Which Flashlight Batteries Are Best?

Which Flashlight Batteries Are Best?

This article discusses the best batteries for flashlights in terms of charge time, usage time, safety, and other aspects, and concludes that lithium-ion batteries are the winners in the power supply of modern portable electronics. Lithium-ion 18650 batteries are the most common size.

1. Rechargeable flashlight battery

1.1 Li-ion battery

Lithium-ion batteries are the classic of modern commercial rechargeable batteries, and in recent years, as the cost of producing batteries has dropped dramatically, they have become more economical than anything else on the market. Today, many portable electronic devices, electric shavers, Laptops and even Tesla use lithium-ion batteries in their electric cars.

Common models are 14500, 18650, and 21700. Their nominal voltage is 4.2V or 3.7V. In addition, unlike NiCd and NiMH batteries, 18650 batteries have no memory effect and can be used for a longer period of time.

Advantages of lithium-ion batteries

Higher energy density (more electricity can be stored in the same volume)

Higher voltage and current output (meaning higher lumen output)

Improved performance at low temperatures, up to -40ºC

High output models can generate enough power to drive modern high performance LEDs

Super fast charging when using the right battery/charger combination

No battery memory effect issues

Lithium-ion battery disadvantages

Older devices cannot use these batteries

Conventional batteries are ubiquitous, rechargeable batteries are less available

There are many product brands, sizes, and models, which may be difficult for beginners to understand

may not be allowed on the plane

Lithium-ion batteries cannot be fully discharged, or permanent damage may occur

1.1.1 🔋10440 battery (AAA battery)

The diameter of the 10440 battery is 10mm, and the height is 44mm. The battery capacity of the 10440 battery is generally small, only a few hundred milliamp hours, and it is mainly used in microelectronic products such as flashlights, stereos, and remote controls.

Olight 10440 Battery Flashlight: Olight does not currently sell AAA rechargeable batteries. The Olight I3t comes with non-rechargeable AAA batteries. (Please do not put 10440 3.6V Li-ion rechargeable battery into I3T, otherwise it may be dangerous)

1.1.2 🔋14500 battery (AA rechargeable battery)

The diameter is 14mm and the height is 50mm. The voltage of this kind of battery is generally 3.2V or 3.7V. The capacity is relatively small, slightly larger than the 10440 battery, generally 1600mAh. It has excellent discharge performance and is widely used. Its size is the same as AA battery, and it is compatible with many products.

Olight 14500 battery flashlight: S1A, i5R EOS (i5T EOS charging version) Olight does not sell 14500 rechargeable batteries separately. 14500 1420mAh Lithium-Ion battery is included in the accessories that come with the flashlight.

1.1.3 🔋1630 rechargeable battery (rcr123a rechargeable version)

The diameter is 16 mm and the height is 34 mm. The battery is short and has a small capacity. It can be used in products such as glare flashlights, LED flashlights, and headlights.

Cytac's 3.7V rechargeable Li-Ion RCR123A/16340 (650mAh) battery can be charged up to 1,000 times. This makes them a cost-effective solution for flashlights/torches, digital cameras, and high-performance devices. These are high-density rechargeable batteries with built-in PCB protection and voltage regulators for safe and efficient operation. Most of Olight's S-Series standard Equipped with CR123A batteries, compatible with 18650 batteries, many flashlights using 18650 rechargeable batteries can also use two CR123A batteries.

1.1.4 🔋18650 rechargeable battery

The diameter is 18mm and the height is 65mm. The biggest feature is that the energy density is very high, almost reaching 170Wh/kg, and the energy/volume ratio is better than other types of rechargeable batteries. Olight 18650 lithium-ion battery has triple overheat protection and over-discharge protection, safe to use Reliable, built-in overcharge and overdischarge protection circuit to ensure battery life. We usually see this kind of battery mostly, because it is a relatively mature lithium-ion battery, and the system quality is relatively stable in all aspects.

Olight flashlights using 18650 batteries: Warrior mini 2, Baton series and S2R II.

1.1.5 🔋21700 rechargeable battery

The 21700 battery is a lithium-ion battery with a diameter of 21mm and a height of 70mm. Due to the increase in size and space utilization, the energy density of battery cells and systems has been improved. Its volumetric energy density is much higher than that of 18650 batteries. Widely used in digital, electric vehicles, balance vehicles, solar lithium battery street lights, LED lights, power tools, etc.

Olight flashlights using 18650 batteries: Warrior series, Seeker 3 Pro, Freyr, Archer, Odin and Odin Turbo.

For a comparison of 18650 batteries vs 21700 batteries, you can read: 18650 vs 20700 vs 21700 battery - which is better?

1.2 NiMH battery (NiMH rechargeable battery)

These are rechargeable cylindrical batteries, but can be made in various shapes and sizes by combining multiple battery packs into a single pack. For modern LED flashlights, the main versions are available in AA and AAA sizes. They produce nominal 1.2V voltage.



As a great alternative to devices designed for original AA and AAA batteries, you can use NIMH batteries to power a variety of devices as they come in the same standard size as AA or AAA batteries and have a good shelf life.

Less likely to leak or explode



The output power is small, not suitable for high-power LED flashlights

Charging takes 10-12 hours

Some modern chargers remove the ability to charge NiMH batteries to save space and money

Falling behind due to advances in other battery chemistries

2.Non-rechargeable flashlight battery

There are non-rechargeable batteries such as your AA, AAA, C, D batteries and hundreds of examples, but any non-rechargeable battery falls into this category. (Some chargers claim to charge standard AA alkaline batteries, don't trust them.)

aa battery flashlight: i5T EOS,i5T Puls

aaa battery flashlight: i3E EOS, i3T EOS, i3T Plus

⭐2.1 alkaline battery

These are the traditional AA, AAA, C, D etc batteries you can find in supermarkets. They are usually 1.5v aaa/aa batteries.


Very easy to get, sold in almost all stores

Very small, perfect for a pen torch

Long shelf life



Does not perform well in sub-zero temperatures

Easy to leak and damage your device

Limited power output, unable to power high-performance LED torches

If you're someone who never remembers to charge your batteries, remember to carry alkaline batteries with you, but they're not environmentally friendly and expensive, on the other hand, if you forget to take them out, they can leak and damage your gear.

⭐2.2 Lithium battery (non-lithium ion battery)

I'll briefly touch on Lithium primary cells here as they are a fairly common battery and there are many different chemistries that can be used here that will produce different voltages and outputs, but I'll try to be brief.


aaa/aa size batteries: These lithium batteries will give you the best run time of any AA/AAA size battery, they have a good shelf life and are great for keeping in case of emergencies.

CR123A——CR123A lithium battery is a non-rechargeable battery, which has the outstanding advantage of high energy density. The energy density of CR123A can even reach 2.5 times that of 16340 batteries, even with the same size. The effective storage life of CR123A batteries is long, up to 10 years.

👉Why choose Olight custom batteries when buying an Olight flashlight?

Many people like to remove and replace the 18650 batteries in mobile power supplies and laptop batteries, but this is not recommended. These batteries are generally capacity type, although many batteries have the same size, but Olight batteries have greater discharge power, and due to the special circuit design, most of our flashlights use Olight batteries, and some low-lumen compact flashlights Typically use disposable replaceable batteries.


Olight lithium-ion batteries are made with high-performance cells. The 18650 2600 mAh battery is without a doubt one of the best rechargeable batteries as it is compatible with almost all flashlights and offers a good balance of capacity and price. They have battery overcharge protection and can be charged 400-500 times before needing to be replaced.

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