How to convert Wh to Ah
Amp hours (Ah) = Watt hours (Wh) ÷ Voltage (V)
Worked example
Your daily loads add up to 1,000 Wh. On a 12 V system that's 1,000 ÷ 12 = 83.3 Ah per day. On a 24 V system the same energy is only 41.7 Ah, which is why bigger systems move to higher voltages: the current, and the cable size, halves.
Using the result
- To size a battery bank, divide the Ah per day by the depth of discharge you're happy with. The battery bank size calculator does this for you.
- To find your daily Wh in the first place, list your appliances in the 12 V power consumption calculator.
- If the energy passes through an inverter, add around 10–15% for inverter losses.
Frequently asked questions
How many amp hours is 1 kWh?
At 12 V, 1 kWh is about 83 Ah. At 24 V it's about 42 Ah, and at 48 V about 21 Ah.
Why do I get a different answer at a different voltage?
Amp hours depend on voltage. The same amount of energy needs half the amp hours at twice the voltage.