Alternator Problem

[CyberFyber]

Hello, The basic gist of my question is this:

Is it possible for an alternator to go from 'not so bad' to 'totally bad' overnight?

Reason I ask is this:

The other day we left the lights on in the car and so I had to jumpstart it using an external portable charger. This didn't really go so bad when I did it finally this morning. I surmised for awhile that the battery had to be changed because of age and perhaps because of other problems the car had such as going dead after turning the ignition and then hitting the break to switch to drive. But then it's not until now that I understand how this also might've been a problem with a faulty alternator.

Well, the thing is that this afternoon I took to the shop and they figured it was the alternator AND the battery which needed to be replaced. So I agreed to the battery replacement figuring on thinking over the rest and probably returning in the morning.

Suffice it to say, my car is stranded on the street in the other side of town after literally dying on me on the road....'and it's the the second time since leaving the shop that there's been a problem. I'd never had problems of this magnitude until this week.

So again, is it possible that my alternator really went berserk overnight? or is possible that the shop forgot to reconnect something or other before I left them? (mind you, I'm pretty auto illiterate and such.)

[TheSilentChamber]

Yes.

[Austin8214]

Originally Posted by CyberFyber

So again, is it possible that my alternator really went berserk overnight? or is possible that the shop forgot to reconnect something or other before I left them? (mind you, I'm pretty auto illiterate and such.)

Yes on both counts.

[Rufe]

The battery and alternator work as a team.
Your lights (brake lights going on) could have used the last bit of battery power needed to keep the engine running. If the alternator is bad, the new battery will not last very long before it is discharged also.

I had to replace an alternator once, that seemed to be fine, it put out enough volts at 4000 rpms, but the moment the rpms went below that, it dropped off to nill very rapidly. Around town, the battery wasn't getting any recharging. And it degraded very quickly, but not overnight.

How many miles did you drive with the new battery? What kind of car?

[UncleBob]

if the diode bridge goes out in the alternator, not only will it not have enough juice to keep the battery from draining, the A/C current will play havoc on the battery and can also damage electronic components in the car.

And most alternators die suddenly. Rarely do they give you any warning.

Not sure why you're blaming the shop on this one....they told you the alternator was bad, and you just proved beyond a doubt that its definitely bad. Where did the shop go wrong?