You should check out what type of converter your trailer is equipped with--that is how your batteries are charged. The shore power goes to the converter, where 120voltage is converted to 12 volts for the batteries. If the new batteries required a lot of water, then probably the converter is not the 3-stage type--just a continual charger when on shore power. Check this converter situation out--when you figure out the brand/model, go to mfg website for manual and explanation of operation/troubleshooting.
2016 Tiffin 40 QBH
2015 38RSSA, traded
2005 TK3 #1869, 10 yrs of memories,
2017 F450 KR--one more Ford is it
2009 F450 4x4-died; 2010 F450-retired