Electrical units and conversion

Battery Ah to kWh converter

Amp-hours describe charge, not energy. Multiply by the battery's nominal voltage to get watt-hours, then divide by 1,000 for kilowatt-hours.

How do you convert amp-hours to kilowatt-hours?

Multiply amp-hours by the battery’s nominal voltage to get watt-hours, then divide by 1,000. A 200 Ah battery at 48 V nominal stores 200 × 48 = 9,600 Wh, which is 9.60 kWh. At 12 V the same 200 Ah is only 2.40 kWh — which is why amp-hour figures are meaningless without the voltage. The conversion is exact; what it gives you is nominal DC energy, before depth-of-discharge and inverter losses.

Your inputs

Capacity in amp-hours

Nominal battery voltage

Use the nominal voltage printed on the battery, not the resting or charging voltage.

Common system voltages

9.60 kWh

of nominal stored energy

200 Ah at 48 V nominal. This is DC energy before depth-of-discharge and inverter losses.

Exact given your inputs

Amp-hours: 200.0 Ah
Voltage: 48.0 V
Watt-hours: 9,600 Wh
Kilowatt-hours: 9.60 kWh

This is nominal DC energy

The conversion itself is exact arithmetic, but the result is the energy stored on the DC side at nominal voltage. Usable energy at an AC outlet is lower once depth of discharge and inverter efficiency are applied.

Method

200 Ah × 48 V = 9,600 Wh
9,600 Wh ÷ 1000 = 9.600 kWh

Assumptions

Nominal voltage is used throughout; real pack voltage varies with state of charge.
No depth-of-discharge limit, inverter loss or temperature effect is applied.
Lead-acid capacity ratings assume a specific discharge rate — a 100 Ah lead-acid battery does not deliver 100 Ah at high current.
No depth of discharge, reserve or inverter efficiency is applied here — Ah × V ÷ 1000 and kWh × 1000 ÷ V are exact inverses of each other.

What can change the result?

Which voltage you use — nominal, resting or charging voltage give different answers
Battery chemistry, since usable depth of discharge differs sharply between lead-acid and lithium
Discharge rate, which reduces effective lead-acid capacity (Peukert effect)

Common battery ratings converted

The conversion is exact arithmetic; kilowatt-hours are rounded to two decimals for display. Usable energy at an AC outlet is lower.
Amp-hours	Nominal voltage	Watt-hours	Kilowatt-hours
100 Ah	12 V	1,200 Wh	1.20 kWh
200 Ah	12 V	2,400 Wh	2.40 kWh
100 Ah	24 V	2,400 Wh	2.40 kWh
200 Ah	48 V	9,600 Wh	9.60 kWh
280 Ah	51.2 V	14,336 Wh	14.34 kWh
400 Ah	48 V	19,200 Wh	19.20 kWh

Two traps in this conversion

The first is voltage choice. A 48 V lithium pack actually sits around 51.2 V nominal, and using 48 V understates its energy by about 6%. Use the figure the manufacturer calls nominal, not the resting voltage you measure or the voltage the charger pushes.

The second is chemistry. A 100 Ah lithium battery will typically deliver 90–100 Ah in practice; a 100 Ah lead-acid battery discharged quickly delivers considerably less than its rating, and taking it below 50% shortens its life sharply. The conversion is the same either way, but what you can usefully take out is not.