On an rv with one or two batteries you will be fine. It is not a great idea to try and charge a bank of batteries on a diesel pusher that has perhaps four 6 volt and two 12 volt batteries. Heavy duty alternators are used on emergency vehicles and decent size ones on large rv's.
I would not be concerned. Idling while parked can be problematic due to air circulation and hot catalytic converters. I used to turn my tow vehicle around and use heavy duty jumper cables to bring the tt batteries up.