Will It Run Lab

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Power Station Sizing Calculator

For EIA’s 70 W most-used refrigerator average over eight hours, 8 × 70 ÷ 0.85 ≈ 658.8 Wh, which this calculator rounds up to 659 Wh. That energy budget does not replace the starting-watt check: Honda lists 192 W running and 1,200 W starting for an ENERGY STAR refrigerator or freezer.

Required Wh ≈ (sum of running watts × hours × quantity) ÷ inverter efficiency, then rounded up to a whole watt-hour. Starting, one at a time = running total + the largest extra start (start − run).

Default efficiency is 0.85, a planning assumption used on this site when a maker does not publish one. Do not add the EIA average and the Honda running watts as two fridge energy lines unless you really mean to count both.

Size energy and check starting watts

The default line is EIA’s 70 W refrigerator average for eight hours at 0.85 efficiency, which rounds up to 659 Wh. Add Honda start/run rows for the inverter check. This is an energy budget and a published-spec watt check, not a purchase recommendation or a lab test.

Loads and hours of use

Average presets default to 8 hours, a planning window you can change. Honda start/run rows and running-watt presets default to 1 hour so a running figure is not treated as a full-day average. Set hours to 0 to use a row only for the starting-watt check.

EIA most-used refrigerator, 70 W average

EIA 2020 RECS Table CE5.3b, revised March 2024. 617 kWh/year ÷ 8,760 × 1,000 ≈ 70 W. This is a day-long average, not starting watts.

The Honda fridge button adds the cited 192 W running / 1,200 W starting row with hours set to 0, so it does not add a second fridge energy line next to the EIA average. Raise the hours if you want that running figure in the energy budget.

Efficiency and optional station comparison

Default efficiency is 0.85, a planning assumption used on this site when a maker does not publish one. Required watt-hours are rounded up to a whole number. Passing a watt or capacity check is not a guarantee of a motor start. A DC or USB path has different losses; set efficiency to 1 only if you are deliberately omitting the inverter factor.

Compare published power-station specs (optional)
Example stations, not recommendations

Published specs, not recommendations or tests. Select rows to compare capacity and watt limits. These source links are not affiliate links.

1,070 Wh; 1,500 W continuous; 3,000 W instantaneous. Jackery Explorer 1000 V2 basic information.

1,024 Wh; 1,800 W continuous; 2,700 W surge. EcoFlow DELTA 2 US product page.

1,152 Wh; 1,800 W continuous; 2,700 W surge. BLUETTI AC180 US product page.

1,056 Wh; 1,800 W continuous; 2,400 W SurgePad. Anker SOLIX C1000 US product page.

SurgePad is a maker label, not automatically a motor-start rating. Do not count it as verified startup capacity.

Your sizing estimate

Required battery energy
Check inputs
Energy before rounding
Check inputs
Running watts, if on together
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Starting, one at a time
Check inputs
Starting, all at once
Check inputs

Watt totals assume the selected loads can be on together, even when hours of use are lower. If starting watts are blank, they are treated as equal to running watts, so no extra start is invented. Required watt-hours are rounded up to a whole number, matching the battery runtime calculator.

Inputs stay in this page’s URL, not an account. Copying a link shares load names and numbers. Do not include private or medical details.

Worked example: 659 Wh, plus a 1,200 W start

EIA’s 2020 RECS Table CE5.3b gives the most-used refrigerator figure used by the default load: 617 kWh/year, or 617 ÷ 8,760 × 1,000 ≈ 70 W average.

  • Energy at the fridge: 70 W × 8 h = 560 Wh.
  • Energy at the battery: 560 ÷ 0.85 ≈ 658.8 Wh, rounded up to 659 Wh. The battery runtime calculator uses the same rounding when you ask for required capacity.
  • Starting-watt check, from Honda: 192 W running and 1,200 W starting. If that fridge is the only load, one-at-a-time starting is 192 + (1,200 − 192) = 1,200 W.

Leave the Honda row’s hours at 0 if you only want that starting check beside the EIA energy line. If you instead use 192 W for eight hours, the energy total becomes 192 × 8 ÷ 0.85 ≈ 1,807 Wh, which is a different, more severe assumption, not the default example.

Optional published-spec comparisons use the 1 kWh-class capacities already cited on this site, such as 1,070 Wh, 1,024 Wh, 1,152 Wh, and 1,056 Wh. Those figures are published ratings, not usable-energy measurements and not recommendations.

Energy and starting watts are separate checks

A pack can have enough watt-hours and still fail to start a compressor, or start the compressor and run out of energy in a few hours. Use this calculator for both checks on the same list, or split the work: energy here or in the battery runtime tool, and a load-by-load watt check in the generator and power station wattage calculator.

The 0.85 factor is an assumption, not a measured efficiency for every station. Cold, aging, reserved capacity, and inverter overhead at low load all reduce what you can actually use. For a stricter runtime illustration that includes depth of discharge and a standby allowance, see the battery runtime calculator’s optional AC180-form check. Prefer the maker’s formula when it covers your load.

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Sources for presets and example stations

Frequently asked questions

How many watt-hours do I need for eight hours on a refrigerator?

At EIA’s 70 W most-used refrigerator average and the default 0.85 efficiency, required watt-hours ≈ 8 × 70 ÷ 0.85 ≈ 658.8 Wh, which this calculator rounds up to 659 Wh. That is an energy budget, not a purchase recommendation and not a test of your fridge. The inverter must still handle the compressor start.

Why isn’t Honda’s 192 W running figure used for the default energy total?

Honda’s 192 W figure is a running-watt estimate while the compressor is on, not a day-long or eight-hour average. Using 192 W × 8 hours would overstate a typical cycling fridge. The default energy line uses EIA’s 70 W average. Add the Honda 192 W / 1,200 W row, with hours at 0 if you only want the starting-watt check.

If a published 1,000 Wh-class station shows PASS, will it run my loads?

Not necessarily. A PASS only means the published watt-hour capacity or watt limit is at least as large as the calculated need. Surge duration, voltage, temperature, battery age, reserved capacity, and the appliance itself still matter. The Anker SurgePad figure is a maker label, not automatically a motor-start rating. Check the nameplate and the station manual.