Voltage Regulator and Battery Charging Issues

Discussion in 'Troubleshooting & Diagnosis' started by Bowtie Performance, Dec 30, 2016.

  1. Bowtie Performance

    Bowtie Performance New Member

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    I have been trying to diagnose a charging issue on my 71 for weeks now. The battery will show 12.6V when the car is off then drop to around 11.8 when the car is running. I'm assuming this means the alternator is not charging the battery. I got the old alternator checked, it failed so I bought a new one from Napa. Still have the same problem. The number 1 and 2 wires off the alternator go to the old external voltage regulator and the other wire on the alternator goes to the positive battery post on my starter (My battery is in the trunk). Can the voltage regulator cause the alternator not to charge the battery? I recently replaced the radiator core support which the voltage regulator is attached to. Is it possible the regulator is not getting a good ground from the new powder coated core support? Do I need a new regulator? Or can I just remove the regulator and get an internally regulated alternator? Thanks guys, I finally want to get to the bottom of this.
     
  2. Gary S

    Gary S Administrator Lifetime Gold Member

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    The voltage regulator definitely can cause the alternator to not charge the battery. That is what its job is. It controls the alternator charge.
    Yes, if you replaced the radiator core, you could easily have ground problems. Powder coating is deadly to electrical systems working. It is bad news.
    Your regulator could be bad. Did it work before you changed things? If it did, you probably caused the problem yourself with the powder coating.
     
  3. Bowtie Performance

    Bowtie Performance New Member

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    Yep it worked before I changed things. Can I just remove the coating where the regulator is mounted?
     
  4. Z27LS3

    Z27LS3 Veteran Member

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    yes, just a little on the surface to make sure ground and body are "metal to metal".
     
  5. rocket dawg

    rocket dawg Veteran Member

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    For what its worth, I usually get the original rebuilt. I have the original starter on my 406, its been rebuilt once. Alt was dropped off and picked up 20 minutes later all rebuilt as well. Just lucky to have a shop in our area that offers this service and its quite reasonable money wise. Hope you get yours figured out.
     
  6. lapedr

    lapedr Veteran Member Gold Member

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    You could run a jumper wire from the neg battery terminal to the VR to see if its a ground issue before going out and buying one just to discover its not that.
     

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