There is a constant amperage draw on the battery when the trailer is not in use, CO alarm, propane alarm, entertainment center etc etc.
Make sure battery is fully charged before "parking the trailer" then disconnect the negative battery cable. Then when you have time install a disconnect switch at the battery.
2007 Surveyor SV230 - 200 Watts Solar/MPPT Controller - 230 AH Battery Bank - 600 watt PSW Inverter - (2) 2000 watt Inverter Generators - LED Lighting
2009 F150 - 5.4 Litre - Tow Package
Boon Docking 99% of the time.