# Interest group forums > Electrical Contracting Industry Forum > Electrical Load Shedding Forum >  battery calculator for inverters

## Tonye

Hi all, so, weré back to load shedding.  :Mad: 

I have been asked so many times by clients, how long will my batteries last on my inverter.

So I have made an online battery calculator.

Based on 80% inverter efficiency & 50% depth of discharge on the batteries. (these are default settings on the calculator and can be changed.

The calculator is responsive, so will work on mobile phones and can be saved to your home screen.

View here https://bit.ly/2Uc8l55

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