I added one battery to the existing 12v deep cycle 105ah battery (B) in the tray in my new Jayco Alante 31v immediately but really want to have three or four. So, I added one more using the storage bay adjacent to the battery bay. Due to trying to keep the wires as short as possible, when I added "C" I used 9" 4 awg wires, the same gauge as originals. When I added "A", I had to use 35" 4 awg cables and ended up with the connections you see here.
Although I do not have the solar installed yet, the wires on the far left on "A" are what I plan. I know it is not optimal, but due to space and keeping cabling as short as possible I will use 12" of 6 awg (the max that will fit in the charge controller terminals).
Any issues with how this is all wired, other than not being optimal