I have 10 100w PV's charging four, series connected 12v, 114Ah batteries. I'm using a Victron 150/35 controller set at 48v. The batteries are less than 4 months old and ALL purchased NEW at the same time (two even have sequential serial #'s). Problem is.... the center two batteries (#2 and #3) are charging at approx. .3V higher than the end two batteries (#1 and #4). Swapping the batteries individual position within the string, doesn't change the charge voltages - it's always the center two batteries being over charged at .3V to .4V higher than the end batteries. At rest, all measure 12.85V and all SG's are nearly identical. What's causing this?
edit: All cabling between batteries is 4 ga.
edit: All cabling between batteries is 4 ga.