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Buyers Guide: The Best 18650 Batteries Of 2021

3500 mah batteries



There is a lot to love about 18650 batteries, but there is also a lot to learn if you want the best 18650 battery available for your device.

 Below we will list some of the most frequent questions we get about 18650 batteries, as well as some information on the most popular batteries we carry in-store.

Common Questions About 18650 Batteries

We have listed some helpful FAQ’s below for customers who need some help selecting a battery. As always, feel free to contact us if you cannot find the answer to the question(s) you have in mind, we are happy to help!

What is an 18650 Battery?

18650 batteries are lithium-ion batteries that get their name from their external measurements. Most 18650 cells are roughly 18mm in diameter and 65mm in length. 18650 batteries are one of the most common cells in the flashlight industry.

High power outputs, impressive runtimes, and long lifespans make them ideal for modern high-performance torches. Most lithium batteries have a lifespan of 2-3 years or 300-500 charge cycles, whichever comes first. Of course, as you might assume the higher the quality of the battery you choose, the longer its lifespan.

Which 18650 Battery Is The Best For Me?

The best 18650 battery for you is going to be one that is (a), the correct size for your flashlight or the other device you are using and (b), one that comes from a reputable brand.

 Why? Brand names are important because cheap knock-off 18650 batteries perform much lower than their advertised outputs and most of all, you want to operate your light safely and you want it to be reliable. Rest assured, all the batteries we carry in-store are tested and proven performers!

Sizing, on the other hand, is something you will need to confirm in your user manual or through the manufacturer. Not all 18650’s are created equally, and you want to make sure you select the right one. As you will read below, 18650 cells can be flat top or button top. They can also be protected or unprotected. This information impacts the size of your battery, so you need to know which one you need in order to select one that will be compatible with your light.

Regarding this, keep in mind that most manufacturers also make recommendations in the datasheet or the user manual of your light regarding the battery(ies) to use with the device. The batteries listed on these documents are always our first recommendation, since the light has been tested with these cells. 

Key points you need to know!

18650 batteries can be flat or button top. What does that mean?

Flat top batteries are flat on both ends, and button top batteries are flat on one end and there is a little button top (nip) on the other side that makes them a little bit longer in size. Some flashlights do not have enough space inside of them to fit button tops batteries and will simply require using flat tops batteries as a result, and vice-versa.

18650 batteries can be protected or unprotected. What does that mean and what you need to know?

Protected batteries are much safer to use in your devices. Protected lithium batteries have an electronic circuit in them that protects them from overcharge, over discharge, dangers caused by temperature, over current and short circuit problems. Unprotected cells do not have this built-in circuit in them, so they are vulnerable to these safety hazards. You must also know that protected batteries are a bit longer than unprotected cells, because of that added protection. For this reason, protected and button top batteries are the longest 18650’s and unprotected and flat top cells are the smallest.

You will find that most flat top batteries are unprotected, even though a few of them will be protected. Here at Flashlight World, you will not find protected flat top batteries in our store because they are simply not a battery, we use often in the flashlight industry.

 All of the flat top batteries we sell are unprotected. We do, however, carry both unprotected and protected button top batteries, depending on the length and performance you are looking for and that will best suit your device.

 At this point, you might be wondering: What are the advantages of choosing an unprotected battery? Unprotected batteries often have more current capability and more capacity, meaning that they will often run for a longer period between charges. They are also much less expensive than protected cells.

Do I Need A Li-Ion or n IMR 18650 Battery?

IMR cells are batteries with a slightly different chemical composition than traditional lithium-ion batteries. They utilize lithium-manganese rather than lithium-cobalt, making them less prone to damage or failure when used correctly. IMR batteries also charge faster and discharge at higher currents.

Disadvantages of using IMR cells? IMR batteries have lower capacities compared to standard Li-Ion cells, which means they will not run for as long between charges. It is also important to know that IMR batteries can require more monitoring during use. Allowing an IMR battery to drain below +/- 3.0 volts will often result in damage. These batteries are typically unprotected, whereas standard Li-Ion batteries often include the protections described above.

Either way, it would be wrong to think that IMR batteries do not perform as well as standard Li-on cells, they are both very good batteries. A higher mAh is not the only thing that defines a good battery, which is often what attracts us to standard Li-on cells in the first place. 

Remember, if you are unsure of what battery you should use, please refer to the user’s manual of your device. You can find most of them online these days, or you can consult the manufacturer for more details. 

Can I Use A 21700 Battery Instead Of An 18650?

18650’s and 21700 batteries are NOT the same size and have completely different internals. Please refer to the user’s manual of your device for more details on what battery(ies) you should use with the product you have in hand. For your safety, no battery that is not specifically recommended in the user’s manual should be used with your device. If both types can be used, it will be mentioned in your user’s manual.

Running inappropriate cells in your device could not only damage the light and the battery(ies), but this will void your warranty, if there is one, and could possibly cause fire or an explosion.  

Our Picks For Best 18650 Batteries Of 2021

Here is the list of our best-selling and top performers so far this year. Have no doubt, somewhere in the list below, the best 18650 battery available for your device is waiting.

Panasonic NCR18650B

The Panasonic NCR18650B is one of the best 18650 batteries in our store, and a customer favorite by far. Both versions get rave reviews from our customers, but make sure you select the right type for your device.

Flat-Top Unprotected: The unprotected flat-top version of the NCR is a popular battery for both flashlight manufacturers and customers alike, who give it high marks for its impressive power delivery and above-average runtimes. If you need a flat-top 18650, you cannot go wrong with a high-quality brand like Panasonic.

 

Capacity

3400mAh

Voltage

3.6V

Current

4.8A

Warranty

N/A

Protected

No, Unprotected

Battery Type

Flat top

  

Button-Top Protected: The button-top version of the Panasonic NCR is another popular choice for flashlights without internal protections. Panasonic’s safety testing is known for its quality and consistency, so their PCB protection rating is one you can trust.

 

Capacity

3350mAh

Voltage

3.6V

Current

4.8A

Warranty

N/A

Protected

Yes

Battery Type

Button top

 

Fenix ARB-L18 Series

The ARB-L18 series is a premium line of batteries from the flashlight gurus at Fenix. These are a popular choice for customers willing to spend the money to have the best 18650 batteries available. These batteries are more expensive but have the highest performance and best safety features.

ARB-L18-3500: The 3500 is the best-selling Fenix battery in our store, thanks to its 3500mAh capacity and impressive safety features. With 3.6V of power, up to 500 charge cycles per battery, and a long list of fail-safes including three-way over-heating protection, pressure-release vents, and a collision and impact-proof steel shell make this battery the longest-lasting, highest-performing cell in this series.

 

Capacity

3500mAh

Voltage

3.6V

Current

5A

Warranty

12 months

Protected

Yes

Battery Type

Button top

 

ARB-L18-3400: The 3400 shares its premium construction and safety features with the 3500 but has a slightly lower capacity at 3400mAh. The 3400 is also a few bucks less than the 3500, so this may be the best 18650 battery for you if you do not need the extra runtime.

 

Capacity

3400mAh

Voltage

3.6V

Current

5A

Warranty

12 months

Protected

Yes

Battery Type

Button top

 

ARB-L18-2900L: The 2900L is a cold-resistant cell. You’ll give up a little capacity in exchange for the batteries’ impressive -40-degree Celsius performance, but that’s a welcome compromise for customers working in freezing conditions.

 

Capacity

2900mAh

Voltage

3.6V

Current

4A

Warranty

12 months

Protected

Yes

Battery Type

Button Top

 

ARB-L18-3500U & 2600U: The 3500U (3500mAh capacity) and 2600U (2600mAh capacity) are the integrated USB-charging versions of the L18 series. That’s right, there’s a USB port directly on these batteries so all you need to charge them is a USB cable that you will plug directly into the batteries.

Integrated USB charging is convenient to use in flashlights that do not have their own internal USB charging system (no USB port on the flashlight itself) because you do not need to buy a separate charger for them. Please note that these batteries can be recharged using either the USB port or a standalone charger like the Fenix ARE-A2 or ARE-D2, BUT attempting to use an integrated USB-charging battery in a device that already has an internal USB system is not recommended and can cause damage; the double USB (device USB port + battery USB port) seems to cause problems.

 

Capacity

3500mAh / 2600mAh

Voltage

3.6V

Current

3A

Warranty

12 months

Protected

Yes

Battery Type

Button Top

 

Nitecore NL Series

Nitecore’s NL series is a premium line of high-tech, high-performance batteries. Owners of Nitecore flashlights prefer the NL series as OEM replacements for many of their torches, but these top-of-the-line batteries will work in many other 18650 applications as well.

Nitecore NL1829 Cold Resistant: Nitecore’s 1829 series comes in two flavors: The standard rechargeable, and the USB-rechargeable version. Regardless of which type you need, both batteries feature 3.6V power, a reliable 2900mAh capacity, and guarantee performance in temperatures as low as -40 degrees Celsius.

 

Capacity

2900mAh

Voltage

3.6V

Current

4A / 5A for USB

Warranty

12 months

Protected

Yes

Battery Type

Button top

 

Nitecore NL1834: The 1834 is our most popular battery from Nitecore, thanks to its 3.7V power and long-lasting 3400mAh capacity. This button-top battery is fully protected against over and under voltage and runs for up to 500 recharge cycles.

 

Capacity

3400mAh

Voltage

3.7V

Current

 4A

Warranty

12 months

Protected

Yes

Battery Type

Button top

 

Nitecore NL1832: The 1832 is another customer favorite from Nitecore. It shares the same 3.7V power and high-quality protection as the 1834, with a slightly lower capacity of 3200mAh.

 

Capacity

3200mAh

Voltage

3.7V

Current

4A

Warranty

12 months

Protected

Yes

Battery Type

Button top

 

Samsung 18650 INR Series

Looking for an 18650 battery but you don’t want to break the bank? These Samsung batteries are for you.

Samsung INR18650-25R: The 25R has a reputation among battery enthusiasts for its high-current capacity and legendary stability. 3.6V of power, 20A max current, and a respectable 2500mAh capacity make this one of the most well-rounded packages for your money in our store.

 

Capacity

2500mAh

Voltage

3.6V

Current

20A

Warranty

N/A

Protected

No, Unprotected

Battery Type

Flat top

 

Samsung INR18650-30Q: A higher-capacity alternative to the 25R is the Samsung’s 30Q flat top battery. This is another great long-standing and low price-point battery with 3000mAh capacity and low internal resistance.

 

Capacity

3000mAh

Voltage

3.6V

Current

15A

Warranty

N/A

Protected

No, Unprotected

Battery Type

Flat top

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