Battery Calculator — RC Power Planning

The C-rating tells you the maximum safe continuous discharge rate. A 30C 5000mAh battery can deliver 30 x 5 = 150 amps continuously. Higher C-ratings mean the battery can deliver more current without overheating or puffing. Always choose a battery with a C-rating that exceeds your motor maximum draw.

The cell count determines voltage. 2S (7.4V) suits smaller models. 3S (11.1V) is the most common for general RC use. 4S (14.8V) and 6S (22.2V) are used for high-performance models. Match the cell count to your ESC and motor specifications.

Discharging a LiPo below 3.3V per cell damages it permanently. The usable capacity is about 80% of the rated capacity. Never run a LiPo flat — use a low-voltage alarm. For maximum lifespan, some pilots only use 70% of capacity.

Run time (mins) = (Usable capacity in Ah / Average current draw in A) x 60. For example, a 5000mAh battery at 80% usable (4000mAh) with 20A average draw gives 0.2 hours = 12 minutes. Actual run time varies with throttle usage.