How We Calculate Runtimes
Every runtime on this site is a calculated estimate, not a measurement. We have not hands-on tested these power stations. Here is exactly how the numbers are produced, so you can judge them for yourself.
1. Can it run at all?
An appliance is marked as compatible only if the power station's rated continuous output is at least the appliance's running watts, and its rated surge output is at least the appliance's typical startup surge. Motors and compressors (fridges, pumps, furnace blowers) can briefly draw 2–4× their running watts when they start.
2. Usable capacity
We assume about 85% of a station's rated watt-hours reach the appliance through the AC outlets. The rest is lost in DC-to-AC conversion. Real efficiency varies by model and load; very small loads are usually less efficient.
3. Average draw
Appliances that cycle on and off are averaged using a typical duty cycle. For example, a fridge compressor might run about 35–40% of the time. We add about 8W for the inverter's own idle draw.
hours ≈ (rated Wh × 0.85) ÷ (running W × duty cycle + 8W)
Data sources and limits
- Power station specs (capacity, output, surge, solar input, weight, cycle ratings) come from manufacturer-published figures.
- Appliance wattages are typical values. Your appliance may differ, so check its label or measure it with a plug-in watt meter.
- Temperature, battery age, and how full the station is charged all change real runtime.
- We don't list prices or ratings. Check Amazon or the manufacturer for current pricing.
How this site makes money
As an Amazon Associate I earn from qualifying purchases. If you buy through a link here, the price is the same for you. Recommendations come from the calculator's spec matching, not from which product pays more.