Keeping the cable runs as short as possible will let you size the
cables the smallest. Short runs means less problems and easier
installation. Measure the lengths and compute the cable sizes closely. It matters!
It's hard to say much else with more details.
Charging system should be toally reviewed to make sure you have proper
charging. Poor charging will trash those new
batteries quickly. Establishing a good ground is also another issue. Techniques for attachment and connections are another are. There really are a lot of ways to screw this job up. We could also back all the way up and start with a discussion of how you have compted your
power demand and load requirements. In some ways every
installation is different for a lot of reasons.
I would say we have a lot of members that can really help you but of course asking questions will be the first hurdle. You can search gthe fprum for a lot of really good
electrical discussions.