Supereri73 wrote:
I can run a second ground from the far side and use that for the Shunt/Load- . Running the cable will be easy.
Would 1/0 be big enough for say 100 amp load?
To be clear on terminology, you don't want a second ground. The "far side" pair of batts will not have a frame ground near to them. They will be grounded to the frame as part of the four-battery bank, and the ground for that will be via the shunt's load side (the end away from the battery) to the frame, over by the "near side" pair of batts.
I think 1/0 would do (probably overkill) for the 8 ft parallel links between the pairs, but others might have other opinions on that.
The "near side" pair of batts will be a busy area, having nearby your inverter, solar controller, maybe a deck mount converter, Trimetric shunt, and positive and negative buss bars for all the wires. Also a battery cut off switch if you want one.