[Brad Townsend]

I have a feeling all is well with your solenoid. The best thing you can do is leave it on while plugged into shore power that way you get both banks charged. I have been told by an industrial engineer that it is best to leave things like this on, it is the on and off that weakens it similar to incadesent bulbs which would last longer if just left on. I sometimes merge my batteries here in the desert just to keep them up and close to the house batteries. Both banks are the same type and age so this is a good thing. My opinion! It wouldn't hurt to check the difference of voltage on either side as recommended by Russ.

Brad