Just remember, if you decide to run your system off of one battery and then switch to the other and then decide to charge them together, the batteries will not be at the same level. You may have used one battery down to 12.0 and the other only down to 12.5, so one battery will require less of a charge than the other, and the charging system will look at the average of the 2 and one will be under charged, or possibly one overcharged. Constantly charging them in this manor will lessen the batteries life.
Not sure as to why some people want to use 2 separate batteries opposed to 2 combined? Either way you have the same amount of Ah’s available.
2013 Jayco Eagle 284BHS
250Watt Grape Solar Panel, MorningStar MPPT 60 Charge Controller
1500 Watt Ramsond PSI, 2 Trojan T145 Batteries (260Ah)
2 - AirSight Wireless IP Cameras (used as rear view cameras)
EnGenius WI-FI extender, D-Link wireless (n) modem
MagicJack Internet Phone
2012 Ford F150XLT, EcoBoost w/3.73
157" Wheel base, HD Towing Package
Our Solar Album http://www.jaycoowners.com/album.php?albumid=329