Just for comparison I completely disconnect my battery bank on my Starcraft 14 R/T setup which has three 85AH Batteries for my battery bank.
When i quit running the trails in early December I will leave the batteries sitting on my tongue but they are completely disconnected with my Blue Sea Switches. I am usually reading 12.6-7VDC on my battery monitor panel with no DC CURRENT being drawn. I usually keep tabs on thing just out of habit and will watch the battery DC VOLTS just sitting there disconnected...
It very slowly starts dropping off on DC VOLTS and by MARCH when I want to start heading for the woods again they will be down to the 12.4 VDC level. When I see this I will hookup my shore power and start my on-board PD0260C charging again...
It does get down into freezing temps here in VA but had zero problems with my batteries sitting on my trailer tongue all winter long. They do not freeze over if they are holding a decent charge level...
Been doing this since around early 2009 and after loosing one of my four 85AH Interstate batteries early from boiling out fluids due to trying to charge with a single 30A single mode 13.6VDC ELIXIR converter/Charger unit. After I replaced the ELIXIR with the Progressive Dynamics Converter/Charger Smart Mode 60A setup all have been just fine ever since. I still check the fluids levels ever couple of weeks out of habit however...

Roy's image
My three 85AH Interstate started to not holding their their charge state in 2015 and I finally had to stop using them. I am just now getting to the point of building up a new battery bank using two paralleled groups of Duracell 6V 230Ah batteries wired in series. this should give my a big 460AHs 12VDC battery capacity.
Hopefully I will be back on the OFF-ROAD camping trail this season...
Roy Ken