I've recently noticed the voltage gauge reading under 13.5 volts while driving around.

Just this morning when I switched on the car the battery was reading 12.4 volts and when I turn the car on the voltage gauge remained at 12.4 for a few minutes before going up to 13.2.

I would think the alternator would go up to 13.8 or 14.2 since the starting battery voltage was so low. That's how it seemed to be in the past.

This is all with the radio on and air conditioning going.

Battery is about a year old.

Currently on a trip so I don't have a voltmeter with me and I'll stop at O'Reilly's to have them test it.

Wondering what other people think. Thanks in advance.