Thanks guys. I just didn’t want to return to batteries plus and have them ask me what makes you think the battery is bad? Now I have some knowledge to stand my ground.
Less is more… Just say you charge it overnight, 30 min later, the voltage drops to 10v. .
They’ll most likely throw it on a battery tester which will say good or bad and then warranty from there
FYI, it has one dead cell. Remember that a 12V Pb battery is made of 6 cells each of ~2.1V so when you see ~10V on a Pb battery one of the ~2V cells is 0V. A battery load tester will show this quickly since it’s really what you are doing by charging and driving just a little bit.