Charging

Discussion in 'Technical' started by wolfheads, Apr 17, 2020.

  1. wolfheads

    wolfheads MadMav

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    I tested the volts on my 73 Maverick 302 and the results are this:
    Battery,(motor off): 12.68
    Battery, (motor running): 12.36
    Battery,(motor running and radiator fan on: 12.13
    Battery,(motor running, fan on and lights on): 11.98
    Tested the alternator output: 12.35
    I replaced the voltage regulator. Does it point to a bad alternator ?

    Any input is appreciated, Thanks
     
  2. Acornridgeman

    Acornridgeman MCCI Wisconsin State Rep Moderator Supporting Member

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    I have had many "right out of the box", voltage regulators that fail. You might just have a bad one. They are not all made to work with the old charging systems. And I saw from your other post that the ALT light is now on after changing out the VR - another indication you may have a bad or incompatible one.

    First thing I would do is check the wiring over, make sure everything is hooked back up right. Was the old VR pulled because it was old or because it was bad? If you just changed it out so there was a new one, put the old one back in and see if it is now charging. Engine running you want to see closer to, 13.5 to almost 14 volts.
    If you don't have access to a known, working VR, you might want to test your alternator before trying a new VR. If you are able, pull the alternator out and have it tested. Most auto parts store can do this for free. If you need to buy a new VR - get a good one. I have had my best results with higher end solid state ones.

    I did a tech article on how to make a new solid state unit look like the old Autolite ones. You might find this interesting - http://mmb.maverick.to/resources/solid-state-voltage-regulator-w-vintage-autolite-cover.173/
     
  3. wolfheads

    wolfheads MadMav

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    Yeah, I noticed the alt light on after installing the new VR I still have the old one. I'll swap it out and see if the dash light goes out and re-check the volts.
    Thanks
     
  4. Doug

    Doug Member

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    A few years back I had issue with my Maverick . The light would barely glow and my lights would flicker . Sometimes my battery would be dead . I replaced everything and still no change . then a guy told me my voltage regulator had a bad ground . Fastne a ground wire to it and that fixed my problem
     
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  5. wolfheads

    wolfheads MadMav

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    I reinstalled the old VR and the alt light went out.
     
  6. mojo

    mojo "Everett"- Senior Citizen Supporting Member

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    Regardless of what regulator, you should see close to 14V engine running, If system is charging properly.
     
  7. Acornridgeman

    Acornridgeman MCCI Wisconsin State Rep Moderator Supporting Member

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    Cool ....... what is the voltage reading now at the battery with engine running high idle?
     
  8. wolfheads

    wolfheads MadMav

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    With the engine running at high idle, and the fan and lights on, still at 11.98
     
  9. Acornridgeman

    Acornridgeman MCCI Wisconsin State Rep Moderator Supporting Member

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    Time to test the alternator - like I mentioned - most parts places will do it for free.

    If you want to check it yourself with a multimeter - here is a DIY run down I pulled from a different posting on the web.

    Check for battery voltage at the back of the alternator. It will be the fat wire. If no voltage at alternator then check for burned fuse link near starter relay.

    If that's okay then start the engine. With your meter hooked to the battery use a jumper wire from the battery positive post to the "F' (field) terminal at the alternator. It should have an F stamped on the alternator case. Briefly touch the F terminal. If the voltage increases the alternator is good and the regulator is probably bad. If not the alternator is likely bad.
     
    Last edited: Apr 17, 2020
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  10. Krazy Comet

    Krazy Comet Tom

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    There is a fuseable link in the harness from alt batt terminal at point where it connects to solenoid. If battery or jumper cables have been connected in reverse it's burned out. Result, no charge.
     
  11. Acornridgeman

    Acornridgeman MCCI Wisconsin State Rep Moderator Supporting Member

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    Yes, that test procedure I listed for him tells how to test that link. :thumbs2:
     
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  12. wolfheads

    wolfheads MadMav

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    I took the car to Advance and they checked the voltage. The battery was fully charged but the Alternator was only putting out 12.15 with nothing on. With lights and fan on: 11.98
     
  13. Acornridgeman

    Acornridgeman MCCI Wisconsin State Rep Moderator Supporting Member

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    Did they actually test the alternator for output? Or just tell you what battery voltage was?
     
  14. wolfheads

    wolfheads MadMav

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    The device they used actually diagnosed the charging system and gave a printout of what the battery and the alternator were doing separately.
     
  15. Acornridgeman

    Acornridgeman MCCI Wisconsin State Rep Moderator Supporting Member

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    Nice

    So what was the final verdict? Bad alternator or defective VR?
     

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