Battery light now on in my 328. Did the sound shop damage the alternator? | FerrariChat
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Battery light now on in my 328. Did the sound shop damage the alternator?

Discussion in 'Technical Q&A' started by DMaury, Jun 9, 2007.

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  1. DMaury

    DMaury Formula 3

    Mar 27, 2007
    1,993
    Ponchatoula, LA
    #1 DMaury, Jun 9, 2007
    Here’s the story.

    I took the 328 in to Baton Rouge to have the radio and speakers replaced as well as get the antenna working. The prior owner had two aftermarket amps and a rats-nest of wires all under the seats ad there were shorts everywhere.

    The shop did a great job of cleaning all that out, and replacing everything. It all works and sounds great. However, the battery was near dead when I went to pick the car up this afternoon. (They had been running the radio from it and hadn’t recharged it yet). I had them jump the car off, and started to drive it back to my house 30 miles away. The battery light was on, but I assumed that this was just because the battery was very low and it would go off once the alternator charged it up to a suitable point.
    Well, the car made it a few blocks and died. Luckily, it died in a residential neighborhood with a teenager working on his Camaro on the corner. He ran over, and jumped me off twice. Each time the car killed a few seconds after the jumper cables were disconnected. I called the sound shop, had them come pick me up, went to Napa, bought a new battery and plopped it in. The car started up fine then, and everything worked, except that battery light stayed on. It was not doing this prior to taking it in to the sound shop.

    I didn’t feel comfortable trying to drive it 30 miles with that light on, as I fear I am running the car on battery power alone and the alternator is not working.
    My question is, is there anything that the people at the sound shop could have done to damage the alternator? All they did was disconnect and reattach the battery cables.
    The car is being towed back to my house as I type, so I will be able to check it out in my garage in an hour or so.

    I would appreciate any tips.

    Thanks.

    Maury
     
  2. eurogt4

    eurogt4 Karting

    Apr 15, 2006
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    Sacramento, CA
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    Mike
    #2 eurogt4, Jun 9, 2007
    The alternator is not designed the charge a dead battery, just to maintain a full charge when running. The alternator will probably have to be rebuilt. Check the belt just to make sure it is in good condition.
    Mike
     
  3. DMaury

    DMaury Formula 3

    Mar 27, 2007
    1,993
    Ponchatoula, LA
    #3 DMaury, Jun 9, 2007
    Yes, that's what I figured when it died. But after the new, fully charged battery was put in, the battery light stays on. The car runs fine, but I'm sure the alternator isn't working. The thing is, it was before going to the radio shop.
     
  4. Steve King

    Steve King F1 Rookie

    Feb 15, 2001
    4,367
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    #4 Steve King, Jun 9, 2007
    I would think whenthe either were working on the car or when they jumped it the crossed the wires and shorted out a diode in the alternator or blew th regulator. Just put a volt meter on the battery and start it up. it should be running at 13.6 to 14.2 volts and if not the regulator is toast.
     
  5. miketuason

    miketuason F1 World Champ
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    Feb 24, 2006
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    #5 miketuason, Jun 9, 2007
    Yes, it could be just your voltage regulator but just the same you still have to remove your alternator
     
  6. DMaury

    DMaury Formula 3

    Mar 27, 2007
    1,993
    Ponchatoula, LA
    #6 DMaury, Jun 10, 2007
    Problem solved. Retard here didn't even want to post this, but I figured I better stand up and take my medicine. ;)

    The problem was, well, it's kind of hard for the alternator to charge the battery when it's not TURNING! The belt had snapped and was gone! I didn't even think to look while I was in town. I got the car home, popped the engine lid and went DOHH!!!!!!!

    It’s working great NOW, don't ya know! ;)
     
  7. f355spider

    f355spider F1 World Champ
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    May 29, 2001
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    #7 f355spider, Jun 10, 2007
    You have a spare in your tool kit too! ;)
     
  8. DMaury

    DMaury Formula 3

    Mar 27, 2007
    1,993
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    #8 DMaury, Jun 10, 2007
    Oh yes, I knew that one already! That's where the belt came from so fast. :p
     
  9. spiderseeker

    spiderseeker Formula 3

    Jul 22, 2005
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    #9 spiderseeker, Jun 10, 2007
    You solved the problem !!! No need to be embarrassed about it, we've all missed obvious fixes, be happy and go for a long drive and enjoy !!
     
  10. miketuason

    miketuason F1 World Champ
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    #10 miketuason, Jun 10, 2007
    The good side is, it made you bought a new battery but I'm glad it's fix now.
     
  11. KENCO

    KENCO Formula 3

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    #11 KENCO, Jun 11, 2007
    So the problem turned out to be , just a loose nut behind the wheel?
     
  12. DMaury

    DMaury Formula 3

    Mar 27, 2007
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    #12 DMaury, Jun 11, 2007

    LOL! You got it! It seems that's usuallly the case with me. ;)
     
  13. BigTex

    BigTex Seven Time F1 World Champ
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    #13 BigTex, Jun 11, 2007
    You have a later car obviously, when my alternator belt breaks it stops turning the water pump as well and ALL the guages tell ya something's WRONG!

    Glad you got it sorted........

    The dash light is actually monitoring a relay on the charging system, it'll be off as long as charge from alternator is greater than load, and comes on when the alternator is not producing current and the battery is draining..

    Easy to understand once you know that.
     
  14. DMaury

    DMaury Formula 3

    Mar 27, 2007
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    #14 DMaury, Jun 11, 2007
    Well, I had it brought down to Jim Lindsey today for a belt service and a thorough going-through, so we'll see what else he finds that needs to be done. :)
     
  15. BigTex

    BigTex Seven Time F1 World Champ
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    #15 BigTex, Jun 12, 2007
    Ahh, it's in good hands now then ..........congrats!
     
  16. Mike328

    Mike328 F1 Rookie

    Oct 19, 2002
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    #16 Mike328, Jun 12, 2007
    Happy this ended "well!" By the way, just to be clear, the "Battery" light is not a battery light but an "Alternator" light (or "generator light" in some documentation). It does not show the condition of the battery - it shows the condition of the alternator (the charging system).

    So it's not surprising, given that your alternator was not turning, that the alternator light stayed on even when you put in a fresh battery. There needs to be output from the alternator (charging the battery) for that light to go off.

    What I'm confused about is, that light should have gone on the moment the alternator belt snapped...

    Also, is it coincidence that the belt snapped right after this service?

    Or, does a very low battery, by putting more of a demand on the alternator, actually put more of a load on the engine / requiring more force to turn the pulley hence stressing the belt more?
     
  17. 330gt

    330gt Formula 3

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    #17 330gt, Jun 12, 2007
    Yes, a low battery (either from lack of charging or drained by a hard start) will cause the alternator to run at full output (~50 amps). This puts a higher load on the belt. Typically a loose belt will squeal for a couple of minutes after starting while the alternator recharges the battery. Then the load decreases and the belt stops squealing. And the owner ignores the situation. Eventually the belt fails.

    So it is quite possible that the drained battery caused the alternator to load the belt enough to break it if it was already in poor shape.
     
  18. DMaury

    DMaury Formula 3

    Mar 27, 2007
    1,993
    Ponchatoula, LA
    #18 DMaury, Jun 12, 2007
    You just perfecty described what the car had been doing for about two weeks before. I believe this is what happened now.
     

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