As long as you are not driving a piece of crap it will be fine. If the cars electrical system is operating normally then yyou should not have any issues. Just don't leave the car running with the keys in it without someone watching it. Otherwise you might come back and it will be by by

. There are a lot of mean people and wierdos in the world.

If you plan to make a habit of using your car as a power source for your RC charging you might want to take a fully charged spare car battery with just in case it does get drained. A little preplanning would be a good thing.