Calculate how long an inverter can run a load from a battery bank.
Inverter standby consumption matters disproportionately at light loads: a 20 W standby draw is trivial against 800 W but dominates a 50 W night-time load. Off-grid systems often lose more energy to inverter standby overnight than to the actual loads, which is why sleep modes exist.
Inverter Runtime
Runtime = usable kWh × 1,000 ÷ (load ÷ efficiency + standby draw)
Runtime = usable kWh × 1,000 ÷ (load ÷ efficiency + standby draw) Inverter standby consumption matters disproportionately at light loads: a 20 W standby draw is trivial against 800 W but dominates a 50 W night-time load.
Off-grid systems often lose more energy to inverter standby overnight than to the actual loads, which is why sleep modes exist.
This calculator takes 5 inputs: Battery capacity, Usable depth of discharge, Load, Inverter efficiency, Inverter standby draw. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.