Are you able to put an amp meter off the battery to determine if you have a current draw pulling the battery down? If not you would disconnect the negative post of battery (after charging) and redo your test to see if it holds better voltages for a longer period.
Mike, RVIA & RVSA Certified Master RV Technician
Amy, Dr. Assistant - Roxie & Mei Ling, four legs each
2000 Gulf Stream Scenic Cruiser 450 hp & 1330# torque
06 Saturn Vue, 06 Chevy Z71 4x4 & 2014 Corvette Z51 M7