Bad battery or bad alternator?

[KDog125]

So on my way out i was driving and i noticed my dash lights slowy get dimmer, then pulling into gym it slowly turned off and car wasnt able to start....no icons on dash such as battery or anything and lights still worked but car wouldnt start...changed alternator about 2 years ago or less, and got a new battery...used another cars battery to get it home and she worked fine...could it be the battery or the alternator that is on its way out? any info would be greatly appreciated...Thanks!

[f550maranello2]

its gotta be the alternator since the car died.. take a volt meter and jump start the car.. put it on the battery.. see if you get 14 volts..

then as the car is running remove the negative cable and measure again (positive to ground obviously) .. if the car dies the alternator is the problem

dont have the battery unhooked with the car running for longer than like a minute

[321VQ35MAX]

Correct. Sounds like alternator. 9 times out of 10 battery will not cause car to shut off, just not to start.

[Maximamisfire]

I bet its the alternator. My car did exactly the same when my alternator died last year.
The headlights were very dim, the airbag light came on, and then it slowly died. And then wouldnt start.
It started a few minutes later, but my tach and speedometer did not work. Was trying to drive it home, and it again slowly sputtered and died. Battery was fine, but alternator was dead.

[romicva]

How would I know if it's starter or battery/alternator?

Thank you.