it only happened once

 

If your battery is at 9 volts in the AM, then its either a current draw or your alternator is not working properly or both.

 

my battery was dead one morning ....I used a totally different tester on it instead of the gauge in the dash twice recently and it reads 14.1 every time but is erratic when I drive. At times it feels like my car is going to die.

 

I'd have the alternator checked thoroughly.

 

if I buy a refurb is that ok or should I buy it new? I’m just going to hv it replaced

 

I've had better luck with rebuilt than new AC Delco.

 

Just to confirm, this was before or after the battery first indicated some issue?