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Alternator going out?

Discussion in 'VY Holden Commodore (2002 - 2004)' started by vongy10, Apr 1, 2019.

  1. vongy10

    vongy10 Active Member

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    Hi all,

    I drove to work on friday, car started fine got to work no problem. Left work after about 30mins and the battery was dead. Had it jump started with a battery pack, went to get groceries and car started fine.

    Went back to work the same night, started car, drove to work, no issues. Finished work after 5hrs and it's dead again. Tried to jump it and it was a no go (wouldn't crank over at all), checked the battery's indicator and it said 'take to dealer' so I assume it was toast. Borrowed a brand new battery and car started and drove fine for a day and a half.

    Was going to head to work last night and car was dead again. I haven't done any electrical work on the car in about a year so AFAIK there's nothing draining the battery. So only thing left I can think of is a faulty alternator and the car has been running straight from the battery without charging which is probably what killed the previous one.
     
    Last edited: Apr 1, 2019
  2. accentstencil

    accentstencil Well-Known Member

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    The best thing to do is measure the voltage at the battery with the engine running, it should be around 14.4 volts, anything much less than that means that the alternator is not charging. That it to an auto electrician to test if you don't have a multimeter.
     
  3. vongy10

    vongy10 Active Member

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    Tested the battery on charge with car off, read around 14.6v then tested with car on and it was reading around 15v, finally with the car off with not charger it's resting voltage is around 13.7v not sure how accurate my multimeter is though since the numbers kept jumping around.
     
  4. Lex

    Lex Well-Known Member

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    Sounds like a faulty regulator in the alternator?
     
  5. vongy10

    vongy10 Active Member

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    Yeah. I'm now thinking that too. I pulled the negative terminal off the battery while the car was running and it didn't stall so yeah I dunno.
     
  6. vc commodore

    vc commodore Well-Known Member

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    I'd be looking at the regulator.....With the car running, the alternator output should be 14.4 to 14.6 volts.....Jumping upto 15V to me sounds like the regulator isn't working properly, allowing too much voltage through to the battery and probably cooking it
     
  7. Deuce

    Deuce Super Stock

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    How many km's on car/alt?
    Over 200k and the brushes on slip ring might be too worn. This can sometimes appear like reg issue when in fact the reg is fine.
     
  8. krusing

    krusing Active Member

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    I have repaired a few over the years, replacing the brushes on the Regulator, Replace the Bearings etc, etc,
    But if you not sure how to repair them, easier to just get a change-over, then its all done for you,
    And you get a warranty.
     
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  9. vongy10

    vongy10 Active Member

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    Car has 48K on it. Thanks for all the replies, may as well change it out for a new one since it's a pain to get it out especially now that I've got a snail on the side. Hoping it fixes the issue.

    Also, gave the prevoius battery to my dad and he somehow got it back into the green although we haven't tested it.
     
  10. vc commodore

    vc commodore Well-Known Member

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    Judging by this comment, yes your alternator regulator was giving you the issues.....so changing over the complete alternator/regulator would be the best solution
     
  11. axemurderer101

    axemurderer101 Well-Known Member

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    Do a current draw test on the battery (google it if you dont know how) something could be draining your battery.
     
  12. vongy10

    vongy10 Active Member

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    Got a new alternator in but am having a little trouble getting 2 of the 3 bolts in. The 2 outer bolts for the bracket only go in about 1cm before I can't tighten them by hand anymore (even without the alternator in). Can get the middle bolt in fine, tried the middle bolt in the outer threads too and it can only go in about 1cm too. Did I f!ck up the threads? I don't want to force the bolts in since it's an aluminum block.
     
  13. accentstencil

    accentstencil Well-Known Member

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    If you got them in about 1cm before they became hard to turn then I doubt that you stuffed the thread. Cross-threading usually occurs at the first couple of turns.
     
  14. vongy10

    vongy10 Active Member

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    Just ran a thread taper through in case, got the new one in. On initial startup it was reading between 14.5-14.8v. Took it for a drive and tested again and it was in the low 14v range. I will have to test it again tomorrow. Battery itself reads around 13.5v when the car is off.
     
  15. delcowizzid

    delcowizzid on holiday

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    Never disconnect the battery with the car running it kills the diodes in the alternator and spikes all the electronics with dirty high voltage spikes
     
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  16. vongy10

    vongy10 Active Member

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    FFS, drove to work, finished, went to start car and it was dead again. Time to take it to a sparky...
     
  17. Rory_

    Rory_ New Member

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    Let us know how you go, hope you found assistance
     
  18. BowTie

    BowTie Active Member

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    Maybe intermittent short in alternator or starter wiring.

    Multimeter on a charged battery will show current flow in amps to the short.
     

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