Have a similar issue.....maybe a new thread? This is very close. Had a pair of 6V in series for twelve for last 18 months. Finally got the 400 watts of solar
tied into the Prostar 30 Mornigstar controller.
Everything was fine for a week. Checked on boat
and both batteries were hot and took close to gallon each (3/4 a allowing for spillage with the distilled water.).
Two days later...same thing. Disconnected solar
and the shore power
charger still had them hot. Shut off shore and the solar seems to keep them up and fine. Used them to start engines after a while of charging
. Disconnected them and read 6.54 V on one and 6.34 on the other. Left them disconnected for two hours and checked charge....no difference. HAve been on solar for two days and no issues so far.
BAtteries? COntroller? Charger? I am guessing controller and charger may be in league here.