Yesterday we installed 2 450 Amp hours, 6 volt batteries
Good to hear the beeping is stopped.
For the record, 2 - 6v GC2 batteries of the type used in Rvs will produce about 225 AH, not 450. Interstate makes a couple different 6v GC2 batteries, with an AH rating from 210 to 232. When two of them are put in series, the voltage doubles to 12v but the AH remains the same, so a pair has the same AH as a single one.