Battery kW, kWh and Ah explained
Understand battery power, stored energy and amp-hours before comparing backup options.
Battery kWh measures stored energy. Battery kW describes the power that the system and inverter can supply. Ah is charge capacity at a stated voltage. Ah alone cannot compare batteries at different voltages: 100 Ah at 48 V stores more nominal energy than 100 Ah at 12 V.
Start at the loads
Multiply essential watts by backup hours for delivered energy, then allow for depth of discharge and conversion efficiency. The battery backup calculator makes those assumptions visible.
Check both constraints
A battery can have enough energy for the planned duration but fail a high-power start. Confirm continuous and surge power, temperature limits, cycle life and manufacturer operating range. Compare lifecycle cost with a generator only after both options can serve the same load and hours.
Put the idea into numbers.
Open the battery backup calculator →