Off-Grid Solar Calculators

Battery storage

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

Convert battery amp-hours to watt-hours with Wh = Ah × V. A 12V 100Ah pack is 1,200 Wh nameplate (about 1.14 kWh usable at 95% LiFePO4 DoD). Use watt-hours to compare 12V, 24V and 48V banks; amp-hours alone are not energy.

Inputs

Ah

Rated amp-hour capacity on the battery label.

System or series-string voltage printed on the pack.

Results

Energy
1,200Wh

Nameplate watt-hours = Ah × V.

Energy
1.20kWh

Same energy in kilowatt-hours.

Recommended gear

Engineering methodology

Watt-hours = amp-hours × nominal volts (Wh = Ah × V). Kilowatt-hours = watt-hours ÷ 1000. This is nameplate energy at the labeled voltage, not usable energy. Usable watt-hours still require a depth-of-discharge factor.

Nameplate watt-hours vs usable watt-hours

Wh = Ah × V is the labeled energy. Usable Wh = Ah × V × DoD. A “12 V 100 Ah” LiFePO4 pack is 1,200 Wh on paper and about 1,140 Wh at 95% DoD. Lead-acid at 50% DoD is 600 Wh from the same Ah label.

Comparing 12V and 24V batteries

Always convert to watt-hours. 100 Ah at 24 V is 2,400 Wh—twice 100 Ah at 12 V. Kilowatt-hours are watt-hours ÷ 1,000. Do not compare amp-hours across voltages.

Frequently asked questions

How many watt-hours is a 12 V 100 Ah battery?

Nameplate energy is 100 × 12 = 1,200 Wh (1.2 kWh). At 95% DoD that is about 1,140 Wh usable. At 50% DoD it is 600 Wh usable.

Should I use 12 V or 13.2 V for LiFePO4?

This converter uses nominal system voltage (12 / 24 / 48 V), the usual nameplate convention. A “12 V” LiFePO4 pack rests nearer 13.2 V; using 12 V is conservative for energy comparisons across chemistries.

How do I compare a 12 V bank with a 24 V bank?

Convert both to watt-hours. Ah × V puts them on the same energy scale. A 100 Ah 24 V pack is 2,400 Wh, twice a 100 Ah 12 V pack.

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