@Lynn2137
Are they wanting to use your EV Charger, or are they wanting to use a trickle charger for the battery?
In any case, you need to add information in your Addl House Rules and in the Other Details Section of the Listing to outline your restrictions regarding this for future guests.
Not sure there is anything you can do now without risking a negative review, but you could politely ask the guest to contribute something to the electrical cost?