How Many KWh to Charge the Volt?

[greencar]

I am one of the Volt CAB drivers and thought I could answer a question that has come up a few times on this website. The Volt does not tell you how many kWh are used in the EV mode, but I have a dedicated TOU meter for the Volt charger so I can measure the amount of kWh’s used to charge the vehicle. As an example, during my trip to the electric car meet up in Montclair, NJ yesterday, I drove 110.2 miles total and 44.5 were in EV mode and 65.7 using the gas generator. I burned 1.6 gallons of gas during the trip. But, to answer the kWh question, when I charged the car at home in the evening, the car took 12 kWh of electricty to charge the depleted battery.

[ColinSummers]

It looks like it would have cost me $0.72 to fill your tank that night.

In the last twelve months I spent an average of $68 per month of fuel for the Prius. Seems like it will be hard to spend that much on electricity for the Volt.

Now I have to figure out whether it would make more sense to route my solar generation through the EV meter rather than the house meter (both TOU).

[honoreitiscom]

I drove 110.2 miles total and 44.5 were in EV mode and 65.7 using the gas generator. I burned 1.6 gallons of gas during the trip. the car took 12 kWh of electricty to charge the depleted battery.

Assuming the national average of $0.12 per kWh electricity and $3.00/gallon of premium gas, you went 13.7 miles per dollar of gas and 30.9 miles per dollar of electricity.

(I pay $0.0986 per kWh, so I would have gone 37.7 miles per dollar of electricity)

[WopOnTour]

Your charging efficiency of ~86% perhaps is a bit lower than expected but not excessively so.
Your TOU device, is it a smart meter or some sort of accessory at the breaker?
What is its resolution? (ie was it 12, 12.0, 12.00 kwh? )
WopOnTour

[hermperez]

Your charging efficiency of ~86% perhaps is a bit lower than expected but not excessively so.

Very typical of chargers and power supplies.

[honoreitiscom]

Robert Becker: Can you please report what the temperature was on the night that it took 12 kWh to charge the battery? Just wondering if there was much battery conditioning going on. Also, did you pre-condition the cabin temp on grid power before you unplugged? These things could explain some of the power draw, which would indicate a higher than ~86% charging efficiency.

[MVRacing]

....which would indicate a higher than ~68% charging efficiency.

~86% was stated

[honoreitiscom]

Oops, good catch. I edited my post to say 86%.

[greencar]

Robert Becker: Can you please report what the temperature was on the night that it took 12 kWh to charge the battery? Just wondering if there was much battery conditioning going on. Also, did you pre-condition the cabin temp on grid power before you unplugged? These things could explain some of the power draw, which would indicate a higher than ~68% charging efficiency.

The car was parked in my garage all night while it was charged. The garage is probably around 50 degrees although I did not measure the temperature. I did not precondition the cabin temperature on grid power before unplugging.

[George S. Bower]

Robert,
It would be interesting to know how efficient the 110V charger is. Maybe you could use it one night as a comparison.