If the batteries are on shore power for long periods they may start boiling out the fluids. I check mine every couple of weeks here...
Having a smart mode charger (that works) will help reduce the possibility of the batteries boiling out on you...
Post your model number of the converter/charger being used...
I am using the Progressive Dynamics PD9260C unit here and do not see any boiling out of fluids when on shore power for long periods of time. Out of habit I still check my batteries just in case...
My batteries lasted good from 2009 to mid 2016 when I have scaled back alot of my camping... I am in the process of upgrading my battery bank now with new batteries and more capacity.
Roy Ken
