http://rollsbattery.com/public/docs/user_manual/Rolls_Battery_Manual.pdfThis manual does not quite say there is a minimum for Wets, just that low and slow will give more of a chance for sulfation to set in. Might not be the same manual as Mex quotes?
Note the 15v charging voltage for 25C/77F that is above Trojan's 14.8 even. Good luck with your standard RV converter. (A PowerMax LK type adjustable voltage one will do it though.)
I don't understand their idea of "gassing voltage" at 2.25/cell (13.5v ) when the usual story has been at 14.2ish. Then they say to Float at 13.5v! Can't be right.