Wattstanding

Calculator

Appliance load and runtime calculator

Choose the appliances you want to keep running and for how many hours. We total the watts, work out the battery energy and list the power stations and generators in our catalog that cover it.

typical 150 W, 600 W to start
typical 100 W, 400 W to start
typical 800 W, 1,500 W to start
typical 1,000 W, 2,100 W to start
typical 750 W, 1,500 W to start
typical 600 W, 1,800 W to start
typical 70 W
typical 300 W
typical 25 W
typical 100 W
typical 100 W
typical 60 W
typical 40 W
typical 75 W, 150 W to start
typical 1,500 W
typical 900 W
typical 550 W, 1,100 W to start
typical 500 W, 1,300 W to start
typical 1,500 W
typical 3,500 W, 10,500 W to start
A night is about 12; a day, 24; a long storm, 72 or more

How the calculator works

  • Running watts = the sum of each appliance's typical running watts × quantity.
  • Starting watts = running total + the largest single starting surge (starting − running watts) from any one appliance, assuming motors do not all start at the same instant.
  • Average draw = running watts × duty cycle, because refrigerators and pumps cycle on and off.
  • Battery energy = average draw × hours ÷ 0.85 (inverter and conversion losses).
  • A station qualifies when its capacity covers the energy, its AC output covers the running watts and its surge covers the starting watts.
SafetyAppliance wattages here are typical planning values, not measurements. Read the nameplate on your own appliances. Medical equipment needs guidance from the device maker and your prescriber. Never connect a generator or battery to a home's wiring without a licensed electrician.

For the reasoning behind these steps read how many watts you need for a power outage and how we calculate runtime.

Questions

Why do you ask for starting watts?
Motors and compressors briefly draw several times their running watts when they start. A power station or generator that covers the running total can still shut down if it cannot cover that surge.
Why does a refrigerator use less energy than its running watts suggest?
Its compressor runs only part of the time. We use a 40% duty cycle for a modern refrigerator as a planning figure; your own refrigerator, kitchen temperature and door openings change this.