Calculate battery charge and discharge rates from capacity and current. Enter any two values to compute the third.
Common C-rates and their corresponding discharge times.
| C-Rate | Discharge Time | Typical Use |
|---|---|---|
| 0.1C | 10 hours | Trickle / maintenance charge |
| 0.2C | 5 hours | Slow standard charge |
| 0.5C | 2 hours | Standard discharge |
| 1C | 1 hour | Rated capacity discharge |
| 2C | 30 minutes | High power / RC models |
| 5C | 12 minutes | Burst discharge (drones) |
| 10C | 6 minutes | Extreme power applications |
C-rate is a measure of the rate at which a battery is charged or discharged relative to its capacity. A 1C rate means the battery delivers its full rated capacity in one hour. For example, a 2000 mAh battery at 1C provides 2 A of current. A 0.5C rate would take two hours to fully discharge.
C-rate is calculated by dividing the charge or discharge current (in amps) by the battery capacity (in amp-hours): C-rate = Current (A) ÷ Capacity (Ah). For a 3000 mAh battery drawing 6 A, the C-rate is 6 ÷ 3 = 2C.
At 1C, a battery discharges its full rated capacity in approximately one hour. At 2C, it discharges in about half an hour, delivering twice the current. Higher C-rates provide more power but reduce effective capacity, increase heat, and can shorten battery lifespan.