People sometimes ask, and I have been wondering myself, how much am I actually spending on electricity for my electric truck. I have made some estimates but it would be nice to actually measure it. I do not have a separate meter for my truck, but I do have historical usage data for my house back to 2007. See the chart below:
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As you can see, I have a very predictable and repeatable low point in my electric usage in the May billing and the November billing (the month number are the billing, usage was from the prior month). These low points in usage are due to the spring and fall times of year when I am not using air conditioning or heating at my house. I consider this to be my baseline usage, excluding heating and cooling. For 2011 in month 11, you can see that the usage is about 5-6 kWh above the level for the prior years (2007 being an outlier for some reason). And I see a similar thing for 2012 month 5, again about 5-6 kWh above the baseline. And I confirm this by looking at the actual numbers in the spreadsheet, not just estimating from the chart.
This is very consistent with my charing pattern. My normal daily commute requires about 2 hours of charging per day and I have a 3 kW charger, thus I use 6 kWh per day to charge.
As for the cost of charging ... If I look at my electricity cost divided by the usage, I see that I pay around 0.11-0.12 per kWh (depends on the total usage for the month - there are billing tiers). By the way I use Austin Energy Green Choice batch 6.
This roughly works out to $0.70 per day or about $22 per month in electricity to drive my truck.