The numbers on a flashlight battery are simply its size: 18650 means 18 mm wide and 65 mm long, 21700 means 21 by 70, and 26650 means 26 by 65. Pick the wrong one and it will not fit, or worse, it will fit but not suit the device. This guide explains the sizes, what protected and unprotected cells mean, and four XTAR batteries to match to your torch.
Battery sizes: what the numbers mean
The first two digits are the diameter in millimetres, the next two are the length, and the last digit shows it is cylindrical. A larger cell holds more charge: the 26650 and 21700 batteries here are 5200mAh and 5000mAh, compared with 3500mAh for the 18650. Always check what size your flashlight takes before you buy.
Protected or unprotected
A protected cell has a small circuit that guards against overcharge, over-discharge and short circuit. An unprotected, or RAW, cell has none, so the device itself must provide the protection. If you are not sure, a protected cell is the safer choice.
For everyday flashlights: protected 18650
The XTAR 18650 with a built-in USB-C port is a protected 3500mAh cell with 10A discharge. You charge it directly from a phone charger or power bank, with no separate charger needed. It suits high-drain flashlights from brands like Klarus, Olight, Imalent, Sofirn and Ledlenser.
Actual photos of the product we stock
For high-lumen torches: RAW cells
The XTAR 18650 RAW is an unprotected 3500mAh flat-top cell with 10A continuous discharge, for tactical torches and vape mods that manage their own protection. The XTAR 21700 RAW is a 5000mAh unprotected cell rated 35 to 90A, built for serious current draw, and it is not a first battery for someone new to Li-ion cells.
Actual photos of the product we stock
Actual photos of the product we stock
For extra runtime: 26650
If your flashlight takes a 26650, the XTAR 26650 gives 5200mAh with a flat top and a built-in protection circuit against overcharge, over-discharge and short circuit. It has 10A continuous discharge and low internal resistance for steady output.
Actual photos of the product we stock
| Feature | XTAR 18650 RAW Battery | XTAR 18650 Battery | XTAR 21700 RAW Battery | XTAR 26650 Battery |
|---|---|---|---|---|
| Product | ||||
| Price | KSh 1,600 | KSh 2,500 | KSh 2,300 | KSh 2,700 |
| Battery Size | 18650 | 18650 | 21700 | 26650 |
| Capacity | 3500mAh | 3500mAh | 5000mAh | 5200mAh (highest) |
| USB Rechargeable | No | Yes | No | No |
| Protection Type | Unprotected | Protected | Unprotected | Protected |
| Energy | 12.6Wh | 12.6Wh | 18Wh | 18.72Wh (highest) |
| Max Continuous Discharge | 10A | 10A | 35A | 10A |
| Stands out | Highest capacity, energy | |||
| Suits | Tactical flashlights, high-lumen torches and vape mods with their own battery management | High-drain LED flashlights from brands like Klarus, Olight, Imalent, Sofirn and Ledlenser | High-lumen flashlights, tactical torches, and devices that manage their own battery protection | Flashlights that take a 26650 cell and benefit from extra runtime |
| Link | View & Buy | View & Buy | View & Buy | View & Buy |
Using lithium cells safely
- Match the size and chemistry to your device and charger.
- Use unprotected cells only in devices that provide their own protection.
- Do not leave cells charging unattended, and never use damaged cells.
Which one to buy
For most torches, the protected USB-C 18650 is the easy choice. For high-drain use, choose RAW cells only if you know your device protects them. For a 26650 torch, take the protected 26650.
Other options worth a look
- XTAR 21700 Battery, 5000mAh, Built-in USB-C, 10A DischargeKSh 3,000
- 1Kon 26650 Battery, 3000mAh, Protected Li-ionKSh 2,000
- XTAR INR 18650 Battery, 2600mAh, 20A/30A High-DrainKSh 1,400
- XTAR AA USB-C Rechargeable Battery, 2450mAh, 4-PackKSh 3,500
- XTAR AA 3960 Rechargeable Battery, 2500mAh, 4-PackKSh 3,000
- XTAR AAA Rechargeable Battery, 1000mAh, 1.5V, 4-PackKSh 2,700
- PeetPen 2D Battery, 1800mAh, 3.7V, for L80 FlashlightKSh 600
- XTAR VC8S 8-Slot Charger | 3A USB-C Fast Charge, LCD DisplayKSh 8,000
Check your flashlight's battery size, then open the matching card to check the current price and stock.
Check the XTAR 18650 USB-C batteryKSh 2,500 · In stock
Where you would use it
- Everyday torch A protected USB-C 18650 charged from a power bank, ready for the next night.
- High-lumen tactical torch A 21700 RAW cell for devices that demand heavy current and manage their own protection.
- Long runtime A 26650 cell gives extra runtime in torches built for it.
Frequently asked questions
It is the size of the cell: 18 mm wide and 65 mm long.
A protected cell has a circuit against overcharge, over-discharge and short circuit, while an unprotected RAW cell relies on the device for protection.
Yes. The version with a built-in USB-C port charges from a phone charger or power bank.
The XTAR 26650 at 5200mAh, followed by the XTAR 21700 RAW at 5000mAh.
