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Joined: Thu Aug 09, 2018 11:46 pm

kWh Usage on 120V

Thu Sep 06, 2018 2:35 pm

I am trying to understand kWh usage/cost on my Clarity PHEV at home using 120V. If it takes 6 hours to charge the battery to capacity am I using 6 kWh, or is this to simplified and there is some other factor I need to consider. Here in Southern Calif with Edison TOU plan I pay 13 cents a kWh between 10PM and 8AM. So with the above figure 6X13= 78 cents, sounds to good to be true.

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Joined: Mon Mar 26, 2018 5:22 pm
Location: Arcadia, CA USA

Re: kWh Usage on 120V

Thu Sep 06, 2018 7:32 pm

There is slight loss due to inefficiency in the conversion process, (I think less loss in level 2 charging that we are using). But you can log into your online SCE account and kind of look at how much is being used, hour by hour. If you do not charge one night, then charge the next, you can approximate your usage based on subtracting the difference. I log in almost every day to check our bill. (I put us on TOU-D-A because the letter we got advised us this was the cheapest option for our usage, we were net metering before that).

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Joined: Sat Jan 13, 2018 5:28 pm

Re: kWh Usage on 120V

Fri Sep 07, 2018 3:17 am

The charge cord included with the clarity will charge at 12A and 120V. The equates to 1.44kW, so 1 hour of charging will use 1.44kWh. Very roughly 90% of that will actually make it into the battery. There is less of a "taper" with L1 charging, but as the battery gets full, charging will slow (the charger is built into the car and controls how much power is drawn).

So a good rule of thumb is 1.44 x $0.13 per hour of charging or about 19 cents per hour. 6 hours of charging would be ~$1.12
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Joined: Thu Aug 09, 2018 11:46 pm

Re: kWh Usage on 120V

Mon Sep 10, 2018 2:15 pm

Thanks for the replies very helpful

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Joined: Sun Sep 02, 2018 4:51 pm

Re: kWh Usage on 120V

Thu Sep 13, 2018 12:57 am

Hi Glen,
Seems a bit low.
My So Cal Edison TOU -D-1 has the following rates (per the SCE Website):

Tier 1: Peak (12pm - 6pm): $0.37/kwh
and Off-Peak: $0.19/kwh

Tier 2: Peak: $0.42
Off-Peak: $0.23

Not sure if we are comparing apples to apples, but it is still superior to gas. At the $0.19 rate, it works out to about $0.05/mile. As you know, we are approaching $4.00/gal out here, so $2.50 for 50 miles feels good (unless I made a math error).

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