How to read the result
- Base load — everything you ticked running at once. The inverter size adds 25% headroom on top.
- Peak — the base load plus the biggest single start-up surge. The station's surge rating must be at least this high.
- Capacity comes from the average load: a refrigerator or lights don't run all day, a router does.
Start-up surges
Anything with a motor — refrigerators, freezers, well pumps, furnace blowers — draws 3–4 times its rated power for a second or two when it starts. That's what trips most power stations. Don't start the pump and the refrigerator at the same moment, and choose a station with surge capacity to spare.
Power station or inverter and battery
A portable power station is all in one box — battery, inverter and charger — and works out of the box. An inverter with a separate battery bank usually costs less per Wh and can grow, but needs installing. For an apartment, most people choose a station; for a house with a furnace and well pump, a larger battery system or a generator often makes more sense.
Already have a station? See how long it will run with your devices.
Frequently asked questions
What size power station do I need for a refrigerator?
A refrigerator draws 100–200 W but up to 4× that for a moment when the compressor starts, so the inverter must handle a 600–800 W surge. For an 8-hour outage with a refrigerator, router and a few lights, a 1,000–1,500 Wh station is usually enough.
Will a 1,000 W power station run a well pump?
Usually not. A 750 W well pump can draw 2,000–2,500 W to start. If the station's surge rating is lower, it will shut off from overload. Look at the surge (peak) rating, not just the continuous one.
How many amp-hours of battery do I need?
Divide the energy you need in Wh by the battery voltage. For a 12 V LiFePO4 battery that's 12.8 V: 1,700 Wh ÷ 12.8 ≈ 133 Ah. The planner shows this for each outage length.
What is a pure sine wave and why does it matter?
It's the same smooth voltage the grid delivers. Cheaper inverters output a modified sine wave that can upset furnace electronics and make motors run hot. For a furnace, refrigerator or pump, choose a pure sine wave inverter or station.
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