Amp-hours vs Watt-hours

Definition

Amp-hours (Ah) are charge. Watt-hours (Wh) are energy. They convert with Wh = Ah × V at the nominal battery voltage. A 100 Ah 12 V pack is 1,200 Wh at 100% DoD; the same 100 Ah at 24 V is 2,400 Wh. Runtime and array math should use watt-hours (or Ah together with voltage). Comparing Ah across different voltages is meaningless.

Calculators that use this

• battery storage

  Amp-Hours (Ah) to Watt-Hours (Wh) Converter

  Convert battery amp-hours to watt-hours for 12V, 24V and 48V systems. Wh = Ah × V.

• battery storage

  Battery Runtime Calculator

  Estimate how many hours a 12V, 24V or 48V battery will last under a given load. Accounts for LiFePO4 and lead-acid depth of discharge (DoD).

• battery storage

  Battery Bank Sizer for RV/Van

  Size a 12V, 24V or 48V house battery bank from daily watt-hours, days of autonomy and LiFePO4 or lead-acid depth of discharge.