Quick reference
| Load | Approx. planning runtime* |
|---|---|
| 25 W | ~38 h |
| 40 W | ~24 h |
| 100 W | ~9.5 h |
| 250 W | ~3.8 h |
*Using 12.8 V, 90% DoD, 92% efficiency and 10% reserve.
Why it varies
Real runtime changes with temperature, battery age, discharge rate, wiring, inverter losses and BMS behavior. Use manufacturer limits for safety and sizing.