What does 18650 mean on a battery?

The 18650 battery seems confusing to many people. But, there is nothing as such that should confuse people while buying batteries. Traditionally the “18650” on the batteries only tell you the size of the battery. It refers to a cell that's 18mm x 65mm in size and mainly it’s exclusive to the size of the lithium-ion?battery?cell, but there is always the chance of having minor variations. Now, the 18650 has become the new gold standard for replaceable and rechargeable batteries in the market.

Are you also worried about what 18650 batteries are and what you should get for yourself? No worries, here is the detailed guide of the 18650 battery to help you save from the fake ones. 

What is a 18650 battery? 

The 18650 battery is basically a type of rechargeable lithium-ion battery. Definitely, lithium-ion batteries have revolutionized portable devices. But, 18650 inherited its name because of the size 18mm x 65mm. They offer the performance of a lithium-ion cell with a capacity in the range of 1800mAh to around 3500mAh and gives an output of about 3.7volts.

You can use the 18650 battery in various devices like laptops, laser pointers, and camera accessories like gimbals and sliders. The 18650 battery can be used in place of any consumer-grade rechargeable battery. Moreover, these types of batteries are not susceptible to damage from charging before being fully discharged as it used to happen with the old nickel-cadmium cells. 

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The 18650 batteries are used in Flashlights, electronics, laptops, vaping (smoking) devices, and even some electric vehicles like Tesla. Make sure that you pick the right battery for you because the wrong choice will make the cells hot. The heat will damage the battery and will reduce its overall lifespan. While overheating your battery may even cause the cells to explode, leak, or damage your device.

Battery Specifications of 18650 battery: 

Here are the specifications of the 18650 battery that you can consider before buying the batteries for yourself. 

Battery Size: 

Battery size is very important as you cannot interchange the batteries with different battery sizes. The 18650 battery is 1170 cubic mm. 

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Protected vs Unprotected 18650 batteries: 

Obviously, both the batteries are different. 18650 Protected batteries have an electronic circuit embedded in the battery casing that protects the cell from “overcharge” heat and “over-discharge” over a current and short circuit. Protected batteries are safer than unprotected 18650 batteries. 

On the other hand, unprotected batteries are cheap but are not recommended for daily use. They should only be used when the load/draw and charging are externally monitored and controlled.

Power: 

The 3.7v, 3400mAh 18650 battery stores about 2 aH to a max of 3.5 aH. Furthermore, it can store about 10 to 13 watt-hours. Also, it has a small air conditioning unit that can cool about 9000 BTU uses about 1100 watts per hour. So, it means that it will take about 110 of the 18650 batteries to run the air conditioner for 1 hour and sometimes more than that. But, 110 batteries of 18650 type are smaller than three car batteries. 

Ability to Recharge:

The 18650 batteries are recommended because they can be recharged from 300 to as many as 2000 times. 

Recharge cycles vary and are limited because as the battery gets reused or recharged, the battery usually starts degrading due to oxidation and electrochemical degradation. And, this happens to any of the rechargeable batteries, not just the 18650 battery. 

When to Charge:

The way your recharge your 18650 battery has a great impact on your battery life. If you have the means of measuring, you should deplete the battery from 3.7v to 3v before recharging. And, if you are not sure, use it until it indicates that the battery needs to be replaced. Because, if you start recharging your battery so frequently, you are using it up without getting anything in return. 

But, every type and model of 18650 has different maximum cycles. On the other hand, the 18650 battery usually locks the device so it can't be used, common in vaping devices. 

Chemical Combinations: 

Here are some of the current chemical combinations that you can find in the 18650 battery. You need to check what your device type needs. 

LiFePO4 is lithium iron phosphate also known as IFR or LFP or Li-phosphate.

LiMn2O4 is lithium manganese oxide also known as IMR or LMO or Li-manganese (high amp draw).

LiNiMnCoO2 is Lithium manganese nickel also known as INR or NMC (high amp draw).

LiNiCoAlO2 is Lithium nickel cobalt aluminum oxide also known as NCA or Li-aluminum.

LiNiCoO2 is Lithium nickel cobalt oxide also known as NCO.

LiCoO2 is lithium cobalt oxide also known as ICR LCO Li-cobalt.

Other Features:

Nominal or peak voltage: 3.7v. Normally goes down as you use it. 

Amp-hours: Realistically, the highest available is 4000 mAh, but on average you may get 3000 mAh.

Low Self Discharge: It is a good thing and means that it will hold the charge in storage. 

Which is the Best 18650 Battery?

Are you worried about what is the best 18650 battery that you can buy for your devices? But, you don’t need to worry because here we are with the best 18650 battery choices. Panasonic, Sanyo, Samsung, and LG are the top-level 18650 cell manufacturers that make long-lasting cells in a standard size of 18 mm by 65 mm that fits all 18650 compatible devices.

Best Overall: 

Sony/Murata VTC5A: 

It is undoubtedly the best overall 18650 battery as it offers a capacity of 2600mAh and a CDR of 25A. furthermore, it is ideal for all the applications but the cell shows its greatness in the ultra high drain devices. If you want both "Peace of Mind" along with the demanding needs of your devices to be satisfied, then this should be your go-to cell.

CDR/Capacity: 35A/2600mAh

Weight: 47.1g (variation of 1.5g)

Nominal Voltage: 3.6v 

Maximum Voltage: 4.2v

Rechargeable: Yes

Apart from this, you can also go for Molicel P26A, Samsung 20S, and 25R, and Panasonic NCR18650G. For the best 18650 battery for flashlights or torches, you can consider getting  Sanyo GA 3500 mA or Epoch 18650 3500mAh 8A Protected Button Top Battery.