Just the thought of using a fossil fuel (mythological) to power an electric car is falls into one of two categories for the electric car owners: Ewww that is like eating a still- beating heart, or.. yeah, I do it when no one is looking in a town far away.
It would be a petty inefficient use of a gallon of gas to charge an electric ca with a generator.
That same generator and gallon of gas can pump gas into dozens of cars if its powering a gas pump.