Trunk Mount Batt. Opinions needed

Electrical and Ignition

  1. Kendog 170

    Kendog 170 Let the boy go !

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    Ok so I plan on redoing my trunk mount Battery wiring (68 Dart) due to cranking issues. I’m keeping 1ot Positive wire Batt. To Ford solenoid then solenoid to starter. 10Ga. Jumper on starter. Removing 10 Ga. That I had from Alt. (Denso 1 Wire) to Starter relay with fusible link. Changing to diagram with CD relay. What Ga. Should I use for that (Alt. to trunk) 4Ga.?

    Also, what Ga. Should I be using on the Master Disconnect wiring?

    My ground is 1ot. Currently goes to stud welded to rear frame rail. Another 1ot. From stud on front rail to engine block. I plan on keeping front rail to engine ground, but also running Battery ground wire to the starter mounting bolt. Back of motor to firewall is also grounded.

    Debated eliminating to Disconnect entirely mostly street driven but still a good safety item. (Bumper mounted)

    Thanks

    Trunk mount Batt. Wire Diagram.jpg
     
  2. Steven190

    Steven190 FABO Gold Member FABO Gold Member

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    I just put a disconnect in the negative ground wire, ran the cable to the starter stud. I put the disconnect in a spot that was covered by the frame, and acts in a safety hidden position.

    Battery Switch.jpg
     
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    • 66jim

      66jim Well-Known Member

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      Did it ever crank over Ok? If so could be weak battery. Not sure what 1ot. is I assume its 1 gauge. I think you may need to go with a larger size (USE WELDING CABLE) for starter and chassis not the regular automotive cable, double check connections use dielectric grease. Unsure it the frame rails would be as good a connection point as the body itself. Maybe a jumper from the body to chassis. I would not use the disconnect another resistance point not needed, make sure wiring to run is fused at the battery.
       
    • Dfr360cuda

      Dfr360cuda MAGA Again

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      I'm assuming the CD relay is a normally closed relay setup like Oldmanmopar has to shut off his alternator during racing.
       
    • roccodart440

      roccodart440 Well-Known Member

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      I put my remote shutoff through the center of the license plate

      Biggest thing with trunk mount setups is actually the grounds. I added an extra ground and it made as world of difference.
       
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      • Oldmanmopar

        Oldmanmopar Going left turning right FABO Gold Member

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        The only reason I shut the alternator off when racing is to prevent the belt from coming off from resistance when charging. When shutoff there is no drag on the belt. shift light set at 8000 and My engine has seen RPM's up to 9300. The belt and alternator couldn't take those RPM's while charging. All I did to move my battry to the rear was to run a cable to a bulk head in the front that acted as my battery under the hood. All the original wiring and the starter relay was kept under the hood. The bulk head was my positive cable. I used a solenoid to kill the alternator.

        Steve 101.JPG

        Steve 102.JPG

        Steve 105.JPG
         
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        • Kendog 170

          Kendog 170 Let the boy go !

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          It would crank over just ok. When warm it would sometimes need a jump. This was with a new battery. Current battery dips to 11 Volts when cranking. I have a new starter in it as well. Thinking Alt. wires should go direct to Batt. for better charging ? Alt. puts out 14.25 volts.
           
        • kursplat

          kursplat FABO Gold Member FABO Gold Member

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          1/0, it's the next size up from #1.
           
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          • 66jim

            66jim Well-Known Member

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            Heat shield or wrap for starter
             
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            • roccodart440

              roccodart440 Well-Known Member

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              I talked to powermaster and they said do not

              I tried it both way and no wrap was better.
               
            • 66jim

              66jim Well-Known Member

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              Don't see how it could hurt, headers may be close,every application is different. Helped me costs under 20 bucks.
               
            • roccodart440

              roccodart440 Well-Known Member

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              They claimed it actually holds heat in.
               
            • Treblig

              Treblig Well-Known Member

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              I always use 2 AGW (2 gage) welding cable. It's the same cable I have on my 220 stick welder. I used the frame for a ground from the engine bay to the trunk. But before you buy some welding cable, place the battery in front and see if it cranks any better?? If it does crank better then you probably need a heavier positive cable from the trunk to the engine bay. I also soldered (solder slugs/pellets) eyelet ends on the cable to avoid a bad connection and corrosion build up. If your positive cable is too skinny it will cause too much resistance so that you lose voltage, the longer the cable the more you lose!!!.
              https://www.napaonline.com/en/p/NW_728121?intent=true
              https://www.tractorsupply.com/tsc/product/lynx-2-gage-copper-lug

              I was always checking craigslist for people selling welding cable for all my trunk battery installs. You can find some pretty good deals if you keep a sharp eye out, used cable works just fine if it doesn't have any bare spots....and even if it does you could tape it up anyway. Welding cable is also pretty flexible.
               
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              • 67Dart273

                67Dart273 FABO Gold Member FABO Gold Member

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                If you are having cranking issues with 1/0 it is not due to wire size, but rather something else, and there is lots of room

                Wire end terminals.........wire terminals can be corroded or not making as great contact as you think
                Switches. You are going through AT LEAST three switches to the starter........the disconnect, the Ford, and the original Mopar starter solenoid. Any one or two or all three could be introducing drop

                The starter could have a problem

                The ENGINE could have a problem

                Have you done any "actual troubleshooting?" You know what a carbon pile tester is? Have you measured starter voltage and drop along the wiring in the system, and so on?

                "Throwing parts" or "jacking up the radiator cap" is no way to fix anything, unless you simply like to spend money.

                So!!!??? Do some checks. Get/ borrow a carbon pile tester. Get a multimeter and "rig" a long wire---which can be small, even no18---to reach to the far corners of the car, say 15-20ft long, with alligator clips each end.

                Rig a remote starter to the starter relay

                Check ground drop. You really should use TWO people. Clipe one probe of the meter to a good ground on the engine block. Stab the other probe into the top of the battery NEG teminal. Disable ignition so it will not fire. Crank the engine, read meter while cranking

                Post the reading. You are hoping for a very low reading, the lower the better.

                Now clip the meter to the starter side of the Ford solenoid. Stab the other into the top of the POS battery post. Crank and read. Same as above lower the better. You are hoping to see a FEW TENTHS of one volt

                Now move up to the starter main terminal. Clip the meter there, and top on batter POS. Crank and read. Post reading.

                Clip meter to starter main post and engine ground, crank and read. The higher the better Should have bare minimum 10V, acceptable is 10.5 or higher.
                 
                Last edited: Sep 16, 2020
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                • 67Dart273

                  67Dart273 FABO Gold Member FABO Gold Member

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                  How to measure starter draw. You need a carbon pile tester. Clip tester firmly to battery clamps. Crank engine, read meter carefully while cranking. Now, adjust carbon pile load knob to drag battery volts down to THAT SAME READING. Now read ammeter. That reading is your starter draw.
                   
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                  • furyus2

                    furyus2 Well-Known Member

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                    So, what is a CD relay, and how is it different from a standard relay?
                     
                  • roccodart440

                    roccodart440 Well-Known Member

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                    Check your grouds, add another ground

                    I use welding cable as well
                     
                  • Kendog 170

                    Kendog 170 Let the boy go !

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                    Continuis Duty. 67Dart273 told me a week ago.
                     
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                    • Kendog 170

                      Kendog 170 Let the boy go !

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                      I will try to get my brothers friend to help me. He really knows his stuff. Me ? Not so much when it comes to electrical testing.My suspitions are ground related .
                       
                    • kursplat

                      kursplat FABO Gold Member FABO Gold Member

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                      heat shield = good - leaves room for air flow over and around the starter
                      heat wrap = bad - traps heat in big chunk of metal and doesn't let it cool down
                       
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                      • kursplat

                        kursplat FABO Gold Member FABO Gold Member

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                        HEMI style
                        100_2543.JPG
                         
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                        • Treblig

                          Treblig Well-Known Member

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                          nice shield!! If you swapped out for the newer, smaller starter you'd have even more airflow.
                           
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                          • kursplat

                            kursplat FABO Gold Member FABO Gold Member

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                          • kursplat

                            kursplat FABO Gold Member FABO Gold Member

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                          • 67Dart273

                            67Dart273 FABO Gold Member FABO Gold Member

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                            A Ford style starter relay is at least different from continuous duty in that a starter relay has a bigger, higher power (current) winding to pull the contacts in much harder. This results in higher current capacity for the contacts but also means, that a starter relay coil will burn up and cook if left powered too long.

                            It's possible a CD might use the same contacts and construction, but they use a ligher coil with less "pull" which willl not burn up. And, the contacts have less current capacity because of this
                             
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