Hi,
I replaced the coach batteries in my new to me 2008 2551 in late January. I went to S&S RV Super Service Center (recommended by Tom Hanlon). George at S&S recommended Astro-Lite Group 27 Deep Discharge Marine batteries (12 volt). He also tested the charging systems both from the vehicle alternator and the Trip Lite Inverter/Charger. I had a very good experience with S&S and would recommend them.
I see that you are in PA, but I don't know how far you are from Gettysburg.
David