Battery switching help... Please.

Decent wrench turner here, however mostly electrically disabled!

I have two diesel engines, two batteries and two guest battery switches. Currently, there is no house battery. The DC requirements are run off of the starboard battery. I also have a generator, but it has it's own battery for starting, not attached to the switches. I am NOT confident that the original installer set the system up correctly. There was a repower and some rework done that leads me to believe this. Are there any diagrams that show the PROPER setup for this arrangement? Do I really need two switches?

Thank you for your help! I have other questions, but one at a time, for your sake.

 

They make about a 100 different switches. Please give us a wiring diagram of what you have, including the engine year/make/model and the switch model numbers, and anything else you know about the history of the set-up. There is seldom only one right way to do this. It's normally a compromise between being able to isolate and combine pieces the way you want, and the ability to handle engine problems like being able to work on one safely while the other is running.

It's important to include all charging sources. Do you have shore charger, solar panels, 12V genset with a charging function? We need the specs on these and on the batteries and fuses.

 

You need to draw what you have. The reason for the low response is well laid out by Phil