An over-night cabin heating system is used for campers. A system that can be turned on and off as you please.
A heating system in a camper while traveling around the (sometimes very cold) island will definitely come in handy, whether you will only use the heather to heat the car before you go to sleep or perhaps to keep it running through the night if the system allows it.
The motors system is connected to the main fuel tank and to a secondary battery. It differs if the systems run on one or two batteries but most do run on two so they can be left on for hours.