Originally Posted by pattersonb
I've got one battery in my Cardinal 30RKLE (650 cold cranking amps - deep cell).
This sounds like an auto battery, cold cranking amps are generally for starting engines and do not necessarily provide for continued draw as you find in a travel trailer.
You also state that you usually have electric hookups, which stands to reason why this battery has performed well for you.
If you are going to dry camp, two deep cell RV batteries are recommended as minimum equipment, however, those serious to dry camping have changed to either two or four 6 volt trojan batteries as their design is to provide continuous power draw.
Two RV batteries will work fine if you have a generator to recharge them when needed.