Battery not charging while running

Electrical & Ignition

  1. Rchab

    Rchab Member

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    Hello,
    I have been restoring my dad's 1969 charger and have come across a big problem which is the battery is not charging when it is running. The car had the later 70 and up electronic ignition which i switched back to the original points ignition setup. My question is am I missing something that runs from the alternator to the battery? I get full battery voltage at the alternator through the green field wire when the key is on but the engine off. Nothing on the output post has voltage however (i don't know if it is supposed to or not). Any help at all would be appreciated as I am stumped at this point.

    20201029_193214.jpg 20201029_193243.jpg 20201029_210908.jpg
     
  2. 493 Mike

    493 Mike FBBO Gold Member FBBO Gold Member

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    The field wire should be blue at the regulator and the alternator. Trace the wire back to the regulator from the alternator to confirm continuity. Did you replace the alternator during the electronic to point style ignition? Electronic ignition is recommended to be used with electronic voltage regulation.
    Mike
     
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    • Rchab

      Rchab Member

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      The wire going from the alternator to the regulator is green. I am still using the same alternator that my dad had put in it. Are there different alternators for the different systems?
       
    • Nacho-RT74

      Nacho-RT74 FBBO Gold Member FBBO Gold Member

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      incorrect, the field wire must be just green on pre 70 alt/reg system with single field alts. On 70 and laters there is one blue and one green to feed both prongs on dual field alternators
       
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      • Nacho-RT74

        Nacho-RT74 FBBO Gold Member FBBO Gold Member

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        948965-5938513311a44f6fa9179e189fe5c28d.jpg

        by the way is the alt field there you got a dual field alt ( 2 prongs ) on a round back alternator, just used on 70/71 cars originally. These are both isolated from chassis, where on older systems needs one chassis grounded

        Ground one of the prongs ( any of them ) and you'll be good.

        One way to make is replace the isolation washer of one of the prongs with a metallic one. Bend or clip off the prong to save from wire it with the green wire because if you plug it there incorrectly will short out.

        OR use a terminal and a jumper wire to feed the extra prong with any ground around ( could use same brush/prong retaining screw )

        YOU COULD also upgrade to electronic regulator with that alt, and will get a more efficient charging system. Just need the elect regulator, the plug with pigtail, couple of splices on the pigtail and one blue wire between reg and the extra alt prong and done
         
        Last edited: Oct 30, 2020
      • Dennis H

        Dennis H FBBO Gold Member FBBO Gold Member

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      • Nacho-RT74

        Nacho-RT74 FBBO Gold Member FBBO Gold Member

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        if the alt you have looks like this with this squared hole on right

        art_18086.jpg

        you could remove the prong/brush and isolator on the left and install the older brush to fill the square hole on the right, and will be te perfect match fot your 69 using the correct brush


        and will look like this, now with the yellow circle empty buth the ground brush provision filled

        index-php-action-dlattach-topic-95028-jpg.jpg

        The brush you would need to fill the propper location is the one on bottom on this pic

        2084673.jpg


        but that's just if that alt got both provisions ( for single and dual field system )
         
        Last edited: Oct 30, 2020
      • 66Satellite47

        66Satellite47 FBBO Gold Member FBBO Gold Member

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        Nacho is correct, if you have a two prong field alt and a pre '70 voltage regulator, the single field wire is green, the second field wire needs to be grounded. Mine is a jumper from the second field spade to the alt case.
         
      • Nacho-RT74

        Nacho-RT74 FBBO Gold Member FBBO Gold Member

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        LOL, just found one of my diagrams signed by another website LOL

        This would be to make the single to dual field alt system upgrade

        mopar_alternator_wiring_diagram_me_at_1.jpg

        and this would be the reg and plug to be used

        1805.jpg
         
      • 66Satellite47

        66Satellite47 FBBO Gold Member FBBO Gold Member

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        That's to use the '70 & later voltage regulator with a '69 single field alt.
        If you have the late model volt reg, be sure the reg case is really well grounded.Scrape the paint off the firewall where it's screwed in and the regulator case. Bad ground there drove me crazy in 1971.
         
      • Rchab

        Rchab Member

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        Just got home and started messing with the car. When it is running at idle I get around 13v at the green wire at the alternator and once I Rev it higher I was reaching almost 20. So if I ground out the other field terminal it will correct it and charge the battery? Because I had 12.5v before I revved the engine and 12.1-2 after
         
      • Rchab

        Rchab Member

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        I grounded the second field to the alternator case and no change

        20201030_165121.jpg
         
      • Rchab

        Rchab Member

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        Come to find the wire running from the ammeter to the output on the alternator was disconnected at the bulkhead. We now have 13+ volts at the battery. My question now is the ammeter went far negative when I gave it throttle. Is this correct?
         
      • 493 Mike

        493 Mike FBBO Gold Member FBBO Gold Member

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        I have forgotten more than I know.
        Mike
         
      • Nacho-RT74

        Nacho-RT74 FBBO Gold Member FBBO Gold Member

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        Wires are reversed on ammeter.

        is correct you will have full reading on ammeter for sometime untill get the battery fully charged back, when must be most of the time on 0 ( as far is posible ). The time you'll get full reading on amm will depend on the time the car was working without an alt keeping it sourced ( which it means battery being discharged ). The more time the batt was sucked, the more time the alt will keep charging it back.

        Wire disconnected at bulkhead... becarefull because a loosen conection can make to burn the area due an overheat, even more with a discharged batt and alt trying to charging back. Loosen conections creates resistance and that causes heat.

        Please check WHY or HOW the wire got disconnected on bulkhead. Make a further check on engine wiring plug. That shouldn't happen and if happened is because there is something wrong there.

        Lot to talk here about this, but later. I'm laid on bed yet LOL.

        ( just edited a bit adding more info )
         
        Last edited: Oct 31, 2020
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        • Nacho-RT74

          Nacho-RT74 FBBO Gold Member FBBO Gold Member

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          BTW!!! while you didn't have an alt "working" you should have an amm reading getting discharge... on this case with reversed wires on ammeter reading would show actually Charge of course
           
        • Rchab

          Rchab Member

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          The bulkhead does show signs of it being melted a little around the ammeter wire connection, I even noticed that when I first began work on the car. This apparently happened before my dad stripped the car down to a rolling chassis 27 years ago (long story). The wires running to the dash should be connected correctly as my red wire runs to the post on the back that has "red" embossed on the cluster underneath it.
           
        • Nacho-RT74

          Nacho-RT74 FBBO Gold Member FBBO Gold Member

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          the melting deal is tipical on Mopars being driven under some circunstances but the first one is a poor capacity alternator used from factory. The connection can be restored AND upgraded with a parallel path between alt to ammeter through the firewall.

          fix that poor conection first then the rest. Bulkhead conectors are available new repro around and is not a hard job, just need patiente. Both ones, the firewall piece and the harnesses pieces

          Having an alt able to feed everything at iddle, will save from lot of troubles.

          Having any accesory correctly sourced from alt side NOT THE BATTERRY, will save from more troubles on charging system. It was a tipical mistake made along the years feeding accesories from batt having an ammeter in line.

          Ammeter should be checked too. There are LOT of threads where we talk about, some of them in the last 2 or 3 months.

          NOW... have the reading reversed could be two of this circunstances:
          -reversed wiring somewhere on the charging system, not just at ammeter, but also bulkhead ?

          and

          A HEAVY SHORT INTO THE ALT. Rotor, Stator... something being accidentally grounded ? dunno.
           
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