My 2008 trailer came with a ELIXIR Mdl ELX-30 SIngle Mode converter which I replaced WFCO 8900 Power Distribution Center with a WF8945 Smart Mode Converter and it never read anything except 13.6VDC everytime I measured it at the batteries. I eventually changed Just the CONVERTER UNIT out for PD9260C Converter/charger unit. This unit goes into the smart charging modes just fine.
I leave my trailers plugged into 120VAC from the Garage 20AMP receptacle using an adapter all the time here with no battery issues. I do check the battery on a regular basis for setting charge status and also check the battery fluids.
If i didn't have smart mode charging available I would disconnect the battery when parked. If the batteries have a good charge on them they will not freeze up during the cold weather periods. If they drain down to ZERO charge state they will freeze up inside and bust the battery walls...
Same thing will happen to your truck start battery. I would check it for charge status as well and never let it get below 50% charge state while sitting.
Roy Ken
