I researched Fullriver AGM batteries a few weeks ago as a replacement for two 8-year-old Group 29 100 amp hour 12V Interstate AGM batteries in our Class C motorhome.
I installed two Fullriver Group 31 115 amp hour 12V AGM batteries to replace my Interstates. I chose Fullriver AGM 12V batteries because of their reputation and because of one of their 12V AGM battery specifications ... the specified float voltage of 13.6 volts. This is the same float voltage as was specified for our previous Interstate AGM batteries. I wanted AGM batteries requiring a float voltage equal to the output of our RV's stock 13.6 volt converter so that I wouldn't risk damaging the batteries when in storage with them switched into the RV's 12V system with the converter left turned on for floating. Not all 12 volt AGM batteries have a specified float voltage that matches stock RV converter outputs ... and I saw no reason to not continue using an otherwise perfectly good converter. However, due to the low internal resistance of AGM batteries, when discharged they will also charge up faster from 13.6 volts than wet batteries will ... before being floated on that same 13.6 volts without damage.
Fullriver's reputation seems to be pretty good - expecially in the marine world. But what really sold me on them was the world class marine world reputation of Rolls Surrette batteries. I found out that Rolls Surrette was in fact having the very same Fullriver AGM battery that I bought rebranded (and in a different colored case) for them as a Rolls Surrette model. I figured that if Fullriver was good enough for Rolls Surrette - Fullriver was good enough for me.
Here's the Fullriver battery that I installed two-of:
http://www.fullriverbattery.com/product/batteries/DC115-12
