sunshine_eggo
Happy Breffast!
You're under-charging and your batteries amp hour rating is extremely optimistic and you're grossly under-cycling the batteries.
Charge to 15.2 for around 2 hours and cycle down to at least 11.9 volts. Lower if under moderate to heavy load.
Where are you getting 15.2? Even my Rolls only want 15, which is the highest I've ever seen.
I would hesitate to push lower quality batteries to higher voltages.