Battery gauge going crazy? Alternator?!

[Dan_T_Mustang]

So today I was driving along and everything was fine, pulled up to my destination and rolled both windows up and the battery light on the dash flickers and all dash lights in general dim a little every so often when another accessory is being turned on or off, after the car wouldn't start but after 5 mins it decides to start right up. Lastly the battery gauge moves around when anything is turned on or off as well.

What are possible explanations for this? My first thought was a faulty alternator.

P.S. battery is only a couple months old if that means anything.

 

[ryclef331]

sounds like an alternator to me. Get a hold of a voltmeter and check the voltage with the car running. if you turn on ALL accessories...like radio, a/c on high, head lights on high, wipers, etc....whats the car gauge do. Check you voltage. You can take it to a parts store to test it but I can't even comment on how many alternators I've seen people claim as "Ok" when they're bad.

 

[Dan_T_Mustang]

With everything off, the battery gauge doesn't move at all and everything appears as it should.

 

[CC'S95GT]

still could be the volt regulator inside the alt.
Hook up you DVM to the battery. set it to read DC (duh). you should be seeing @ 14.5 vdc +/-.5. Rev the car to see if the volts change, now start turning on you accessories.
The alt output may drop momentarily but it should come back to 14.5.
If not you need to remove it and take it in to be tested again to double ck.

 

[Dan_T_Mustang]

Just brought it to a shop, they diagnosed it to be the alternator so got that replaced, everything seems to be good but the battery gauge still twitches when a lot of accessories are being used or turned on, it was never like this a month ago, ANYONE have some insight into this?

Thanks,

 

[ttocs]

You probably just didn't pay enough attention to them to be honest. I have a HO alt and at idle I can see the voltage dip on the gauge when the windows are working, heck even the turn signals. A little bit of wobble is normal but for nothing else I would check yer ground/power connections, they should not move at all....