturer’s instructions are to leave the cleaner permanently on charge. Is that a good idea? Thanks

High mAh will in general be safe- it will just run longer (more capacity) – the wattage is 3.7v x 1500 = 5500m-watts vs the 3.7v x 3500 = 12,950 m-watts. The “charge all the time” part is more tricky. It depends on the device, electronics and charger. If you get lower self discharge batteries i suspect you would only want to charge it before use (or after its dead). You really need to confirm with the manufacturer to confirm – if they have another small battery in the electronics the trickle charge could be to keep the unit powered. I cant be sure, so use your best judgement.

Hi August, I am one of those species that are naturally inquisitive and will forever “tinker” with everything. the latest being replacing my NiCD batteries in my cordless drill with LI-ion batteries. I have matched the voltage and the drill 18V works fine. I have not yet recharged the batteries.,Can I use my NiCD charger to charge the replaced LI-ion batteries? A friend of mine bought me Rekieta 18650 12000ma/h3.7v batteries from a china shop which I have tried in a similar way on my 14.4v drill, also matching the voltage. Sadly the drill does not work although the voltage is correct. the lettering on these batteries are very foreign and I cannot determine whether they are indeed rechargeable or not. HELP.

August is up to his eyeballs in alligators at work at the moment, so not much time for the site. From what I was able to find online at this QA on Quora “Can I use a NiCad battery charger for lithium?“, the most likely answer seems to be “No. voltage profile, current profile, and current tapering profile are all different.” Batteries can explode or have a meltdown under conditions that they were not designed for, so be careful.

I just received a flashlight that uses a 18650 battery. The flashlight says “shustar”, “Albinaly”, and “CE RoHS” in different places. The battery says “shustar”. The wall charger has a light on the plug-in part that glows yellow when plugged in; don’t know if it changes color when the battery is fully charged because I just started charging the battery. Did I get anything worthwhile? I assume the battery is not a protected type.

The best I can say is track back the manufacturer and try to find the specifications and documentation. I do not know which make/model devices you are using. We recommend the better reviewed, name brand flashlights and chargers. The name brand are a few more dollars but you can call for support and they have wider reviews. Regarding the battery, we recommend that you use a protected mode 18650 regardless of the device unless it specifies an unprotected 18650.

Hello. I have a question that I think will be more common this year with the popularity of outdoor Wi-Fi security cameras, and the solar charging panels to keep the cameras running day night. I have purchased a few of the solar chargers dedicated for Amazon Blink cameras. The Blink cameras run on a pair AA Li-Ion internal batteries, that are advertised to “run for up to two years”. Obviously, replacing the internal pair of AA batteries with a pair of 18650 rechargeable batteries, running from inside a solar panel, to the USB port on the cameras, should do better. The Blink cameras’ Chinese aftermarket dedicated solar panels have two 18650 flat top 3.6V 2600 mAh of various branded batteries mounted in the back of the panels; where there is also a bit of circuitry on a small board. The solar panel specs says it outputs 6.0 V, 0.4 A. I am curious about what type of 18650 batteries will work best in this variable load/trickle charge situation. The cameras are awake full time 24/7, but not recording and/or sending Wi-Fi radio signals much of that time. The battery usage is a situation where there is a tiny draw full time, and larger draw occasionally when they are motion tripped, and also being recharged maybe 12 – 14 hours a day at various levels of solar power. Most of what I’ve seen for the small solar power panels are using lower capacity batteries (2,200 to 2,600 mAh). Aside from price, is that because the charging current from the solar panel is so low (Max 0.4A)? I’m concerned about the the “flat top” battery style (not protected?), supplied in the panels, but I used those for years in E-Vape service. Just lucky? I think the high end chargers used, along with the vape devices’ circuitry maybe provided protection? Well that’s just one concern. The bigger question is what style/type of 18650 will work best (most durable) for the daily variable solar charging, along with simultaneous variable draw from the batteries. I see a plethora of brands, and models out there, and don’t relish frequently changing out batteries whilst balancing on a ladder. Like some other commentators, price has a lower priority/concern than ladder climbing frequency.

The solar panel USB feed is a good idea. To confirm runtime etc I would need specs on the panel. Two 18650s provide up to 25ah where the two AA provide 9ah. So the panels (if they charge even with lower quality batteries should do far better than the internal AAs and last for years. Solar Panel. The wattage (output) of the solar panel and amount of sun it gets is key. If the panel can’t get enough sun the batteries will eventually die. Solar Panel 18650. Nearly all manufacturers use the cheapest battery that will perform in the device. Unprotected are cheaper so they build the “protection” into the electronics instead of the battery. If you replace the unprotected battery with a better protected battery it will likely give you better life but I cannot be sure. If the panel gets enough sun it is probably unnecessary to replace the batteries right away. One way to confirm them is remove them and put them in a protected charger to check their max wattage. Alternate solution. The 6 MinPak waterproof 6×18650 pack could use your old vaping batteries and still have more than 10x the watt hours. If it works, you could just change them out every 3 to 5 years, recharge and replace. This might be a better pick for wooded areas. As I don’t have specs, any “creative solutions” would need to be tested.

Hello August: I have a cordless vacuum (Type AE – 14.4V DC) hat uses 4 batteries LGDAHB31865. I searched and find that this refers to a 18650 BATTERY. I want to replace it for equal or ideally better ones. I live in Canada and I do not find the reference above mentioned anywhere other than China. Could you please help me with some brand name, reference o place where I could buy it. I’m older and the vacuum is like new and been working well for me (light and handy), but the batteries are almost dead after 2 years and the manufacturer offers no help even know it is a big Company. Thanks in advance Jaime R.

Yes the LGDAHB31865 is a High Discharge LG 18650. They appear to be available on eBay. I can’t suggest using any other battery. The risk is that the electronics might be tweaked to match that specific battery (charge/draw). First, idea is to charge the LGDAHB31865 batteries outside the unit to see if they truly are dead (if they dont charge then you know its not your unit). Second idea… I suspect you could use two 2 packs Orbtronic 18650 batteries (I have these). There is a risk that this could damage the vacuum or the new batteries. I suspect the Orbtronic might allow the unit to run longer also. Although I cannot recommend it, if you test it out please keep us posted. Best of Luck Jaime R, sorry I could not provide a definitive answer.

August, thank you for your prompt answer. I’ll check on eBay to see if they have it. The solution of the Orbtronic 18650 batteries, will be more expensive than buying a new vacuum. Nowadays, it is difficult to find and appliance that last more than 2 years.

Yup that is why they use cheap batteries, everything is about cutting unit costs. BatteryJunction.com might have cheaper one unprotected 18650s (which I suspect that your vacuum is using). We buy the expensive batteries and they last much longer. Again be careful, the electronics could smoke if they had a tight match to the battery specs (and remember unprotected 18650s can burst).

August, this is the type of batteries that this machine uses (http://www.cylxpower.com/previewimg.jsp?fileID=ABUIABACGAAgseS5xQUo7rLI8wYw6Ac46Ac); I guess they are unprotected. I did find on eBay from a Canadian seller this (https://www.ebay.ca/itm/2X-18650-9900mAh-Li-ion-Battery-3-7V-Rechargeable-Canadian-seller/333462620310). Do you think that will work? Thanks again for all your help.

Hi Jaime. August is having an extra crazy week at work (they dumped a big project that would normally take months in his lap and want it done this week), so I decided to chime in. For better or worse, the only way to know for sure it to try and see if it works. The odds look good, but you can’t tell for sure until you try.

Please let me be BLUNT! There is no such thing as an 18650 Cell that can deliver over 4000 MAH! NONE Any advert saying that their battery provides this is a Lie False Adverts! and from testing they are usually less than 2400 Mah. Additionally they have a high “internal” resistance, which means that there is a higher voltage drop at higher current levels. My personal guide line would be : Buy Japan or South Korea mfg 18650’s ALL China branded are inferior and/or falsely labeled. Many of the Adverts are just LIES! Amazon and Ebay should stop listing them.

Hi, I just recently started buying LED flashlights powered by 18650’s. I understand the higher mAh batteries give longer runtime, but now I just ordered a “high power” flashlight that says to use “high discharge” rate batteries of 10A or more, so my question is, can you tell if a 18650 cell is “high discharge” just from the numbers/ letters printed on the side of the battery? Thanks, Ed

Some battery types are designed for high discharge, some are “LSD” low self discharge. The high discharge ones generally don’t hold a charge in storage, but do a good job of providing power fast. The low self discharge ones don’t provide power fast but also don’t “leak” power over time. If you have an 18650 battery you will need to research the type of battery to find out if it is normal, low self discharge or high discharge.

Ok, August, so if I understand you correctly, most high discharge batteries will say on the casing “High discharge” or similar- These are the batteries I got; https://edisonbright.myshopify.com/collections/batteries/products/3-pack-edisonbright-ebr34-3400mah-18650-rechargeable-li-ion-protected-batteries. and I am ordering this flashlight; https://lumintoplighting.com/lumintop-gt-mini-pro-3500-lumens-xhp502-led-high-intensity-outdoor-flashlight-p0068.html. which is 3500 lumens- I don’t want to smoke the battery…. Seem like they might work? Thanks, Ed

Ed, It would be best to check with the people selling that specific flashlight. We haven’t used that particular product before, and they should know the items they’re selling.

There are far too many general statements here. The author states his opinion of the best batteries and flashlights. Some of my flashlights are definitely better to use unprotected cells for the same reason some of my vape devices do. The protection circuits are sometimes built into the lights now, and protected batteries will not allow the amp draw needed because they are capped at 10 to 12 amps. Also the best light is often based on the intended use…do you need a long throw, more flood, or combination. Some lights now even have proprietary batteries and chargers. That is the case with Olight Seeker 2, but you can actually use an externally charged 21700 orbtronics protected battery with the buttontop closest to the cap. You can’t however charge that battery in the light. The Olight special modified battery re-routs a negative contact to the positive side for the magnetic charging. The negative terminal on the light is at the head.

Hi August, Is it safe for 18650 batteries to be “plugged in” all the time, for example in applications like emergency back up lights, where they come on only during power outages? Regards, Paul

August is up to his eyeballs at work, so I’ll chime in. While it might not be ideal from a battery life perspective, if that’s what the device requires to function, that’s what it requires to function. It should not be safety concern (no risk of explosion, etc).

I’m buying a protected 18650 battery for a solar charging light in my garage. I only need one, but the SH is the same as the price of one battery. If I order 2 or 3 and don’t need them for 2-4 years, will they still be good or am I better off just buying the one now and deal with it.

After doing some digging, it looks like most people are not having any issues with 18650 batteries that have been stored a few years. The article “Proper 18650 Battery Storage” suggests a charge of roughly 40% for best storage life.

The Best 26650 Lithium Ion Battery

IFR26650-E3400 3400mAh High Cost-Effective LiFePO4 Battery Long Cycle Life, Large Capacity, High Cost-Effective Nominal voltage:3.2V Rated capacity:3400mAh Maximum continuous charging current:3.4A (1C) Maximum continuous discharging current:10.2A (3C)

IFR26650-G2W 3350mAh Low Temperature LiFePO4 Battery Low Temperature Charging and Discharging with High Capacity Retention Ratio Nominal voltage:3.2V Rated capacity:3350mAh Charging temperature:-20~60℃ Discharging temperature:-40~60℃

IFR26650-G3 4000mAh Large Capacity LiFePO4 Battery Large Capacity, High Energy Density, Nice Safety Nominal voltage:3.2V Rated capacity:4000mAh Maximum continuous charging current:4.0A (1C) Maximum continuous discharging current:12A (3C)

IFR26650-G4 38000Ah Large Capacity Lithium Ion Battery Large Capacity, High Energy Density, Nice Safety Nominal voltage:3.2V Rated capacity:3800mAh Maximum continuous charging current:3.8A (1C) Maximum continuous discharging current:11.4A (3C)

IFR26650-P2800mAh Power Type LiFePO4 Battery 15C High Rate Discharge, Fast Charge Nominal voltage:3.2V Rated capacity:2800mAh Maximum continuous charging current:14A (5C) Maximum continuous discharging current:42A (15C)

26650 Low Temperature Lithium Ion Battery Good low temperature performance Charging temperature:0℃ ~ 45℃ Discharging temperature:-40℃ ~ 60℃ Application field: special equipment, special industry, polar science exploration, frigid zone emergency, etc.

26650 Energy Storage Lithium Ion Battery Large capacity Emergency energy storage lithium ion battery Large voltage, large capacity, long cycle life Solar energy storage, special portable power supply, emergency backup power

26650 Power Lithium Ion Battery Large capacity and large power High energy density Long cycle life Good safety performance

26650 LiFePO4 Battery Large Capacity Nice hot stability Advanced safety Outstanding high rate discharge performance

650 Lithium Ion Battery

1.26650 Lithium Ion Battery Definition

26650 is a cylindrical lithium battery specification. 26650 battery is applicable to special equipment, medical equipment, instruments, power tools, logistics, security monitoring, exploration and mapping, etc.

26650 lithium battery dimension: The diameter is 26mm, and length is 65mm.

2.26650 Lithium Ion Battery Advantages

26650 lithium battery has high energy density, low self-discharge rate, stable charging and discharging performance, no memory effect, no decomposition in heat, high safety performance, long life cycle and high voltage. You can connect 26650 lithium battery in series or in parallel. It is environmental friendly and has no pollution.

3.Single 26650 Lithium Ion Battery Cell

26650 lithium battery materials are mainly divided into ternary materials and lithium iron phosphate materials.

  • Voltage INR26650 lithium battery has nominal voltage of 3.6V, full charge voltage of 4.2V, and discharge cut-off voltage of 3.0V. IFR26650 lithium battery has nominal voltage of 3.2V, full charge voltage of 3.65V, and discharge cut-off voltage of 2.0V.
  • Capacity IFR26650 lithium battery capacity includes 2800mAh, 3000mAh, 3200mAh, 3400mAh, 3600mAh, 3800mAh and 4000mAh. INR26650 lithium battery capacity tends to be 4500mAh, 5000mAh, 5500mAh and 6000mAh.

650 Lithium Ion Battery Positive Electrode Materials

26650 lithium battery positive electrode materials include lithium cobalt oxides, lithium manganese, NCA, NCM and lithium iron phosphate. Material system determines the working voltage and single cell capacity. Various materials manufacturers and cell manufacturers improve the overall indexes, such as battery voltage and capacity, by special material adding, coating process and manufacturing process improvement. Working voltage and theoretical capacity of various materials are normally as follow:

  • Lithium cobalt oxides 3.6V, theoretical capacity 274mAh/g
  • Lithium manganese 3.7V, theoretical capacity 148mAh/g
  • Ternary material 3.65V, theoretical capacity 278mAh/g
  • Lithium iron phosphate 3.2V, theoretical capacity 170mAh/g
  • The materials determine the cycle life of the battery, so does the manufacturing level of the battery manufacturer.

26650 LiFePO4 Battery Advantages

  • High energy density: theoretical specific capacity 170mAh/g, actual specific capacity ≥140 mAh/g (0.2c, 25°C);
  • High safety: the most secure positive electrode material for lithium ion batteries;
  • No pollution: does not contain any heavy metal elements that are harmful to human body;
  • Long cycle life: it can charge and discharge more than 2000 times under 100%DOD;
  • Fast charging performance: Lithium iron phosphate battery can be charged at high rate.
Tap Density(g/cm3) 2.8~3.0 2.0~2.3 2.2~2.4 1.0~1.4
Gram Volume (mAh/g) 135~140 140~180 90~100 130~140
(V)Voltage Platform 3.7 3.6 3.7 3.2
Cycle Performance ≥500Times ≥500Times ≥300Times ≥2000Times
Safety Performance Bad Good Very Good Advanced
Applications Medium And Small Size Battery Small Battery/Small Power Battery Power Battery, Low Cost Battery Power Battery/Super Large Capacity Power Supply

650 VS 26650

Compared with traditional 18650 battery, 26650 lithium battery has a larger capacity in the same material system, and has 52 percent fewer cells than that of 18650 battery. This means that the complexity of the battery management system, the number of metal structures, the volume of the battery, and the cost of the battery system can be significantly reduced for a power battery with the same capacity.

What is the difference between 18650 lithium battery and 26650 lithium battery?

  • Different rated capacity: IFR26650 lithium battery rated capacity is 3000-5000mah, while IFR18650 lithium battery rated capacity is 2200~3200mAh.
  • Different dimensions: the IFR26650 has a diameter of 26mm and the IFR18650 has a diameter of 18mm.
  • Different reference mass: the production mass of IFR26650 lithium battery is 94 grams, while the production mass of IFR18650 lithium battery is 45 grams.
  • Different battery capacities: With the same battery material, the 26650battery capacity is larger than that of 18650. It is assumed that the 26650 battery with ternary material is generally around 5200mAh, while the capacity of 18650 battery is mostly around 2600mAh.
  • Different application environments; 18650 lithium battery is applied as illuminator battery, industrial supporting lithium battery pack, electric tool battery and electric bicycle battery, which are mostly power lithium battery, while 26650 lithium battery is applied in energy storage base station and solar energy storage.
  • Different endurance: 26650 battery have a larger volume ratio than 18650 battery, so it has a larger space filling material to achieve a larger capacity. At present, the capacity of 18650 battery has 2200mAh, 2600mAh, 3100mAh, etc., while the capacity of 26650 can achieve 4000mAh, 4200mAh, 4500mAh, and the endurance time will be longer.

650 Lithium Ion Battery Safety Test

1、Over Charge

After standard battery charging, measure the initial state of the battery. When the battery is in normal state, charge the battery with 3C current to 10.0V, and then charge the battery at constant voltage until the current reaches 0.01c. Observe the appearance change of the battery.

Result: No fire, no explosion.

2、Over Discharge

After standard battery charging, measure the initial state of the battery. When the battery is in normal state, discharge it at 0.5C to 0V. Observe the battery appearance change.

Result: No fire, no explosion.

3、External Short Circuit

After standard battery charging, measure the initial state of the battery. Put battery in an explosion-proof cover and make it a direct short circuit in its positive and negative electrodes (circuit resistance is no more than 50 m Ω), when the battery temperature is down to about 10 ℃ lower than the peak temperature, the experiment is over. Observe the temperature and appearance of the battery.

Result: No fire, no explosion.

4、Heater Test

Measure the initial state of the battery. After standard battery charging, put the battery in the heater. The temperature rises to 130±2℃ /min at the rate of (5±2℃) /min, and keep the temperature for 30min. Observe the battery appearance change.

Result: No fire, no explosion.

5、Drop Test

Test the initial capacity of the battery. After standard charging, measure the initial state of the battery. Drop the test battery vertically and horizontally onto the cement floor freely from a height of 1m (the lowest height).

Result: No fire, no explosion.

6、Impact Test

Put a steel rod with a diameter of 15.8mm in the middle of the fully charged battery, then a 10Kg hammer was free-falling from a height of 1.0m to the upper part of the battery.

Result: No fire, no explosion.

7、Extrusion Test

Put the battery cell between two extrusion surfaces of the extrusion equipment. The cylindrical battery cell axis is parallel to the extrusion surface. Increase the pressure gradually to 13kN, and maintain the pressure for 1min.

Result: No fire, no explosion.

650 Lithium Ion Battery Charging

1.26650 Lithium Ion Battery Charging Precautions

  • The basic requirements for charging 26650 lithium battery are specific charging voltage and charging current at each stage. Some auxiliary functions are added to prolong the battery life.
  • In order to ensure the stable and reliable operation of the battery and prevent the interference of transient voltage change, the time delay circuit with over-charge, over-discharge and over-current protection should be designed to prevent the instability caused by transient interference.
  • The factors affecting the safety and effective charging of 26650 lithium battery include voltage, current and temperature. Therefore, these three factors should be taken care of and controlled in the charger design.

2.Can the 18650 battery charger charge 26650 battery?

You can use the charger of 18650 lithium battery to charge the 26650 lithium battery, but do not use it for a long time. Because the charger of 18650 lithium battery has a relatively high voltage platform, the voltage platform of 18650 lithium battery is 3.6V and 4.2V, and the voltage platform of 26650 lithium battery is 3.2V and 3.6V. Therefore, long-term use will cause damage to 26650 lithium batteries.

How do you choose 26650 lithium battery?

26650 lithium battery is widely used in power tools, lighting, wind power energy storage, photovoltaic energy storage, electric vehicles, toys, instruments, UPS backup power, communications equipment, medical equipment and special lights. What do we pay attention to when purchasing 26650 lithium battery?

1.Appearance and Production Process

Appearance refers to the appearance, workmanship, size and process of 26650 lithium battery. After polishing, the rubber oil polishing materials feel good. At the same time, the insulation performance is better.

2、Capacity Label

A 26650 lithium ion battery without a clearly capacity label is likely to be a garbage battery that uses an inferior battery cell or is reassembled with a recycled battery cell. There are many cheap 26650 lithium batteries on the market, which are made of recycled or disassembled battery cells. Although they are cheap, they have short life and unstable quality. Careless use may damage the equipment or even cause an explosion.

3、Protected or Unprotected

The characteristics of 26650 lithium battery determine that 26650 lithium battery need to be equipped with a protective board to prevent the occurrence of overcharge, over-discharge and short circuit. The 26650 lithium battery without a protective board will be in danger of deformation, leakage and explosion. Amid fierce price competition, battery package factories have sought cheaper protective circuits or omitted them altogether, which may make the market be flooded with 26650 lithium-ion batteries that could explode.

4、Flat or Button Top

  • There are flat top and button top 26650 lithium batteries. The difference between them is that one has a protection board, while the other has no protection board.
  • Flat top 26650 lithium battery: no protection board
  • Button top 26650 lithium battery: It has protection board, because the top of the protection board protrudes. The protruding part is the protection board.
  • In general, I recommend purchasing a button top battery to ensure that it is compatible with a wide range of devices and usages. The positive and negative electrodes of electrical appliances are designed with springs, so that it is retractable, and both button and flat top batteries can be used.
  • But when a flat top battery is connected in series, the positive electrode of the flat top battery cannot touch the negative electrode of the other battery.

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