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how to convert 12v to 6v

Discussion in 'The Hokey Ass Message Board' started by wingman9, Nov 12, 2012.

  1. wingman9
    Joined: Dec 30, 2009
    Posts: 804

    wingman9
    Member
    from left coast

    I have a Unity driving light that has a 6 volt GE sealed beam bulb. I've searched for a 12 volt replacement but I can only find fog or spotlight bulbs. Next step would be to step down 12v to 6v to make what I have work. Any recommendations?
     

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  2. Fenders
    Joined: Sep 8, 2007
    Posts: 3,921

    Fenders
    Member

    What is the bulb number?
     
  3. Rich Wright
    Joined: Jan 9, 2008
    Posts: 3,922

    Rich Wright

    You should be able to buy a voltage drop. they used to be common fro protecting 6V gauges, etc, when converting 6V to 12V but I haven't seen one in quite a while.
     
  4. wingman9
    Joined: Dec 30, 2009
    Posts: 804

    wingman9
    Member
    from left coast

    I can't read it. It's partially wiped out. Whats readable is GE Mazda and the number ends in 03. 5 3/4" bulb
     

  5. check napa auto parts. they can get them
     
  6. BobF
    Joined: Dec 30, 2004
    Posts: 232

    BobF
    Member
    from Poway, CA

    I'm not sure if the resistance of the filament changes with the heat it generates but most likely it does. Measure the resistance of the bulb and if I correctly remember my basic electronics get a resistor of the same approximate value (ohms) and place it in series with the bulb. Should drop approx 6 v across each, which you can check with a VOM. If the resistor is slightly higher R than the bulb it will be less bright but last longer, more drop across the R than the bulb.
     
  7. 19Fordy
    Joined: May 17, 2003
    Posts: 8,025

    19Fordy
    Member

    I used this resistor to drop 12V to 6 V for my BATT Gauge on a 40 Ford. Just install it in series in your 12 V wire. You can buy them on line. Very cheap.
     

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  8. GeezersP15
    Joined: Dec 4, 2011
    Posts: 555

    GeezersP15
    Member
    from N.E. PA

    As suggested, try NAPA for a 12V replacement bulb. But, if you can't get one, a resistor will certainly work. You'd need a resistor with the same resistance as the bulb (or as close as you can get it), and the resistor has to have an adequate wattage rating to carry the current. As an example, if the 6V bulb draws 5 amperes of current, then 5 amperes multiplied by 6 volts equals 30 watts of power. The resistor you would use would also be dissipating 30 watts of power (heat) to provide the voltage drop. A resistor with too low a wattage rating would just overheat and fail in a short time. A resistor with a higher wattage rating than you need is perfectly OK. Also consider that the resistor will get very hot when the light is turned on, so locate it where the heat won't be a problem.
     
  9. jcmarz
    Joined: Jan 10, 2010
    Posts: 4,631

    jcmarz
    Member
    from Chino, Ca

    What size is the light itself? Because Unity sells replacement lights for driving as well as fog in 5 and 6 inches. 6 or 12 volt. Other place that carries them is Kanters.
     
  10. fixn4ds4u
    Joined: Feb 5, 2014
    Posts: 2

    fixn4ds4u
    Member
    from Canada

    Hello everyone. I have a 1952 Mercury M-3. I plan to solve this conversion problem in a unique way. I am going to put an alternator in addition to the generator. It will charge a 12V battery that will run ALL lights, accessories, new stereos, heater motor etc. The 6V system will work as normal, powering starter, coil, ignition, original radio etc. Has anyone on here ever done this before? Any problems I haven't thought of?

    fixn4ds4u
    1952 Merc
     
  11. Hackerbilt
    Joined: Aug 13, 2001
    Posts: 6,254

    Hackerbilt
    Member

    I've NEVER converted a 6v to a 12v...but that seems like the most complicated and expensive way someone could come up with to do the job.

    My expectation is that the starter won't care if its 12v or 6v hitting it and the ignition would only require a coil change to work correctly?

    As I said...never did it before...but I would be "shocked" :D if it turned out to be a complicated as you seem to think it is!
     
  12. It technically will work, but thats the hardest way of doing it Ive ever heard of.
     
  13. To the OP, and Yes I realize this is over a year old, you can get the right bulbs direct from Unity. http://www.unityusa.com/
     
  14. The 6v starter will turn a lot faster on 12v, just ask all the early VW guys.
     
  15. Why? Why would you do this? The starter will run fine on 12v as long as you don't cranks for a long tie. coils are cheap - the rest of the ignition is not voltage sensitive and the original radio can be run off a voltage drop or shunt.
    That is just crazy talk:eek:
     
  16. flamin01a
    Joined: Jul 23, 2005
    Posts: 78

    flamin01a
    Member

    My friend Put Smith says to use aluminum cable to the starter.
     
  17. 19Fordy
    Joined: May 17, 2003
    Posts: 8,025

    19Fordy
    Member

    I strongly suggest that you NOT follow your friend's advice.
     
  18. Why is that? Delphi has been making Aluminum Battery cables for the OE's for sometime now - both passenger cars and Big Commercial Trucks.

    Read this if you want to know a little more http://delphi.com/shared/pdf/ppd/ee/aluminum-cable-systems.pdf
     
  19. 19Fordy
    Joined: May 17, 2003
    Posts: 8,025

    19Fordy
    Member

    Thanks for the info. I always thought copper was the best conductor of electricity. Plus, I was thinking about how the aluminum wiring used in some homes during the 70's and 80's caused electrical (fire) problems due to corrosion. I thought the same problems might happen if aluminum wire was used in cars.
     
  20. hardluckharv
    Joined: Oct 31, 2012
    Posts: 31

    hardluckharv
    Member
    from edmond,ok

    As far as the op goes try a motorcycle shop preferably some who deals with vintage triumph, b.s.a., Norton.
    As far as the 12 volt conversion with a alt and a generator that is crazy talk. If you want to......you can run two 6 volt batteries in a series, run every thing off the first Batt that is 6 volt and components that are 12 off the second. Run a 12 volt alt or gen. But it is a silly way to do it today. Just run it 12 volt you can buy runtz reducer..... ...if you must. But remember ford used 6 volt gauges up into the 70s......so just get a voltage reducer for a 69 ford pick up at your parts store or local salvage.

    They stopped using aluminum wiring when house started burning down from faulty aluminum wiring.

    Posted using the Full Custom H.A.M.B. App!
     
  21. G-son
    Joined: Dec 19, 2012
    Posts: 1,276

    G-son
    Member
    from Sweden

    Silver is the best conductor, copper second and aluminum third - relative to metal thickness. If you go by weight, there's a chance a thick aluminum wire might beat the same weight of silver or copper due to those being so much heavier.
     
  22. The problems associated with Aluminum Wiring in houses were due to incompatibility of the wiring to connectors along with non insulation that allowed corrosion. That corrosion in Aluminum oxide, which becomes an insulator instead of a conductor.
    The standards were changed and Aluminum wire is still used today. It is also used in Aircraft and has been a preferred wire since the early 1900's in the Power Grid.

    Aluminum actually has a HIGHER conductivity to weight ratio than copper.
     
  23. fixn4ds4u
    Joined: Feb 5, 2014
    Posts: 2

    fixn4ds4u
    Member
    from Canada

    Thanks for the replies! Some of the comments on here make me want to do this even more, just to prove that it will work out! BTW I have done lots of 6-12V conversions like the ones you guys are talking about for other people. This one is my own truck. I am going to go even one more and put a switch in-line so that I can turn the alternator off when it's not required. I will post the results as they happen.
     
  24. Hackerbilt
    Joined: Aug 13, 2001
    Posts: 6,254

    Hackerbilt
    Member

    Nobody said it couldn't work. Just that its a lot more expensive and complicated than it needs to be.
    But then again this IS a hobby so have fun doing the things YOU want to do! :D
     
  25. Yeah, that'll teach em ;) No one is saying it won't work, they are saying it is silly and complicated when it doesn't need to be. But you go right ahead and do the work and spend to money and teach em! :eek:
     
  26. Ebbsspeed
    Joined: Nov 11, 2005
    Posts: 6,250

    Ebbsspeed
    ALLIANCE MEMBER

    I assume that after 15 months have passed since the OP, the issue has been resolved one way or another. If not, then wire another 6-volt headlight in series.
     
    Last edited: Feb 13, 2014

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