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Alternator Not Charging

Discussion in 'Early CJ5 and CJ6 Tech' started by Unkel Dale, Apr 16, 2019.

  1. Apr 16, 2019
    Unkel Dale

    Unkel Dale delivery on my Jeep from Ft. Campbell, Ky.

    Pittsburgh, Pa.
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    replace the three wire Motorola alternator question
    I connected the three wires of the external regulator to the alternator correctly
    what is the grey 18 gauge wire to the dash cluster do? It connects to the idiot light, IS THIS THE EXCITER CIRCIUT? It GETS power from the gauge cluster? Can't I take power from the big lug on the rear of the alternator WITHOUT the light connected at the cluster? I think that that is the correct question

    Question how do I bench test the external regulator? What leads for the tool go where, on what settings?

    Bummer, no answers yet, several readers, thanks

    Photos of oem Motorola three wire rear faces of alternators and Ford Prestolite 4 wire systems from Intermediates please
     
    Last edited: Apr 18, 2019
  2. Apr 19, 2019
    Primer Coat

    Primer Coat New Member

    Ohio
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    Is not a three wire alternator internally regulated?
     
  3. Apr 19, 2019
    Howard Eisenhauer

    Howard Eisenhauer Super Moderator Staff Member Sponsor

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    Usually the idiot light/exciter is from a switched source to prevent battery discharge when the vehicle isn't running. Is the bulb burned out? What lead you to believe your alt was bad & not the regulator?


    Depends on what alternator you're talking about. Early alternators showed up before electronics became small enough & reliable enough to have the regulator incorporated into the alt case.
     
  4. Apr 19, 2019
    Walt Couch

    Walt Couch sidehill Cordele, Ga. Sponsor 2019 Sponsor

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    The Motorola Alt used a solid state external regulator on some models. To test the reg you needed to connect it to a alternator and run it up on a test bench that had a volt and amp meter.
     
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  5. Apr 19, 2019
    Howard Eisenhauer

    Howard Eisenhauer Super Moderator Staff Member Sponsor

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    In theory you could wire the regulator across a battery in a car, non running the field terminal would light a test light, when running the test light would be off or dim.
     
  6. Apr 19, 2019
    55_Willys_CJ5

    55_Willys_CJ5 Nephews Visit 2017 Sponsor 2019 Sponsor

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    The gray wire, as you mentioned, to the dash is the exciter circuit. As Howard stated make sure the light bulb isn't burned out. Make sure the light isn't an LED Bulb . LED doesn't draw enough to "excite" the alternator, when this happens the alternator will not charge. Learned this from experience.

    No, and No. When the ignition key is turned on, the dash "Idiot" light draws power to "Excite" the alternator so that once the engine is running the alternator starts producing electricity. If the alternator doesn't get excited it won't produce electricity.

    Can you post pictures of the back of the alternator and the regulator in your set-up?
     
  7. Apr 19, 2019
    Walt Couch

    Walt Couch sidehill Cordele, Ga. Sponsor 2019 Sponsor

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    In theory yes but your only testing one function of the regulator.
     
  8. Apr 19, 2019
    Howard Eisenhauer

    Howard Eisenhauer Super Moderator Staff Member Sponsor

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    True, but having done some research there doesn't appear to be any such a thing as current limiting on an alternator regulator, at least the solid state ones. :shrug:

    All I can see for current limiting is (occasionally) a 6" piece of 12 gu. wire inserted into the 10 gu. wire going (sometimes eventually) towards the battery.:rolleyes:
     
    Last edited: Apr 19, 2019
  9. Apr 20, 2019
    Unkel Dale

    Unkel Dale delivery on my Jeep from Ft. Campbell, Ky.

    Pittsburgh, Pa.
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    NO Sir, Motorola system OEM for 1966 is externally regulated and had tappets and springs not solid state electronics
     
    Last edited: Apr 20, 2019
  10. Apr 20, 2019
    Unkel Dale

    Unkel Dale delivery on my Jeep from Ft. Campbell, Ky.

    Pittsburgh, Pa.
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    OK now I need to write more here,
    right now there is no grey wire installed, it burned up the wire loom fire,
    there is no light bulb installed in the cluster,
    there is no power connected to the cluster, I never had a fuel gauge in the tank, its a blank, or monitor temperature. I only use the speedometer
    IF I convert to the one wire 12 si alternator, am I done there?
    If I change to the 12 si, does the direction of the rotation matter, the alternator cooling fins look backwards for the 12 si from the Motorola fins behind the drive belt pulley
    thanks for replying Dale
     
  11. Apr 20, 2019
    sterlclan

    sterlclan Member Sponsor

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    no
     
  12. Apr 20, 2019
    Unkel Dale

    Unkel Dale delivery on my Jeep from Ft. Campbell, Ky.

    Pittsburgh, Pa.
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    12 si it is, thanks everyone
     
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  13. Apr 23, 2019
    wasillashack

    wasillashack Member

    Wasilla, Alaska
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    While one wire alternators are popular due to ease of installation, they have a few drawbacks as well. The one wire does not have accurate (if any) voltage sensing, must be self energized by revving the engine at start up, and regulators are not easily found, like 3 wire regulators. This last issue is somewhat lessened by the fact that fewer and fewer parts stores are selling rebuild parts for any alternators. Google "mechanical man" , "Ron Francis" or "12 volt man" for further info. Good luck!
     
  14. May 15, 2019
    71CJ54WD

    71CJ54WD Sponsor Sponsor

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    I did a one wire swap and it’s just wise. Remember it takes really low rpm to start charging with a one wire. If your engine is idling at 900 that alternator pulley is flying. Just run heavy gauge wires and ground. I grounded the battery direct to a starter bolt. Then ran a ground from alternator mount to frame and frame to body. This gives you solid grounds all around and fast cranking along with sufficient charging.
     
  15. May 15, 2019
    timgr

    timgr Jeepin' Nerd Sponsor 2019 Sponsor

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    A '66 should not have an ammeter, but it should have an "Amps" light. If you install a one-wire Delco alternator, I would (1) remove an any aftermarket ammeter if present, (2) install an aftermarket voltmeter, (3) protect the Jeep from fire with fusible links between the ammeter and battery (in that "1-wire"), and between the battery and the dash. The one-wire is going to make way more amps at full charge than the original Motorola, and sending all that power to the dash and back through a potentially dodgy ammeter risks a carbeque. With a 1-wire Delco, you have no amps light capability, so you need something to tell you the conditon of the charging system - hence voltmeter.
     
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  16. May 15, 2019
    45es

    45es Member Sponsor 2019 Sponsor

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    A one wire alternator may be the simplest to install, but in my opinion it is not the wises. It is worth the effort to install a three wire alternator which when installed correctly, monitors the electrical systems load and responds accordingly.
     
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  17. May 15, 2019
    71CJ54WD

    71CJ54WD Sponsor Sponsor

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    Yes this is a good point, however the delta is minimal between the 1 and 3. Running the sense wire to a further load draw on the 3 wire versus installing the charge wire at the solenoid isn't going to make a huge difference on a small Jeep. If you have lots of electrical load that also switches on and off (like seat heaters, window defrosters) then the 3 wire is a notable improvement. But on our Jeeps all we run is a basic ignition system and lights. Some have a winch which draws so much any alternator will know to start charging. I think the wisest install on our little Jeeps come down to what you feel like wiring up because they'll all do the job with ease.
     
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  18. May 16, 2019
    Unkel Dale

    Unkel Dale delivery on my Jeep from Ft. Campbell, Ky.

    Pittsburgh, Pa.
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    OK Tim I'll bite on the Voltmeter idea.... From the Battery with a fuseable link wire on Say 10 Gauge stranded wire TO the Voltmeter... From the Voltmeter mounted in the dash (back to the Battery? with a fuseable link and a 10 gauge wire?
     
  19. May 16, 2019
    Unkel Dale

    Unkel Dale delivery on my Jeep from Ft. Campbell, Ky.

    Pittsburgh, Pa.
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    Yea never figured out the photo thing. The system WAS oem Motorola from 66
     
  20. May 16, 2019
    timgr

    timgr Jeepin' Nerd Sponsor 2019 Sponsor

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    VoltmeterSketch.jpg

    The fusible links protect the Jeep from the battery (fire!) in case of a catastrophic short in the wiring or alternator.
     

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