Power station runtime chart
Estimated runtime on the AC outlets for common power station sizes, at 85% inverter efficiency.
| Device | 300 Wh | 500 Wh | 1000 Wh | 2000 Wh |
|---|---|---|---|---|
| Phone charging (10 W) | 25 h 30 min | 42 h 30 min | 3 days 13 h | 7 days 2 h |
| CPAP, no humidifier (40 W) | 6 h 1 min | 10 h 18 min | 21 h 15 min | 42 h 30 min |
| Laptop (60 W) | 3 h 56 min | 6 h 44 min | 13 h 55 min | 28 h 20 min |
| Full-size fridge, average (65 W) | 3 h 37 min | 6 h 11 min | 12 h 48 min | 26 h 9 min |
| TV (100 W) | 2 h 18 min | 3 h 56 min | 8 h 9 min | 16 h 52 min |
| Space heater, low (750 W) | 17 min | 28 min | 59 min | 2 h 2 min |
How to work out power station runtime
Runtime (h) = capacity (Wh) × efficiency ÷ load (W)
- Find the capacity in Wh on the spec sheet. If it is only given in mAh, multiply by the cell voltage (often 3.2 V or 3.7 V) and divide by 1,000.
- Add up the running watts of everything plugged in at the same time. For appliances that cycle, like fridges, use the daily average.
- Multiply the capacity by 0.85 for AC outlets or 0.95 for DC outlets, and divide by the load.
Power stations use lithium cells that deliver close to their full rating even at high loads, so a power station’s runtime stays predictable from 10 W to its maximum output. The calculator still applies a small Peukert correction for heavy loads. For the full method, see how battery runtime is calculated.
Watts, surge and runtime are three different limits
- Capacity (Wh) sets how long it runs.
- Rated output (W) sets the largest load it can power continuously. A 1,000 Wh station rated at 1,000 W cannot run a 1,500 W kettle, however full it is.
- Surge (W) covers the brief start-up spike of motors and compressors. Fridges, pumps and power tools need it.
To size a station for a set number of hours, use the battery size calculator. If you are building your own system with separate batteries, the 12V battery runtime calculator and solar battery calculator fit better.