0.11 galons per hour PLUS electricity for the pump seems excessive to me. My car consumes 0.8L per hour when it is idling (0.2 gal) and it produces its own electricity, keeps battery charged etc...
Never switching the car off would make about 10L per day.
Something like this to heat the car and charge a lot of batteries would be a better option in my opinion.
https://www.aliexpress.com/item/Dies...0-308ec9f8615f