Battery capacity
What can a 30Ah 12V battery power?
A 30Ah 12V LiFePO4 battery holds about 0.36 kWh, of which roughly 274 Wh is usable. Here is roughly how long it runs common devices — adjust any load in the calculator below.
| Device | Typical power | Run-time |
|---|---|---|
| Refrigerator | 150 W | 1.8 hours |
| CPAP | 45 W | 6.1 hours |
| TV | 90 W | 3.0 hours |
| Laptop | 50 W | 5.5 hours |
| LED lights | 40 W | 6.8 hours |
| Space heater | 1500 W | 0.2 hours |
| Ceiling fan | 60 W | 4.6 hours |
| Router | 12 W | 22.8 hours |
Calculate for your device
Run-times assume LiFePO4 (~80% usable) and typical inverter loss. Lead-acid of the same rating gives roughly 60% as long, since only ~50% is usable. To build a full system, use the system calculator.
Estimates for planning only. See the methodology.