So last Thursday I was driving home and as I pulled into my driveway I got a “Battery Saver active” alert and saw my volts running at like 11 something. I took the car the next day amd had it looked at and was told my alternator was bad. Which made sense cause it was knocking, I knew it was before they told me

I just replaced the alternator last night at a friend’s house. I drove 3 miles home and the voltage was 14.4 to 14.7, occasionally 14.8

I started the car up this morning snd drove 7 miles to work. For all but the last mile the battery voltage was at 15.2. Until the last half mile when I stopped at the one red light I drive thru, it dropped down to 13.4 and as I started up driving it slowly got back up to 14.8. As I began parking it got back up to 15. Is this possibly just a bad battery?