Well I'm going to buy 2 6 volt Trojan T-105's and are going to wire them for 12 volt operation.
I also have 2 under warranty Interstate deep cycle 12 volt batteries (Group 27) that are bad.
I wouldnt mind having that kind of power on the rig. Especially since the Interstates are almost new, they're not great for operating the rig (that's why I want the Trojans) but I think for backup/extra lighting and what not they would be a valuable asset!
What I want to do is have all four batteries, I want the Trojan Bank and the Interstate bank seperate so they won't try to charge one another in case the interstate go bad again.
I'm going to make a new battery box and to keep the banks seperate and charging evenly I was going to get a battery isolator... Is that the hardware I need to do this correctly and most important safely?
I have a generator, 4 solar panels( not installed yet ), and of course the 120 volt shore and the truck charging. I was giong to hook all of those up to the battery isolator input and am hoping the isolator will charge the bank that needs charging or cut off the charge automatically when full???
I did a rough sketch of what I'm planning, I hope this helps give you an idea...
I really want YOUR ideas if you would, I want to make sure I'm doing this right and have the correct understanding of the workings of an isolator...

http://jandhsellhomes.com/graphics/Trailer/IMG2.jpg
Thank you and I can't wait to hear back from you all with your ideas and concerns!
- Jason