Calculator

Backup power calculator

Size a generator or battery for the things you need to keep running in an outage.

What you need to run	Running watts	Starting watts	Hours
Item 1	Running watts	Starting watts	Hours
Item 2	Running watts	Starting watts	Hours
Item 3	Running watts	Starting watts	Hours
Item 4	Running watts	Starting watts	Hours
Item 5	Running watts	Starting watts	Hours
Item 6	Running watts	Starting watts	Hours

Inverter efficiency %Usable battery %

0 Wrunning at once

0 Wpeak, with the biggest start-up

0 Whenergy for the hours you set

0 Whbattery to buy, after losses

Choose a generator or power station rated above the peak watts. Battery size allows for 85% inverter efficiency and 80% usable capacity. Check each appliance's label for its watts.

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