Having run group 24s like I thing the OP runs,I'm not surprised that it is failing after 2 years. Their capacity was about 80 AH each. I had 4 in the PD (320 AH) and thought I was looking after them well but in retrospect they likely were under charged (not dead, just seldom above 90% for long periods) and I gave up on them after 4 years. I had and have solar charging too that I though was keeping up but probably really wasn't.
I replaced them with 4 GCs, giving me 484 AH. the difference was very noticeable.
Electricity is expensive here in southern Mexico so I charge with solar as much as possible though I do have 120V (more or less, sometimes) but am shaded for much of the day. When it gets to the point that solar won't get the batteries up to 14.4 volts (after about 4or 5 days) I engage the Xantrex Prosine 2.0 inverter/charger according to the manufacturer's recommendation at the 20 hr rate of 96 Amps. 45A should do you fine as long as the charging algorithm is reasonable. (Check with MW on that :B )