# Measuring cost of charging.



## Sue in Cambridge (Aug 9, 2018)

I'll be charging at a Level I outlet which is supplied from an electrical panel that supplies many other outlets in my condo community. Is there a way to measure the electricity I've used for charging my Model 3, cumulative over time, so I can pay them monthly? I'll charge other placs as well, so can't use total mileage. --same question when we get level 2 chargers installed, which will be shared.


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## Klaus-rf (Mar 6, 2019)

You will need a meter on each outlet. Shared is an issue unless evreryone annotates the start/stop values for each charge session.


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## Sue in Cambridge (Aug 9, 2018)

Klaus-rf said:


> You will need a meter on each outlet. Shared is an issue unless evreryone annotates the start/stop values for each charge session.


Is there a way to tell how many KWH have been used in a charge session? I can only find miles added which is pretty different...


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## mrau (Nov 22, 2018)

On a 120v outlet the car will draw 12 amps. The hourly watt draw is volts * amps. So 120v *12amps = 1,440 watts each hour you charge. That is same as 1.4 kW per hour. If your cost per kilowat is 15 cents, then it would cost about 21 cents per hour of charge.

It may be best to estimate how many hours per month you will be plugged in and decide on a flat monthly rate to reimburse.


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