I get this question a lot but the answer is a bit tricky when, in theory, it should be very simple. Tricky because people are normally used to filling up their gas tanks only when they’re near empty, so they end up paying more or less the same amount of money, aside from fluctuations of gas prices. EV owners, on the other hand, follow a different habit. We plug in every night, regardless of the current state of charge. Therefore, the amount we pay on each “fill up” depends on how much we drove that day. We very rarely get home “empty”, and we normally don’t charge to 100%, but to 80% instead, in order to extend battery life. So “empty-to-full” almost never happens so cost estimates are normally theoretical: we know how much the battery can hold, multiplied by the electricity costs, so we will throw a rough number at you.
Last week, I decided to answer this question using hard numbers, so I went to my records to try to find one of those days where I charged to full (or near full) from near empty. Based on the report we get from our smart meter, the charger draws 3.8 KW of power during charge (i.e., 3.8 kWh per hour). The longest continuous charge I found on record was 5.2 hours, from completely depleted (turtle mode) to 11 bars (out of 12). At the end of the charge, the car dashboard estimated I still had one hour to go to get to 100%. So in total, 6.2 hours of charge would have drawn 23.56 kWh . We pay 12.8 cents per kWh off-peak, according to our hydro bill. That includes electricity cost, delivery, taxes, debt retirement and rebates. So that full charge would cost $3.01.
That was the day where I drove 125 Km on a full charge, as part of a cold temperature range experiment (temperature was -10C), so that trip only cost us 3 dollars. For comparison, making the same trip with our second car (a Corolla, doing about 10 liters/100 Km in the winter) would have cost us $15.83, or 425% more.
So there you have it: $3 dollars to fill it up. Or the equivalent of 2.4 liters of gas. But I still don’t think that means much to a regular car owner. Because EVs have to “fill up” every day, right? Yes, but no… What really hits them is when I say “it is as if I were buying gas for less than 24 cents a liter, while you’re paying $1.25.” 🙂