How long battery fit last

Estimate usable energy and runtime when load no dey change.

Your numbers

Runtime wey di model estimate

—

E leave out capacity changes with discharge rate, ageing, temperature, voltage sag, standby losses and battery management limits.

Formula

Use t = VCfη/P. V na nominal voltage for V, C na capacity for Ah, f na usable discharge fraction, η na conversion efficiency as fraction, and P na constant load for W. Runtime t dey for hours.

Estimate usable energy and runtime when load no dey change.

Example wey show the calculation

Nominal voltage of di battery (V): 12
Di battery capacity (Ah): 100
Discharge depth wey you fit use (%): 80
Efficiency of conversion (%): 90
Power of di steady load (W): 100

Runtime wey di model estimate: 8.64 hours
Usable energy wey reach di load: 864 Wh

Where e fit work and limits

E leave out capacity changes with discharge rate, ageing, temperature, voltage sag, standby losses and battery management limits.

We check inputs for missing values and allowed ranges. Result wey pass the finite numeric range no go show. Rounding affect wetin display, while calculation use the model numeric precision.

Check your units and assumptions before you rely on result. Changing label no convert currency or physical unit.

Version of di formula: f999924e8954 · Example don get check: 2026-10-30

Method