Battery runtime & discharge check

Defaults are the numbers from the combat robot: four N20 motors stalled plus a servo and the electronics. Change them for your build.

Battery runtime & discharge check

Capacity (mAh)

Cells in series

Average draw (A)

Peak / stall draw (A)

Cell continuous C-rate

Protection board limit (A)

Runtime uses 85 % usable capacity (LiPo below ~3.3 V/cell is off-limits). Peak check compares against both the cell's continuous rating and the board's trip point.

How to read it

Runtime assumes 85 % of the label capacity is usable — discharging LiPo below ~3.3 V/cell shortens its life.
Required C-rate is peak current divided by capacity in Ah. Consumer pouch cells manage 1–2 C; "high-discharge" RC cells 5–30 C.
The protection board trips on peaks, not averages. Four stalled motors are a peak.

The full selection story — and the four options that lost — is inChoosing a Battery for a Small ESP32 Robot.