Originally Posted by STEVEVILL38GT
Batt will charge visible when the truck side is running. I put the inverter on and you can see the volts build to approx 13 + Now withe the Truck side off and With the Gen running or shore power connected you can watch the house batts deplete down the the warning beep 11.2 volts. If I shut off inverter it will not charge our deplete further but House side will operate all appliances/ air con, etc. fridge normally. overnight with appliance off with exception of the air con on. it will stay at the voltage at the time I shut of the inverter. Did check breakers, etc appears all in. Arrrgh.
When your running the "Truck side" the engine alternator is charging your house and the chassis battery, thus looking at the inverter the voltage is in the charge range. If your running from shore or generator the charger of the house batteries should charge the house batteries and in some RVs will also charge the chassis battery, as well as convert AC to DC. You say with the inverter on and connected to AC voltage, the DC voltage decreases, then, the converter/charger is not converting/charging and your inverter is drawing DC to meet the AC demand. If you turn the inverter off then the voltage remains the same overnight then that means overnight you only used 12 volt items(DC) of minimal draw with no AC devices being run.
Not knowing what type of RV you have or what equipment is installed, I can only guess, that your are observing the voltages from some remote panel. For instance on a Magnum Remote you not only have a Inverter button, but also with the Inverter and Charger combined you also have a Charger button which turns the charger on and off. Is the charger button turned off? If you have some kind of other equipment is the 120V AC breaker for the converter(charger) turned off or thrown?
Hope it helps?