⚡Power & Energy
Battery Charge Time Calculator
Estimate the time required to charge a battery from a given charge current. Supports Li-Ion, NiMH, and lead-acid chemistries.
Formula Explanation
The charge time is calculated using the battery capacity, charge current, and efficiency:
Tcharge = (Capacity × (Target% − Initial%)) / (Icharge× Efficiency)
The energy required to charge the battery is:
E (Wh) = (Capacity / 1000) × V × (Target% − Initial%) / 100
The C-rate represents the charge current relative to the battery capacity:
C-Rate = Icharge (mA) / Capacity (mAh)
Note:This calculation assumes the battery is charged in CC (Constant Current) mode. The CV (Constant Voltage) phase at the end of charging may add additional time, especially when charging above 80–90%.
Reference: Charge Time by Capacity and Current
Assuming 3.7 V Li-Ion, 85% efficiency, 20% to 80% charge.
| Capacity | 500 mA | 1000 mA | 2000 mA |
|---|---|---|---|
| 500 mAh | 0.7 h | 0.4 h | 0.2 h |
| 1000 mAh | 1.4 h | 0.7 h | 0.4 h |
| 2000 mAh | 2.8 h | 1.4 h | 0.7 h |
| 3000 mAh | 4.2 h | 2.1 h | 1.1 h |
| 5000 mAh | 7.1 h | 3.5 h | 1.8 h |
| 10000 mAh | 14.1 h | 7.1 h | 3.5 h |