21700 Vs 18650: Behind the Lithium-Ion Battery Cell Battles. 18650 battery 4000mah

This is a money-saving 4-pack of high-capacity ICR 18650 3.7V 2600mAh rechargeable Lithium batteries.

These batteries are perfect for solar science fair projects involving solar cells and panels. Also great for building an off-grid solar power system for camping, RVs, household appliances, doorbell cameras, etc.

Multiples can be hooked together in series to get higher voltage or in parallel to achieve higher capacity.

Use it in any device that requires a standard 18650 Lithium battery cell.

Specifications:

• 4 x ICR 18650 Lithium-ion batteries
• Button Top
• Voltage: 3.7V
• Rechargeable
• Capacity: 2600mAh (2.6Ah)
• Power: 9.62 Wh
• Material: Li-ion
• Each battery size: 67 mm (2.63 inch) long, 18 mm (0.71 inch) diameter

NO RETURNS POLICY ON BATTERIES:

At our online store, we prioritize providing our customers with brand new and high-quality rechargeable lithium batteries. Due to the nature of batteries, we do not accept returns on these batteries as we cannot verify their usage or condition after purchase. By only selling new batteries, we are able to offer competitive pricing and ensure that all of our customers receive only the best products. Thank you for choosing us for your rechargeable battery needs.

NO RETURNS: Due to the nature of this product and to protect our staff and customers we do not accept returns on this product. You will not be allowed to return this product.

Customer Reviews

Reinhold Schlieper from Palm Coast, Florida Replaced the old battery and got several days more of light in the flashlight used every day for an hour while jogging. I’m impressed.

4-Pack of ICR 18650 Blue Lithium-Ion Rechargeable Batteries. 3.7V 2600mAh Michael from Canon City, Co. USA Excellent purchase. 2nd time I ordered these. Works great.

Delivered quickly Liz from Henderson Being used to Amazon, I was so pleased with how quickly these specialty batteries came.

Great batteries Amanda M Michael from Des moines I bought these for my night owl camera because nightowls only come in 2s. This is the best bang for your buck.

Jonny from Arizona Very good product for the money

They work perfectly! Meridith Lynne Croucher from USA, NY, Newark Came quickly. I had ordered them correctly and they keep our security system running fine!

Jonny from Arizona Great product

Debbie Morgan from Florida My husband was thrilled I found the batteries he needed!! They last an extra-long time and he doesn’t worry about replacing them during the day!! Excellent product!!

1.29 3 x 18650 Lithium Cell Battery Holder. 11.1V 4.99 ICR 18650 Blue Lithium-Ion Rechargeable Battery. 3.7V 2600mAh 4.95 ICR 18650 Green Flat-Top Lithium-Ion Cell Rechargeable Battery. 3.7V 2600mAh 2.59 3.7V Lithium Battery Indicator Tester 1.09 18650 Lithium Cell 3.7V Battery Holder with Leads

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700 vs 18650: Behind the Lithium-Ion Battery Cell Battles

Around here, we primarily FOCUS on the tools and gear surrounding the construction industry. That makes the 21700 vs 18650 lithium-ion battery cell conversations incredibly relevant to us. After all, these lithium-ion power sources reach far beyond the latest cordless tools. They’re driving innovation in Teslas, hoverboards, the vaping community, and so much more.

700 vs 18650: What do the Numbers Mean?

21700, 18650, 20700 and others simply refer to the physical size of the lithium-ion cell. For 18650, it’s an 18 mm diameter x 65 mm length. 21700 is 21 mm x 70 mm. While the explanation is simple, the difference is profound. It’s easy to see with a quick volume calculation.

3.14(9 x 9)(65) = 16,532 cubic mm

3.14(10.5 x 10.5)(70) = 24,233 cubic mm

An extra 5 mm of length and 3 mm of diameter gives us 47% more volume. That’s a little more than 7,700 cubic mm of space to pack with energy-delivering anode, cathode, and electrolyte material.

Capacity = Runtime

The most obvious benefit of going with 21700 vs 18650 is that the extra density means there’s more available energy in them to run your tools and gear longer. Batteries that we see using 18650 cells for power tools range from 1.5Ah (1500mAh) to 3.0Ah (3000mAh) in each cell. 18650 cells on the higher end of that scale have reported issues and 2.5Ah (2500 mAh) cells seem to be where most manufacturers settle at the top.

On the other hand, 21700 cells start around 3.0Ah (3000mAh) and go up to 4.0Ah (4000mAh) for power tool batteries. It’s why we see compact (1P) packs that have 3Ah or 4Ah designations all the way up to 12Ah (3P) big boys.

From the perspective of comparing 21700 vs 18650 in power tools, you’re looking at a 50%–100% runtime gain over today’s standard 18650 packs. Outside the power tool industry, some of these cells reach 5.0 Ah (5000mAh).

18650 Li-ion Battery Cells

• Compact 1P Battery: 2.0Ah–3.0Ah (36 Wh–54 Wh)
• General Purpose 2P Battery: 4.0Ah–6.0Ah (72 Wh to 108 Wh)
• High Capacity 3P Battery: 9.0Ah (162Wh)

21700 Li-ion Battery Cells

• Compact 1P Battery: 3.0Ah–4.0Ah (54 Wh–72Wh)
• General Purpose 2P Battery: 6.0Ah–8.0Ah (108 Wh–144 Wh)
• High Capacity 3P Battery: 9Ah–12Ah (162 Wh–216 Wh)

700 Cells Provide Power

Batteries like the Bosch Core18V, Milwaukee M18 High Output, and Metabo LiHD packs do more than just take advantage of longer runtime. They improve their packs’ cooling abilities and build them with better materials that reduce resistance (ohms). The result is a battery with much greater power available.

Take Bosch, for example. Their standard 18V batteries can produce up to 800 watts of power output. When they upgraded to Core18V, it went up to 1440 watts—an 80% power increase! Other brands report significant power gains as well.

It gives them the ability to produce cordless tools that we didn’t think we’d ever see without a cord just a few years ago. And many of them are outperforming their corded counterparts now.

Power tools are hardly the end product. Outdoor power equipment for lawn care and landscaping, battery-powered inverters, and battery-powered construction equipment are all starting to have cordless options thanks to 21700 lithium-ion battery cells.

Do battery expire? The Ultimate EBL Battery Expiration Guide

Batteries play a vital role in powering our lives. We need them to keep our devices buzzing, fuel our remote-controlled adventures, and more. However, even these little energy powerhouses have their limits, and that’s where battery expiration comes into the picture. This guide will illuminate the mysteries surrounding battery expiration in EBL batteries, address common concerns and anxieties, and provide practical solutions to navigate this phenomenon.

EBL Battery Expiration. What You Need to Know

The world of batteries is evolving rapidly; therefore, understanding their expiration is essential. Doing so will allow you to gain the optimal device experience, thanks to the powerful batteries in their prime state.

So, let’s dive into the expiration details of EBL batteries and discover how to make the most of their power.

Shelf Life of EBL Batteries:

The shelf life of EBL batteries refers to the period during which they can be stored without significant power loss. EBL batteries typically have a shelf life of several years (10 or more, to be precise), ensuring you have reliable power when needed most. It’s essential to check the manufacturing date and adhere to recommended storage conditions to maximize shelf life.

Expiration Dates:

While EBL batteries do not have explicit expiration dates printed on them, they have recommended usage times based on their chemistry and capacity. It’s generally advised to replace batteries after several years or when you think the self-discharge rate has increased.

Keep track of when you purchased your batteries and consider replacing them if they have been used for an extended period.

Capacity Fade:

Over the years, EBL batteries may experience capacity fade, meaning their ability to hold a charge gradually diminishes. this happens with all batteries, no matter the brand.

This can result in reduced usage times and the need for more frequent recharging or battery replacements. Monitoring the performance of your EBL batteries and being aware of any significant drops in capacity can help you stay prepared.

Proper Storage:

To prolong EBL batteries’ lifespan, storing them in appropriate conditions is crucial. Keep them in a cool, dry place, away from direct sunlight and extreme temperatures. Avoid storing them near sources of heat or moisture, as these factors can accelerate capacity fade and shorten their overall lifespan.

Battery Recycling:

When it’s time to retire your EBL batteries, it’s important to dispose of them responsibly. Battery recycling is an environmentally friendly option that allows for the recovery of valuable materials and prevents harmful substances from entering landfills. Check local recycling centers or collection points to ensure your used EBL batteries are recycled properly.

Compatibility Considerations:

EBL batteries come in various chemistries, voltages, and capacities to meet the diverse needs of different devices. It’s important to ensure compatibility between the battery and the device you’re using. Always refer to the device’s specifications and recommended battery types to maximize performance and safety.

When you know a thing or two about battery expiration, you can implement proper storage and disposal practices, and make the most of your battery power. resulting in a greener environment.

Remember to keep track of usage time, monitor capacity fade, and recycle your used EBL batteries responsibly for a seamless power experience.

Shelf Life of EBL Batteries: Power that Lasts for Years

When it comes to shelf life, EBL batteries are designed to go the distance. These reliable power sources offer an impressive shelf life, ensuring you have dependable energy whenever you need it. Let’s explore the shelf life of EBL batteries and how they maintain their power over time.

EBL takes pride in its AA and AAA alkaline batteries, which boast an amazing 10-year shelf life.

With this extended shelf life, you can confidently stock up on EBL batteries, knowing they will retain their power for a significant period.

One of the secrets behind the impressive shelf life of EBL batteries lies in their embedded seal structure. This innovative design expands the space within the crystal lattice, creating more room for hydrogen.

As a result, EBL batteries can maintain a remarkable 75% of their power even after three years of storage. This is made possible through EBL’s dedication to low self-discharge technology, which minimizes power loss during idle periods.

The concentration on low self-discharge is a vital aspect of EBL batteries. By carefully managing the internal chemistry, EBL ensures that its batteries hold their charge over extended periods of non-use. This feature is precious for devices that are infrequently used or in situations where batteries may be stored for extended periods.

The 10-year shelf life of EBL batteries provides convenience and peace of mind. Whether you’re stocking up for emergencies, everyday use, or special occasions, you can trust that EBL batteries will deliver reliable power, even after years of storage.

So, next time you reach for an EBL battery, remember that their embedded seal structure and low self-discharge technology work hand in hand to provide long-lasting power. With EBL, you can confidently rely on their batteries to keep your devices running smoothly, even if they’ve been sitting on the shelf for years.

Everything You Need to Know About EBL Batteries Self Discharge Rates

Self-discharge is an inherent characteristic of batteries and can vary depending on the chemistry and quality of the battery. EBL batteries are available in various types and sizes, including Lithium-ion, Ni-MH, Ni-Cd, and Alkaline. Let’s discuss the self-discharge rate and factors that affect the expiration of these EBL batteries.

How long does it take for lithium-ion batteries to expire?

When it comes to self-discharge rates, Lithium-ion batteries reign supreme, radiating brilliance. These batteries experience a minimal decline of just 1-2% in charge per month. Thus, even during extended periods of inactivity, we can rely on their unwavering power reserves.

How long does it take for Ni-MH Batteries batteries to expire?

Now, let’s turn our attention to Ni-MH batteries, which have a slightly higher self-discharge rate than Lithium-ion ones. In the first 24 hours of rest, they may lose around 10-15% of their charge.

After that, the decline slows to about 1-2% daily. Regular recharging is essential to optimize their performance.

How long does it take for Ni-CD Batteries batteries to expire?

For those utilizing Ni-Cd batteries, it’s important to note their propensity for higher self-discharge. Within the first 24 hours of inactivity, they can lose approximately 20% of their charge. Surprisingly, this downward trend continues at a rate of 10-20% per month. Proper handling, storage, and timely recharging are critical for their optimal utilization.

How long does it take for Alkaline Batteries batteries to expire?

They possess an incredibly low self-discharge rate. Would you believe they retain up to 90% of their charge even after a year of storage? It’s true! With a shelf life of 7 to 10 years, they are our unwavering allies, providing consistent power when needed.

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

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.

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.

It makes a HUGE difference when you share our articles. Thank you so much!

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.

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.

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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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.