I am an electrical novice. I am working setting up a dual-battery system for my 80.
I know Scott is using the Sure Power Isolator:
Boston Mangler is using his super simple and cheap method. I like his method due to the simplicity. (attachment)
There is also the Hell Roaring system. Which I like b/c you can control the unit from the cab.
Then...there is the Ibs Dual Battery System that TJM makes. The unit appears to be fairly simple to my feable mind. You can also monitor both batteries via the LED lights (a bonus for weirdo like me). BUT this unit is rather expensive.
Lastly there is the Power-Gate by Mobi Arc. There is no moving parts (?) and very little loss of power. These guys are local, and I have been meaning to go and talk to them. Just haven't yet.
Basically, I am looking for assistance from all the other electrical gurus here that know a lot more than me. My knowledge is limited, but growing...slowly.