Tried this while in Hawaii with a rental EV (with no charging at my hotel) and it did not work at all. Hawaii is one of the states with the most EV's per person and there's frequently chargers in places like malls and grocery stores (whole foods and target in particular). However, because there's so many EV's, all of these chargers are always in use, and there are usually lines or people waiting around to snag a spot as soon as it becomes available. It was a massive inconvenience and put me off of EVs for the near future: I'd either need an sfh or to be somewhere that figures out public charging when more than a tiny fraction of the total vehicles on the road are electric.