Start with your devices
Write down each device’s power draw in watts and the hours you expect to use it. Multiply watts by hours to estimate watt-hours, then add the results. A 60 W constant load for four hours uses 240 Wh at the device.
A two-night camping example
These numbers are illustrative planning assumptions, not measured product performance. Replace them with your device measurements.
| Device | Power | Hours | Energy |
|---|---|---|---|
| LED camp lighting | 10 W | 8 | 80 Wh |
| Laptop | 45 W | 4 | 180 Wh |
| Phone charging | 10 W | 4 | 40 Wh |
| Total | At the devices | 300 Wh | |
At 85% efficiency with a 10% reserve and no idle draw, the estimated rated capacity is 300 ÷ 0.85 ÷ 0.90 ≈ 392 Wh. This is a capacity estimate, not a product recommendation. Real charging tapers and device loads vary.
Check the peak load too
If all three example loads run together, their assumed total is 65 W. The output check must also account for any startup demand, the ports used and the manufacturer’s restrictions. A device energy budget alone does not prove compatibility.
Do not assume solar will make up the difference
This budget excludes solar replenishment. Shade, weather, panel orientation and charging limits make solar energy uncertain. Confirm panel voltage, current, connector and charging compatibility with the exact power station’s manual.
Allow for losses and a reserve
For an illustrative 85% conversion efficiency and 10% battery reserve, that 240 Wh load needs about 314 Wh of rated capacity: 240 ÷ 0.85 ÷ 0.90. These assumptions are starting points, not measured performance for a particular station.
Check compatibility separately
Enough capacity does not guarantee that a device can run. Verify continuous output, startup demand, ports and the exact model’s operating instructions. Use our calculator for an estimate, then compare manufacturer specifications.