Starter battery connections

[msham87]

I have a 2000 reflection 327 and it has 2-12 volt starting batteries. I am trying to figure out what all the connections to each battery is for.
On one battery, there are 3 heavy duty positive connection (one a cross over to the 2nd battery) and 2 heavy duty negative connection (one a cross over to the 2nd battery).
The other battery has 4 positive connections (one a cross over cable) and the other battery has 5 negative connections (one a cross over cable). Four of the negative connections on this battery are light gauge connectors.

I have tried to trace these but with all the wire harnesses under the RV, it's virtually impossible to trace. Does anyone have any idea what these battery connectors might be for? I am trying to trace a possible voltage leak as the batteries seem to drain themselves after 2-3 weeks of sitting idle.

Any suggestions would be appreciated.