Battery is the source power of torches. There are mainly four types of batteries - Li-ion Rechargeable Batteries, Nickel-Metal Hydride (NiMH) Rechargeable Batteries, Lithium (NOT Lithium-Ion) Non-Rechargeable Batteries and Alkaline Non-Rechargeable Batteries.
14500 Rechargeable Li-ion Battery: These batteries are similar in size to a regular AA battery but can drive the light to higher output. However, remember to check the lantern manual carefully because some lights operating on a regular disposable AA alkaline battery may not be compatible with a 14500 rechargeable battery.
16340 Rechargeable Li-ion Battery: These are close in size to an one-off CR123A battery. Similarly, just check the battery compatibility carefully. Most CR123A lights in the market can use 16340, but since the voltage is different, you would better understand which battery types and voltages the light accepts before trying a different battery.
18650 Rechargeable Li-ion Battery: The 18650 Li-ion battery is an extremely popular battery source for today's flashlights due to the outstanding ratio of power to size. 18650 batteries are generally 3.6/3.7 volts and have various mAh (milliamp) ratings. The mAh rating is solely for determining how often you will have to recharge your battery. The higher the mAh rating, the longer the run time between charges. The maximum capacity for 18650 at the moment is 3500mAh. Generally speaking. 18650 batteries are not designed to operate optimally in temperatures below freezing.
26650 Rechargeable Battery: This is a high performance/high capacity battery capable of offering excellent power for high-drain or high-power devices or tools. The size of a 26650 battery is a larger diameter and longer length. A 26650 battery has a high mAh rating up to 5000mAh with a long run time.
21700 Rechargeable Battery: 21700 batteries are rechargeable lithium-ion cells that are used to power various devices like flashlights and vaping accessories. Similar to other lithium-ion cells, it is named as per its dimensions. The exact size is 21mm in diameter and 70mm in length. 21700 batteries are just a little bit larger than 18650, but due to the higher capacity, it has an obvious advantage on run time. Currently, the maximum capacity for 18650 is 3500mAh, while for 21700, it’s 5000mAh. 21700 torches can offer more output and longer run time while keeping portable. Some 21700 lights in the market are also compatible with 18650 batteries for users’ options.
One crucial factor to remember is that 21700 batteries can be both protected and unprotected. For this reason, it is essential to do your research before choosing your gear.
These come in AAA, AA, 9-Volt, and small cylinder ( CR123A) sizes. Since their self-discharge is slow, their shelf life can get as long as 10 years (different brands may vary). Additionally, they perform perfect in below freezing temperatures. If your lanterns would be used in extremely cold situations, make sure to use CR123A battery lights.
These are the most affordable and easiest accessible but not rechargeable. You will find them in these sizes: AAA, AA, C, D, 9-volt, and button cells. One disadvantage of alkaline batteries is they tend to leak and may damage the devices. We suggest you power up your device once a week to decrease the risk of leakage. If your devices will not be used frequently, it would be safer to remove the battery. Another downside due to the low power output, the run time and lumens you can get from this battery is not very good.
There are so many different types of batteries using on torches that you may get confused on selection. Firstly, you need to know what you need the LED flashlights for. Below we will offer you some guide.
For frequent use or everyday carry, rechargeable batteries would be highly recommended. In the long run, they save cost and offer convenience. Now, some brands have released rechargeable batteries with a USB port on top, which allows charging with just a cable. This way brings much more convenience and cost down because users do not need a separate charger any more.
For storage or packed lights, we would suggest you use lithium battery lights because they have the lowest self-discharge rate of any chemistry. Good ones are usable even after years of storage.
Avoid lights with esoteric batteries for wilderness areas. Modern emitters get great performance out of AA and AAA cells, which are more easily accessible and affordable. Anyway, if you plan to spend days outside, remember to prepare more batteries for spare use.
Due to the portable size, high capacity and rational price, 18650 flashlights are really popular for outdoor use. However, they are not designed to operate optimally in temperatures below freezing. So, if you are going adventure in cold temperature places, the lithium non rechargeable CR123A would be a wise option.
For safety, try to get a name brand and high quality batteries. Be careful of some super cheap cells in the market.