I have a similar question/situation
I just bought a 2016 Jayco Seismic Wave 310 with a generator that came with 1 battery, but they say you can put 6 in the battery area. It would be 2 rows of 3, not 100% sure best way to put in a 2nd row since there isn't 2 level shelves.
This is the battery: http://www.atbatt.com/interstate-srm-27-12v-deep-cycle-marine-rv-battery.asp
Would you stick with this battery and just get more of them, if so how many would you recommend?
If i didn't go with the exact same Interstate battery, what specs should I stick with on the other batteries to keep from causing any problems?
I'm just looking for advice on what batteries to add and how many. I would use them as a backup to the generator and short periods of time when I don't fire up the generator, unless it's better to just fire up the generator even for short periods of use.