Usable Wh include battery voltage, discharge allowance and inverter efficiency, plus idle power. Peukert effects, ageing, temperature and shutdown voltage can reduce runtime.
How to use
- Enter the dimensions and electrical values.
- Adjust the assumptions to match your components.
- Read the result and check the technical limits below.
Formula and assumptions
Wh = V × Ah × DoD; P_DC = P_AC/η + P_idle; t = Wh/P_DC.
Calculated example
- Battery capacity
- 100 Ah
- Voltage
- 12 V
- AC load
- 100 W
- Efficiency
- 90 %
- Usable battery capacity
- 80 %
- Inverter idle power
- 5 W
- Estimated runtime
- 8.2679 h