3rd Alternator in less than a year ??

[Screw]

2006 V6 mustang , on Alt #4 in approx 2 yrs . Aftermarket stero , no amps , had stereo installed at so called professional shop . Alternator was replaced by an Auto electric shop in Newmarket . First alt was done before the stereo , and they have all been re manufactured units .Any thoughts from the gurus ?

[ZR]

Not common on that car.
Has it had the battery go flat / boosted n run without charging the battery?
Has it been used to boost other vehicles from time to time?
On am start, does it act like the battery just has enough juice to start the engine?

[Screw]

No boosting of other vehicles , has been boosted instead of charged , battery also replaced within the year . Remote start ...could a load of stereo on ,fan for heat or defrost on at start up affect amp draw ? I know I personally turn everything off on my truck before I shut er down , doubt he does .

[ZR]

has been boosted instead of charged

So batt has gone dead?
If the battery is partially discharging overnight, puts a large load on the alt for an extended period of time bringing it back up to full charge. Rest of the stuff, not really a huge factor unless he's prone to over using high fan and is constantly using the defroster while driving (cycling it on till if goes off / repeating).

[Screw]

Yes battery has gone dead , was boosted to try to get it going , till we discovered the alt . The first time I replaced it I just boosted it and did not charge before I fired it up .

[ZR]

Usually take repeated flat n boosted to kill.
Feel it comes down to
-alt's rebuilt sub standard
-draw overnight, causes alt to constantly be overworked bringing batt back up to full charge
-engine and or body ground issue.

Just because it starts and runs does not mean there isn't a poor ground somewhere.

[Screw]

10-4 , hopefully he finds something , if not .... shop of ZR ?

[ZR]

Best to pull the engine ground off and clean, same for the body ground.
Just holler.

[Screw]

So back from the shop , jr drives locally notices lights dimming so heads home , rests at bottom of driveway . Auto electric shop re re alternator, said cleaned up grounds . Put sct on and monitor voltage , restarts at 14v and drops to about 11 , lights dimming under revs and sparks shoot out of alt ... ?

[ZR]

Alt is fubar.
What did they find with the old one?