UPS / Battery Backup Time

Battery string sizing, discharge current and backup runtime from usable battery energy (simplified constant-capacity model).

Inputs

Battery capacity C₁₀ Ah

DC bus voltage U_dc V

Cell voltage U_cell V

Load power P W

Inverter efficiency η —

Depth of discharge —

Target backup time min

Results

Note — Simplified constant-capacity model; real runtime drops with discharge rate (C/1 h vs C/10 h) and temperature. Apply the battery manufacturer's capacity correction and end-of-discharge voltage. Confirm against the UPS nameplate and a certified engineer.