1 charge controller, 2 separate battery banks

swanee98

I have an original setup,  Renogy 60 amp charge controller and 2000w inverter. I bought 3 new batteries 230 ah each, that I thought I could add to my original 220 ah battery,  but was told they're not compatible. I have a larger inverter with the new batteries. 
 My question is whether I can use a marine 3 way switch to isolate each battery bank and how to wire it. I do have some electrical knowledge,  not an expert. The battery banks are in two adjacent cabinets in my motor home.   Can both battery banks share the same neutral buss bar?
 The power from the charge controller, does it need a 3 way switch to each battery bank?
 The battery outputs will go through a 3 way switch. I appreciate your input. 

JRHill

The easy part is the neutral (negative?) buss bar and the answer is Yes, IMHO.

You already bought the 'marine' batteries. And there is a concern about 'compatibility' and there is an easy answer here too. One should never combine batteries that are not IDENTICAL and definitely not of different ages.

Lastly the 3 way switch. Best wishes there. The KISS acronym comes to mind.