I'll side with Larry here. I see two possible reasons the house battery(s) won't hold a charge. (I'm assuming you're talking going dead while parked and unoccupied?) First the battery may have been deeply discharged (it seems) and has a issue with holding a charge long enough to be of much use. Next the constant small drains on the battery combined with the lowered capacity of the battery causes it to go dead quickly. Here's a link to some videos on batteries and maintenance tips
I'll assume you're the original owner? If not and the battery was replaced with an ordinary car or truck battery, that will be a continuous problem, as a car battery is designed to give a massive burst of amperage to crank a vehicle, not supply a constant demand of power that your house battery should. If it's not a sufficiently rated amp/hour battery for your rig, even if it is a deep cycle battery, that can also be a problem as the load overwhelms a lesser output battery. You'll have to find that info from your rig's manual.