I would say when the controller indicated the batteries were full it should have dropped back to 13.49VDC...
It has been my experience that 13.6VDC will boil out your battery fluids over time and the battery should drop to 13.2VDC FLOAT MODE when no current is being commanded.
Be sure to check your fluid levels after a bit. I don't think that would be normal boiling your fluids like that unless it has been sitting at 13.5-6 for a longer period of time.
Also a single solar panel like yours should only be producing around 5AMPS of DC current which is in the neighborhood of trickle charging for batteries.. I would think the battery would not be boiling on you with that low of DC CURRENT. It would take 17-20AMPS at that DC VOLTAGE to boil up some fluids I would think..
maybe some experts will dime in here what might be going on...
Roy Ken
