commercial fast charging isn't that much cheaper than gas.
I could be wrong as I have no experience charging an electric vehicle, but my understanding was that it was far cheaper to charge an electric car battery than it is to fill a tank of gas. Talking like $3.50 vs. $60 (both rough estimates, the exact numbers themselves aren't the point, and we can look them up if needed) for full charge vs. full tank.
Maybe I'm wrong, and the "commercial" bit in there makes a big difference (as it usually does).