Originally Posted by larryo
Thank you. Now that I think of it, besides the a/c, HW heater and the wall plugs, most of the systems in the trailer are 12v.
Actually, your WH also requires 12v as well as your fridge. Both can run on electricity or propane, however, the control board, thermostat, and pilots require 12v. The thermostat that controls your A/C also requires 12v.
About the only things in your rig that can operate without 12v would be your microwave, outlets, and possibly TV (some rigs have 12v TV's). Understandably, your converter and battery bank are crucial even when plugged in to shore power.
It's not at all a dumb question. We've all been "new".