Here I ga again posting stuff from a Sailing book but why reinvent the wheel .
Many long term sailors have already worked out many of the issues that can come up in a school bus .
Sailboats can find themselves in some rather isolated spots so have learned to setup their equipment correctly to hopefully avoid serious problem's .
Monthly Maintenance: All Charged Up | Cruising World
there are many articles there also on wiring requirements crimp-on vs solder how to chose which batteries sizing estimates dealing with diesel motors gen-sets .