(PART 1)
Interesting,
I leave the SOLAR running 24/7/365 and very seldom need to replenish any water. Is there a chance that you may have a battery with a bad cell? Top off your batteries and then I would at the end of a sunny day (batteries should be fully charged) disconnect all the batteries from each other, shut down the SOLAR connections and pull the main fuse that goes to the TT and let them rest (independent of each other) for at least 24 hours. Ideally, you would then check each cell's SG, if at all possible. If not, get a piece of paper and take the voltage readings of each of your batteries. I have the batteries marked 1..2 with a indelible marker, so I can make sure I am documenting the correct battery (memory is not what it used to be).
Don