Amp Hours to Watt Hours Converter (Ah to Wh)
Convert battery capacity from amp-hours to watt-hours at 12V, 24V or 48V. The key step when sizing solar, RV and off-grid battery banks.
Convert Amp-Hours to Watt-Hours
Conversion Result
1.200 kWh total stored energy
Lead-acid banks should only be discharged halfway for long life
Lithium iron phosphate can be discharged much deeper safely
Step-by-Step Engineering Calculation
- 1Energy:
- 2That is 1.200 kWh of stored energy at the nominal 12 V battery voltage. Usable energy is lower after depth-of-discharge and inverter losses.
Conversion Formula & Relationship
Amp-hours measure charge, watt-hours measure energy. Multiplying the charge capacity by the battery's nominal voltage gives the total stored energy, which is what you compare against daily consumption.
Standard Conversion Example
A common 100 Ah deep-cycle battery stores 100 × 12 = 1,200 Wh. At the 50% depth-of-discharge limit for lead-acid, about 600 Wh is safely usable.
Quick Reference Conversion Table
| Amp-Hours (Ah) | Watt-Hours (Wh) | Common Application / Context |
|---|---|---|
| 50 Ah @ 12V | 600 Wh | Small AGM / car battery |
| 100 Ah @ 12V | 1,200 Wh | Standard deep-cycle / RV house battery |
| 200 Ah @ 12V | 2,400 Wh | Off-grid cabin bank |
| 100 Ah @ 24V | 2,400 Wh | Same energy, half the current |
| 100 Ah @ 48V | 4,800 Wh | Home storage unit |
| 280 Ah @ 51.2V | 14,336 Wh | DIY LiFePO4 rack bank (16 cells) |
Frequently Asked Questions
Why do I need the voltage to convert Ah to Wh?
Amp-hours alone do not describe energy. A 100 Ah battery at 12 V stores half the energy of a 100 Ah battery at 24 V, so the conversion is only possible once the nominal system voltage is known.
How many watt-hours can I actually use from a 100 Ah battery?
That depends on chemistry. A lead-acid or AGM battery should only be discharged to about 50%, so roughly 600 Wh of a 1,200 Wh bank is usable. LiFePO4 tolerates 80% or more, giving around 960 Wh usable.