we do it all the time.i have an inexpensive 1000 watt inverter that i clip to the truck battery and run an extension cord to a smart charger,clip to the battery bank and charge away.this spring i got a winch quick connect that i use.i unplug the winch and plug in the inverter now. it also charges the boat batteries.its not efficient gas wise,but waaay cheaper than a generator.we also picked up a go power portable solar charger 2 weeks ago.haven't used it yet.i should have hard wired the inverter,but i have nowhere to mount it.