[Ggg]

There are s few different ways to run dual batteries. There are pros and cons to all of them. I run my dual batteries in parallel which gives me 12v but double the amperes. I do not run a battery switch or isolator, they perform like one large battery, and it is very simple as in the KISS principal. No special alternator wiring either.
I am not trying to say one method is better than another. Also to get into the science of the pros and cons is beyond the scope of what I want to discuss here.