Originally Posted by ApresVanagon
Could this be a house battery problem --like time for a new one?
I agree with Greg above but if you do not have a reliable digital readout of your house battery at all times you should consider remedying that first. A simple power point plug in will do, not scientific accuracy but gives you your batteries state at a glance. I would not have any camper, or honestly even any vehicle without one anymore since I use everything I own for travel and work.
You need to have a pretty accurate idea of where your voltage will be in different circumstances using your van. This goes for both chassis and house batteries. Knowing these patterns will help you the entire time you own it.
-ignition off, vehicle cold should be around 12.8 for a strong battery, less than 12.3 or so and you have a dying battery or a short
- ignition on chassis battery should be about 13.4-14.2, your house battery should match this too after isolator has connected (a minute or two after you start the van)
-house battery while plugged in to power should be the same as vehicle running, around 13.4-14.2
- vehicle running while using inverter you could see drops to 12.5 or so, lower than that and your inverter will start beeping low voltage
- vehicle OFF running inverter I do not recommend ever, I think the appliances we use inverters for (microwaves, kitchen applicances) are too hard on a battery bank for no good reason. So easy to start the van and provide full voltage while using them