21700
A rechargeable lithium-ion cell 21 mm across and 70 mm long. The larger successor to the 18650 in EV and power-tool packs.
- Voltage
- 3.6 V
- Chemistry
- Li-ion
- Size
- 21 × 70 mm
- Capacity
- 3000–5000 mAh
Specifications
| Type | Cylindrical |
|---|---|
| Chemistry | Li-ion |
| Nominal voltage | 3.6 V |
| Diameter | 21 mm |
| Height | 70 mm |
| Typical capacity | 3000–5000 mAh |
| Rechargeable | Yes |
| Also sold as | INR21700, NCR21700, 2170 |
Equivalent batteries
These codes describe the same physical cell as the 21700.
Can I replace 21700 with…
Cells that fit the same space but differ in chemistry or voltage.
Check before you swap. Batteries with similar dimensions are not always interchangeable with the 21700. Always verify voltage, chemistry and the requirements printed in your device manual before fitting a replacement.
21700 questions
What batteries are equivalent to the 21700?
The 21700 is sold as INR21700, NCR21700. All of these describe the same 21 × 70 mm li-ion cell at 3.6 V.
Can I use a 18650 instead of a 21700?
In many low-drain devices, yes — the sizes match. Check the voltage and chemistry against your device's requirement first, because a small voltage difference can matter in calibrated equipment.
How long does a 21700 last?
A 21700 holds a typical 3000–5000 mAh. Real runtime depends entirely on how much current your device draws and whether it is used continuously.
Is the 21700 rechargeable?
Yes, the 21700 is a rechargeable cell and must be charged in a charger designed for its chemistry.
Related batteries
Other cylindricals in the index.