I recently came across an advertisement in an RV magazine ("Roughing it Smoothly"), for Lifeline Batteries. They sound as if they've been specializing in batteries for RV and Marine applications for quite a while.
http://lifelinebatteries.com/products/rv-batteries/
I had never heard ot them before...
Has anybody in here got any experience with their products? They sure sound good: I wonder how they really work?