You had the truck camper plugged into the house:
Well. Most trailers and motor homes have a device called a Converter. This "Converts" 120vac to battery voltage... I do not know if a "Truck camper" has one of these or not.. if not you may wish to add one I recommend a Progressive Dynamics 9200 most likely the 9245 or 9260 depending on your batteries (Total the C-20 amp hour capacity of yoru batteies and multiply by 0.3 that's the last 2 digits of the model number you wish to match)
Get a "P" model (plugs in, though you may need an adapter since some of them come with 20 amp plugs. ) or request a 15 amp plug.
