I have used https://www.scootorlando.com/scooter-reservations/ Their ECV last all day and then some. Mine lasted 2 day with out a charge and if you rent from them for 3 or more days they offer a discount.
I don’t have firsthand experience with this but I do know that there are tons of threads on TP and other places (like the DISboards) about many different aspects of scooter usage at Disney. So you might be able to search and find more answers, maybe even to questions you didn’t know to ask.
Exactly, no sense in not being able to enjoy it!