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Help with does and don'ts 6V to 12V convwersion

Discussion in 'The Hokey Ass Message Board' started by TudorTony, Feb 18, 2014.

  1. TudorTony
    Joined: Jun 2, 2013
    Posts: 218

    TudorTony
    Member
    from NJ

    Messed up the title and prefix let's trey again.
    I'm switching to 12 V on '35 Ford, installing one wire alternator as well. Already have changed all the bulbs. Gauges don't appear to need anything as Gas gauge is pressure type no electric and it shouldn't matter on the amp meter. Been told starter will be fine and turn faster ( a good thing ).
    - With the stock '35 ( new wiring ) in place can I use the existing generator wire in harness to connect the one wire alternator? Looks like yes looking at the wiring diagram?
    - Do I need to convert from Pos. grnd to neg. grnd as part of the 6V to 12V / alternator conversion? If I do dose anything else need to be changed.
    - Will the coil connection be effected?
     
  2. anthony myrick
    Joined: Sep 4, 2009
    Posts: 6,997

    anthony myrick
    Member

  3. TudorTony
    Joined: Jun 2, 2013
    Posts: 218

    TudorTony
    Member
    from NJ

    Thx Anthony, looked for something like this on the Internet and couldn't find in all in one place.
     
  4. 5th Avenue Garage has a little book which clearly explains how to do this, along with the right diameter and width pulleys to drive things correctly with the existing crank pulleys. Good folks to work with.
     

  5. I, personally do not like one-wire alternators, but, you only need hook up the one wire to the battery. It won't charge at idle (the advantage of an alternator over a generator, lost with this one), but is simpler to wire by a small bit.
    Yes, must be negative ground. Electric motors (except the starter) will turn backwards, but you probably don't have any.
    Coil should be swapped for a 12V internally resisted coil, or a resistor put in line with the power lead. Coil leads should be swapped as well.

    Cosmo
     
  6. TudorTony
    Joined: Jun 2, 2013
    Posts: 218

    TudorTony
    Member
    from NJ

    So in summary as I am pretty thick headed, If I stay with the Positive grounding as the original car is and go with 12 volt battery these are the things to be done:
    -change all bulbs to 12v
    - on one wire alternator run one 10 gauge wire from the alternator to positive battery terminal. ( don't use old generator wire in stock '35 Ford harness? )
    - If engine is set up for Negative ground system then switch the leads on the coil i.e. coil wire in stock harness goes to the negative side of the coil and positive side of coil goes to distributor.
    - the only electric motor is in the heater and if I stay positive ground as the car was originally positive ground the connection can stay as is. ( but will need ballast resistor to reduce from 12v to 6v as not to burn up motor)
    Is that about it right??
     
  7. Also wise to bypass your factory amp gauge . Just put both wires to the gauge on one terminal . Why? You amp gauge likes a max of 30-40 amps....the one wire alt is capable of at least twice that .




    .
     
  8. Ebbsspeed
    Joined: Nov 11, 2005
    Posts: 5,419

    Ebbsspeed
    ALLIANCE MEMBER

    Once the alternator energizes it will charge at idle.

    Only permanent magnet motors will run backwards. Series wound will not, and most of the electric motors in older cars are series wound.

    Tony, if you stay with positive ground, you will need to use an alternator designed for a positive ground vehicle. They are around, primarily european, not sure if there are any typical delcotron type around that are positive ground. Or you could build an elaborate mounting system that would insulate the frame of a negative ground alternator from the rest of the car, attach the frame of the alternator to the battery, and the "one wire" from the alternator to the car's frame and engine block.
     

  9. Is your heater motor single speed? and how many wires ?
     
  10. diamond dave
    Joined: Jul 18, 2006
    Posts: 459

    diamond dave
    Member

    ive got the little red book mentioned above for the conversions. it's great. ive done a couple 6-12 conversions over the years. i'm pretty sure that you have to run the wires to the ammeter the opposite way that they were hooked up, when changing from neg. ground to pos. ground.
     
  11. Yup. That's a lot simpler than moving two battery terminals...:rolleyes:

    Another thing to think about: if you break down on the road, will you be able to source repair parts on a Sunday afternoon?? Getting those special parts might wrk initially, but when you're out of town and need to get back home, those special parts can be a real pain.

    Cosmo
     
  12. TudorTony
    Joined: Jun 2, 2013
    Posts: 218

    TudorTony
    Member
    from NJ

    Guess that's why there's not much out there on 12v positive ground system. Seemed to make sense to keep the polarity on the car the same as it was and just change the coil connection. Obviously a bad idea if I want to go with the Alternator instead of a 12v generator.
    I will go negative ground and stay with the alternator.
    Thx for the good advise. Done deal.
     

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