Battery Won't Stay Charged

Discussion in 'Technical' started by Krax, Nov 30, 2010.

  1. Krax

    Krax Member

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    I have a brand new alternator and battery, but it just won't keep the battery charged. It's hooked up right, and it's making me mad cause I thought I fixed it but I guess not, anybody know what could be the cause of that?
     
  2. Acornridgeman

    Acornridgeman MCCI Wisconsin State Rep Moderator Supporting Member

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    What is the charging voltage at 1500 rpm? Should be between 13.8 and 14.2 volts. If that is OK - your new battery might have a bad cell. If lower than 13.8, you have issues with the voltage regulator, alternator, or wiring for those 2 items.

    Test the voltage and post back.

    :thumbs2:
     
  3. 65 comet

    65 comet Member

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    :hmmm: Do you know if there is a short that is drawing on the battery? Check the draw buy disconnecting + cable and use a multimeter between cable and post. Is the Regulator good? Jump start car and see what voltage and amperage is being put to the battery. You can check Alternator buy starting car and removing cable from battery, see if it will keep running on just Alternator output. If not have it checked, could be defective. If you can, do a draw down test on battery to see how fast and well it recovers, it may be bad. even new stuff can be defective. Good luck. :tiphat:
     
    Last edited: Nov 30, 2010
  4. Krax

    Krax Member

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    It might be the voltage regulator, gotta wait til my roommate gets home so i can ask where his testers at
     
  5. smegnl

    smegnl Roger Saffle Supporting Member

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  6. Krax

    Krax Member

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    If I take off either connection to the battery it dies... Good thing I got a lifetime warranty on my alternator. Ima check all that other stuff too.
     
  7. Acornridgeman

    Acornridgeman MCCI Wisconsin State Rep Moderator Supporting Member

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    That pretty much tells you where to look ......... :thumbs2:
     
  8. PaulS

    PaulS Member extrordiare

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    Disconnecting the alternator with your engine running is not a test for an alternator.
    They used to test generators that way but all it does with an alternator is spike the voltage to over 90 volts. It can ruin the alternator, regulator and most electronics in your car.

    There are specific tests that you can, and should, run to diagnose charging problems.
     

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