MAD ELECTRICAL?

Discussion in 'Electrical and Ignition' started by coalman, Aug 27, 2018.

  1. coalman

    coalman Well-Known Member

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    Have any of you done this Amp Meter by pass? If so, looking at their picture of the 16 gage fusible Link coming off the starter relay, are both the Red and Black wires attached to the link, or are they spliced together further down??? Thanks a bunch
     
  2. 67Dart273

    67Dart273 Well-Known Member

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    The way they get re-wired the red and black form a parallel path. This does two things..........the new wiring sends charge current direct to battery, so charging current does not have to go through the bulkhead ammeter. This relieves strain on that wiring. Second, the parallel path means that the red and black, working in parallel, work as one big wire to feed current for the rest of the car.......headlights, heater, etc

    Some guys don't like the way MAD does that and advocate simply jumpering from the alternator direct to the battery. That is OK, too, but it removes the fuse link protection........which is damn poor to start with

    If you do that, I'd add a breaker/ fuse link to the new part of the circuit
     
  3. coalman

    coalman Well-Known Member

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    I tried to call them, I think they leave the phone off the hook for guys like me. So both the red and black wires are spliced into the fusible link, or after further down the wire run? I am also thinking of running a 10 gage wire from the Alternator to the relay with a 14 gauge fusible link like the diagram shows as the 66 has a 12 gauge. Thanks for all your input!!!
     
  4. rklein383

    rklein383 Well-Known Member

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    I did the upgrade as MAD recommends. I also installed relays for my headlamps and for my dual electric fans. BTW, having a parallel feed through the bulkhead halves the current through the small bulkhead connectors which is the weak point.
     
  5. coalman

    coalman Well-Known Member

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    I also did the headlight relay upgrade. Thanks
     
  6. MileHighDart

    MileHighDart FABO Gold Member FABO Gold Member

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    If I remember correctly, the madd electrical bypass shows doing away with the bulkhead connectors for the two wires we’re talking about. And drilling out the plastic and running continues wire through and back out, thus eliminating the connectors altogether. At least that’s how I did mine
     
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    • coalman

      coalman Well-Known Member

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      I agree, did you splice the black and red at the fusible link? Thanks for your reply
       
    • threewood

      threewood Well-Known Member

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      I did on mine, exactly as it's shown on the schematic
      AMP-GA27.jpg

      20170629_173908.jpg
       
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      • coalman

        coalman Well-Known Member

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        Man you are up early, what model car did you do this to? Thanks
         
      • rklein383

        rklein383 Well-Known Member

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        I choose to keep the bulkhead connectors based on the current draw through the connectors was minimized even more by using headlamp relays.
         
      • Mattax

        Mattax Just the facts, ma'am FABO Gold Member

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        The advantage of this is potentially better connections for the power when starting or running on the battery. amp-ga27-jpg.jpg

        But the disadvantage of this arrangement is power flows a longer distance and through two fusible links, which are by definition smaller wires.
        MADB-running.jpg

        Better to run the vehicle from a direct feed from the alternator as illustrated below.
        MADB-revised-direct.jpg
        Fusible links still protect equipment downstream from the battery.
        When the engine is running, the alternator will recharge the battery through the wire marked Charging.
        Everything else that's attached to the main junction gets power direct with just one splice.

        During start, power will flow from the battery to the main junction through the path of least resistance - or some proportion of each if the resistances are similar.
         
        Last edited: Aug 29, 2018
      • MileHighDart

        MileHighDart FABO Gold Member FABO Gold Member

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        Yes I did
         
      • Mattax

        Mattax Just the facts, ma'am FABO Gold Member

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        A variation on this is to run parallel wires through the bulkhead and instead of splicing, use ring terminals on the end and the ammeter stud(s) for the junction.
        If not keeping the ammeter then this would require an stud insulated from the chassis.
        If keeping the ammeter, it allows the option of bypassing it (everything attached to one stud) or keeping it in the charge circuit (wire from alternator to one stud, wire from battery to the other).
        Some on the mopar forums call the parallel wires to the ammeter the "NachoRT" bulkhead bypass since he first posted this.

        parallel-redrawn.JPG
         
      • threewood

        threewood Well-Known Member

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        West coast time, I just got home from work. This was a 69 GTX with factory alternator. I also added relays for the lights and fuel pump.
         
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        • coalman

          coalman Well-Known Member

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          Thanks... I also have the head light and electric fuel pump relays....
           
        • crackedback

          crackedback FABO Gold Member FABO Gold Member

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          I'm not a fan of the MAD method. I prefer to run a protected wire from the alt to starter relay, leave all OEM wires in place and bypass the ammeter. If the bulkhead is in good shape, go with it.

          Plenty of ways to improve on the crummy charging route of our old mopars.

          Pick your parts, pay your money.
           
        • coalman

          coalman Well-Known Member

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          Are you saying to run an extra wire from the alternator to the starter relay? My factory 12 gauge black wire runs from the alternator, to the bulkhead connector, and I have already bypassed the ammeter. Thanks for advice
           
        • coalman

          coalman Well-Known Member

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          I opened up the bulkhead connector today, a lot of corrosion in the 12 gauge alternator wire. the male pin was easy to clean up, not so much luck on the female side. I am going to clean it up the best I can see what happens. Thanks for everyone's input
           
        • crackedback

          crackedback FABO Gold Member FABO Gold Member

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          Yes run an 8 gauge wire from charge stud to starter relay with a fusible link or fuse holder in it.

          I build them.
           
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          • coalman

            coalman Well-Known Member

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            Thanks for the input....
             
          • coalman

            coalman Well-Known Member

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            The original wires Red and Black are both 12 gauge to the Amp gauge. I am looking at both ways of doing it. The first way is I am just going up to a 10 gauge wire from the Alternator to the starter relay as MAD shows. The other would be a 10 gauge with an inline fuse as you show. What do you think, and what AMP fuse? Thanks a lot...
             
          • Mike69cuda

            Mike69cuda FABO Gold Member FABO Gold Member

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            upload_2018-9-2_8-36-13.jpeg

            Here is one of the easiest to read current vs wire size charts that I have seen. Keep in mind that the circuit length includes the return (ground) side if it has a length of wire before it is tied to chassis ground.
             
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            • Mike69cuda

              Mike69cuda FABO Gold Member FABO Gold Member

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              As a general rule, wiring should be sized for twice the maximum current flow and fused at 1.5 times the max current flow. The length of the wire affects the wire size as shown in the chart also. Running over 80% of the rated fuse capacity will result in unpredictable fuse performance. It may work or you may blow fuses randomly.
               
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              • Mike69cuda

                Mike69cuda FABO Gold Member FABO Gold Member

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                Also, keep in mind that if you are running fusible links in parallel, you are doubling the maximum current you are allowing in the circuit. Fuses in parallel add. I’m not saying this is bad, maybe it is what you want. You should just be aware that you are doing it and make sure that the whole circuit can handle it.
                 
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                • coalman

                  coalman Well-Known Member

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                  If I run it as MAD shows the Red and Black from Ammeter are on one fusible link and the Black from alternator is on the other one. So is adding the other wire with a fuse not good? Thanks for your input...