Make the jump and install a second battery. If you need a new one I would go with 6 Volt batteries. Had 6 volt in motor homes but trailers always come with 12V.
I have added a second battery in every trailer we have owned. Needed if you run the furnace for a weekend when dry camping.
I have this set up in our fifth wheel - it is a battery box designed for 6 volt batteries. Put some styrofoam pieces in it to prevent movement of the batteries. Just in case - - - 12 Volt are connected in parallel and 6 volt will be connected in series.
