Convert between amp-hours, kilowatt-hours and runtime for a battery bank.
Amp-hours only describe energy once multiplied by voltage. The C-rate matters because high discharge rates reduce effective capacity, especially in lead-acid chemistries. A battery rated at the 20-hour rate delivers noticeably less capacity when discharged in two hours, an effect described by Peukert’s law.
Battery Bank Amp Hour
kWh = Ah × V ÷ 1,000; runtime = usable kWh × 1,000 ÷ load watts
kWh = Ah × V ÷ 1,000; runtime = usable kWh × 1,000 ÷ load watts Amp-hours only describe energy once multiplied by voltage. The C-rate matters because high discharge rates reduce effective capacity, especially in lead-acid chemistries.
A battery rated at the 20-hour rate delivers noticeably less capacity when discharged in two hours, an effect described by Peukert’s law.
This calculator takes 4 inputs: Bank capacity, System voltage, Load, Usable depth of discharge. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.