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18650 battery
18650: 3.6 V rechargeable lithium-ion cell, 18 mm × 65 mm, about 3,000 mAh (10.8 Wh). Same battery: INR18650, ICR18650, NCR18650.
3.6 Vvoltage
18 mmdiameter, 0.71 in
65 mmlong, 2.56 in
≈ 3,000 mAhcapacity
18650: what to know
- The number is the size: 18 mm in diameter and 65.0 mm long, the 0 marking a cylinder.
- Buy from brands that publish real ratings (Samsung, LG, Sony / Murata, Panasonic, Molicel); cells claiming 5,000 mAh or more in an 18650 are fake.
18650 equivalents
INR18650ICR18650NCR18650
Can I use another battery instead of an 18650?
| Battery | Size | Volts | Works? | Why |
|---|---|---|---|---|
| CR123A | 17 mm × 34.5 mm | 3 V | No | 3 V, not rechargeable; 18650 devices expect 3.6 V. |
| 21700 | 21 mm × 70 mm | 3.6 V | No | Different width: 21 mm vs 18 mm. |
What uses an 18650 battery?
- High-power flashlights
- Power banks and laptop battery packs
- E-bike and power-tool packs (as cells inside)
- Vape mods
Protected 18650s are 1–4 mm longer (about 67–69 mm) and may not fit tight tubes. Flat-top and button-top versions exist.