Problem with alternator

[Naseem]

Hi everyone, so I have been trying to fix this problem for almost a month now. When I tried to start the car, I used the multimeter to check for voltge, the battery gave me 12.2V while engine off, with engine on 11.4V. I knew then that the alternator is bad. I got new alternator still not charging. Then I replaced the 120a ALT fuse and everything started working and the alternator is charging the battery with 14.5V , I let the car for a while just to charge up the battery, turned off and went to sleep feeling happy that I fixed the problem. The next day I went to start the car and battery light turned on. Cheked the battery volts around 11.5-11.7v. What should I do next I’m confused

[VBdenny]

My guess is a bad cell in the battery itself.  

[sha4000]

Yes the old alternator probably damaged the battery.