Sizing Guide
Work out watt-hours from your devices, add inverter loss, then pick a power station that covers running and surge watts.
Too small and you run out of power. Too large and you pay for weight you do not need. Four steps:
1. List running watts
Use the watts on the device, or Watts = Amps × Volts. For a fridge or anything that cycles, a watt meter is better than the startup number on the sticker. Laptop bricks usually list watts more accurately than the laptop itself.
2. Multiply watts × hours
| Device | Watts | Hours | Watt-hours |
|---|---|---|---|
| Laptop | 60W | 4 | 240Wh |
| LED lantern | 10W | 6 | 60Wh |
| Mini fridge | 50W | 8 | 400Wh |
| Phone charger | 15W | 3 | 45Wh |
| Total | 745Wh |
3. Divide by 0.85 for inverter loss
The calculator and this guide use the same factor: about 15% lost converting DC battery energy to AC.
Example: 745 Wh ÷ 0.85 ≈ 876 Wh. Look for at least ~900 Wh of rated capacity.
4. Check continuous AC watts
Add the running watts of devices you will use at the same time. The station’s continuous AC rating should meet or exceed that. Motors also need surge headroom.
When unsure, round up.
Rough sizes
- Phones, lanterns, laptops: 300–500 Wh
- Mini-fridge, CPAP, small tools: 700–1500 Wh
- Microwave and heavier loads: 2000 Wh+