Beyond 18650: A Guide to Popular Battery Sizes You Should Know
When it comes to high-performance rechargeable batteries, the 18650 has long been the gold standard. But the battery world is much bigger than just one size. Whether you’re powering flashlights, vape devices, cameras, or electric tools, understanding the range of popular battery sizes can save you time, money, and frustration. Here’s a guide to some of the most commonly used battery sizes and what makes them popular.
1. 21700 Batteries – The New Heavyweight
The 21700 battery is slightly larger than the 18650, measuring 21mm in diameter and 70mm in length.
- Uses: High-drain devices like power tools, electric bikes, high-capacity flashlights, and vape mods.
- Advantages: Offers up to 50% more capacity than a standard 18650, with higher energy output and longer run times.
- Popular Models: Samsung 40T, LG M50, Panasonic NCR21700B
For users looking for more power without changing device form factors drastically, 21700 is quickly becoming a go-to.
2. 26650 Batteries – For Maximum Capacity
These are larger cylindrical lithium-ion cells, measuring 26mm x 65mm.
- Uses: High-capacity flashlights, e-bikes, solar power storage, and backup power solutions.
- Advantages: High mAh rating, making them ideal for devices that need long runtimes without frequent recharging.
- Popular Models: Keeppower 5200mAh, Efest 5200mAh
While bulkier, they’re perfect for situations where runtime is more important than size.
3. CR123A and 16340 Batteries – Compact but Powerful
- Size & Type: CR123A is 34mm x 17mm, while the rechargeable 16340 is similar in size but lithium-ion.
- Uses: Tactical flashlights, cameras, alarm systems, and some vape pens.
- Advantages: Small form factor with high voltage output. 16340s are rechargeable, making them cost-effective long-term.
- Popular Models: Surefire CR123A, Keeppower 16340
These are often overlooked, but their compact size and high voltage make them a staple for specialized devices.
4. AA and AAA Rechargeables – The Everyday Workhorses
Although not as flashy as 18650s or 21700s, AA and AAA batteries remain essential. Rechargeable NiMH or lithium options give them a second life and better performance.
- Uses: Remote controls, cameras, toys, LED lights.
- Advantages: Widely available, inexpensive, and versatile. Rechargeable versions reduce waste.
- Popular Models: Eneloop Pro AA, Duracell Rechargeable AAA
5. 14500 Batteries – 18650’s Smaller Cousin
- Size: 14mm x 50mm
- Uses: Smaller flashlights, vape devices, and some portable electronics.
- Advantages: Offers similar voltage as an 18650 but in a more compact size, perfect for portable devices.
- Popular Models: Keeppower 14500 800mAh
Choosing the Right Battery for Your Device
Picking the right battery isn’t just about size—it’s about capacity, voltage, and whether your device can handle higher discharge rates. Always check manufacturer recommendations to avoid damaging your electronics or reducing battery lifespan.
By expanding your knowledge beyond the 18650, you’ll be better prepared to choose the best battery for every application—whether you need maximum power, compact size, or long runtime.