Build your backup plan.
Energy tells you how long. Watts tell you what will run. Check both before choosing a station.
Updated · Typical inputs, editable throughout · No hands-on testing
Your devices
Tap a preset to add a row. Published typical watts, fridge surge and duty; hours and other duty values are planning assumptions. Replace them with your device label or measurements.
Your assumptions
When off, only one individual device marked “can schedule separately” runs at a time; all other devices remain concurrent. Hours and daily energy do not change. Verify that this schedule is possible.
Idle draw is battery-side W and assumes the inverter stays on all day. Zero means idle draw is omitted, not that your station has none. Solar derate and sun hours are user assumptions, not local forecasts.
Does an example station fit?
These are specification checks, not a complete market ranking or a compatibility guarantee. Startup duration, waveform, port limits and regional voltage still matter. Unknown device surge inputs remain unverified even if a row passes.
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What is inside the estimate?
Daily Wh = Σ(quantity × W × hours × duty)
Battery Wh = (daily Wh ÷ efficiency + idle W × daily hours) × days ÷ usable fraction
Reserve is the portion left unused. Surge is the largest single startup event with the other concurrent devices running; simultaneous motor starts are not modelled. Duty reduces energy, not continuous or startup W.
OutdoorGearLab reports 60–93% of advertised capacity as usable AC energy in its tests. That is their research, not ours, and does not validate this calculator’s efficiency assumption for any particular model.
Full methodology and limitationsPrint-ready buying checklist
- Replace typical watts with your device label or meter readings.
- Confirm actual startup W and required surge duration.
- Check each port, local voltage and frequency, and required adapters.
- Check solar open-circuit voltage, current, polarity and connector limits.
- Plan a recharge route for poor weather.
- Confirm any medical-device backup with its equipment provider.
- Never back-feed home wiring. Use a qualified electrician for circuit integration.