Dim Your Bill

03Power stations

Power station runtime calculator

Tick what you'll run, set the hours per day, and enter your power station's capacity and output.

Checked

What you’ll run, and hours per day
UseItemHours/day
Refrigerator (modern, full size)
Wi-Fi router and modem
Two phones charging
LED lights (5 bulbs)
TV (55-inch LED)
Laptop
CPAP (no humidifier)
CPAP with heated humidifier
Chest freezer
Box fan
Microwave (1,000 W cooking)
Coffee maker
Window AC, 8,000 BTU
Sump pump, 1/3 hp
Electric blanket
Space heater (high)

—of backup

Energy per day
—
Highest draw at once
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Output check
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Assumes 85% of the battery is usable after inverter losses. Running watts are typical; check your appliance’s label.

Tips

  • The fridge figure is an average. A compressor runs on and off; we use about 60 W averaged over the day, which matches a modern full-size fridge using about 1.4 kWh a day. Older fridges can use twice that. Your fridge’s yellow EnergyGuide label lists kWh per year: divide by 365 for a daily figure.
  • Heat is expensive. A space heater or a hair dryer empties a 1 kWh battery in under an hour. An electric blanket is the cheap way to stay warm on battery.
  • Check the output limit for things that start with a surge, like pumps, compressors and microwaves. Stagger them rather than starting two at once.