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Technical Is it ok to use 12volt battery in 6 volt system?

Discussion in 'The Hokey Ass Message Board' started by Wizard, May 25, 2020.

  1. Wizard
    Joined: Jun 27, 2006
    Posts: 576


    Have A 55 T bird with 6 volt system. Always used a 6 volt battery but don’t drive it much and battery goes dead. Used the battery charger and kept a automatic battery charger on it but lately battery is dead and can’t revive battery. 6 volt batteries hard to find and Don’t know the price of them now. What happens if you put a 12 V battery in a 6 V system. Will it damage the system after using it for a while. I don’t want to convert it to a 12 V system.
  2. squirrel
    Joined: Sep 23, 2004
    Posts: 53,387


    If you put a 12v battery in a 6v system, and you don't change the light bulbs, they will all burn out. And the battery will not get charged by the generator, because it only puts out 6 volts. And the radio will not work right, and the gauges might get damaged.

    Tractor supply places sell 6v batteries. Last one I got was around $100, which is not bad compared to most 12v batteries. But that's a group 1, and the Bird might take a different size? I don't remember...
  3. KoolKat-57
    Joined: Feb 22, 2010
    Posts: 3,060

    from Dublin, OH

    It will damage most of your electrical components, although the starter motor will turn over faster!
  4. Interstate has a 6V as does Optima…I’ve used both....
    Boneyard51 likes this.

  5. I was stubborn with sticking to 6v on my 55 for a few years. Dont bother with it and swap the car to 12v. Even though tractor supply and other places do have 6v batteries in my experience its hard to find them that havent sat on the shelf for years. And if you die on the side of the road cant even get a jump from a passer by. In total its cost about 300 dollars to swap my car over including the battery
  6. Boneyard51
    Joined: Dec 10, 2017
    Posts: 6,263


    How did you deal with your 6 volt gauges with the 12 volt battery?

    VANDENPLAS likes this.
  7. egads
    Joined: Aug 23, 2011
    Posts: 1,378


  8. railcarmover
    Joined: Apr 30, 2017
    Posts: 716


    Generator doesnt care what voltage it sees,the rest of the system does..its not hard to convert to 12v,they are the cheapest bulbs out there...but instead buy a 6v battery,doesnt seem you run the car much
    VANDENPLAS likes this.
  9. cs39ford
    Joined: May 1, 2012
    Posts: 925


    Just go to interstate get there 6 volt. They last about 5 plus years. Those tractor batteries last about A year if you are lucky. My experience
  10. squirrel
    Joined: Sep 23, 2004
    Posts: 53,387


    pretty easy, just install the instrument voltage regulator for a 56 Tbird.
  11. They use to make a battery that had a switch mounted on the top in the middle.It allowed the starter to crank on 12 V,and once started it switched to 6V.Saw one in a buddies 41 Ford PU.May take some hunting,but I bet a good battery shop could still get one.
    Boden likes this.
  12. deucemac
    Joined: Aug 31, 2008
    Posts: 1,377


    1956 was the only year Ford used 12V gauges and had nothing but trouble. They went back to the old trusty King Seeley gauges for 1957 and used an instrument voltage regulator to power the gauges at 6v. NAPA still sell them listing it for a 1959 Ford. Later years the IVR was used in printed circuit board and used snaps. The 1959 uses spade connectors and wires in easily. Ford used that set up through 1985 and then got the bless than brilliant idea to follow GM and use magnetic gauges. And that gave us Ford mechanics our second gauge nightmare .
  13. Vimtage Iron
    Joined: Feb 28, 2010
    Posts: 560

    Vimtage Iron

    Those 6/12 batterys cost a small fortune.
    I bought an optima for a stock Model A 200 $ but it has a 3 year full replacement warrenty, the wet cell 6 volt batterys do not, 6 months full replacement and then pro rated after that and the group 2 is about 125 to 140 $ and they don't last for shit.

  14. I actually wired those up this evening. Used a ford factory instrument panel voltage reducer. All ford gauges are 6v up into the late 70s early 80s. They installed this reducer on them to drop voltage to 6v. Im using one off a bronco it was fairly simple to wire in and i believe i paid around 30 dollars for it from mac's.
    alanp561, Boden and Algoma56 like this.
  15. People do not seem to understand the question being asked.
    Read the orig post carefully.
    When you read the original post again, it really asks about how a 12v battery reacts when it is charged to 6V by the car charging system, and used as a 6v battery.
    He didn't ask about pumping 12v into the car.
    He didnt ask about converting the car to 12v.
    The question simply was about taking a 12v battery, and using it and charging it as if it was a 6v.
    Does using and charging a 12v battery at 6volt levels harm the 12v battery, and its life and function?
    He doesnt have confidence in batteries made as 6v batteries, so is using a 12v battery at 6v levels a useful thing, or will the 12v battery not like being used at 6v charging voltage and used as a 6v ?
    I am curious about that answer too.
    Does taking a 12v battery, and using it at 6v charging level as if it were a 6v battery harmful to the battery life?

    Last edited: May 25, 2020
  16. patsurf
    Joined: Jan 18, 2018
    Posts: 774


    i don't think you really understand a charging system...not picking on you,just saying...
    XXL__, alanp561, 5window and 2 others like this.
  17. The37Kid
    Joined: Apr 30, 2004
    Posts: 29,867


    The stock 6volt wiring harness is a larger gauge than what would be in a 12 volt "kit" correct? What happens when a 12volt system uses the thicker wire?

    mitch 36 and Boneyard51 like this.
  18. redo32
    Joined: Jul 16, 2008
    Posts: 2,042


    Nor does he understand any other aspect of automotive electrical system.
    A_Burly_Wind likes this.
  19. 12v car with a 6v battery = no starty starty

    6v car with a 12v battery = fried electrical components. Simple enough?

    6v wiring is larger because a 6v system pushes more amperage. The 12v battery and other components dont act any differently than they would with the larger sized wiring.
    XXL__, alanp561, pitman and 4 others like this.
  20. Also a 12v battery pushes 12v. Just because the generator or regulator or rest of the car is 6v parts the battery still sends a full 12v to everything before ot drains due to the charging system not able to keep up. And the 12v can cook the gauges and the bulbs.
    loudbang, egads and Boneyard51 like this.
  21. squirrel
    Joined: Sep 23, 2004
    Posts: 53,387


    The voltage of a battery, depends on it's chemistry. A 12v battery is a 12 volt battery, you can't use it at 6v. It doesn't work that way. Each of the 3 cells in a 6v battery produces a bit over 2 volts, just like each of the 6 cells in a 12v battery produces a bit over 2 volts. Because that's what a lead-acid battery cell does.
    loudbang, jaracer and VANDENPLAS like this.
  22. Boneyard51
    Joined: Dec 10, 2017
    Posts: 6,263



    loudbang, VANDENPLAS and egads like this.
  23. BuckeyeBuicks
    Joined: Jan 4, 2010
    Posts: 2,619

    from ohio

    I will second that. My friend has a nice 55 Bird that may get driven about 500 miles a year. He is always bitchin that he has to buy a new 6 volt battery about every year from Tractor Supply. I have given up telling him to buy a Interstate or other good brand battery so I just grin when he starts ranting about the cheap assed junk 6 volts he still keeps right on buying.
    cs39ford, egads and Boneyard51 like this.
  24. MAD MIKE
    Joined: Aug 1, 2009
    Posts: 724

    from 94577

    Didn't any of you guys ever play with batteries and a volt meter as a kid?
    You do not want to put a 12volt battery in place of the 6Volt battery.
    Everything will work really well for a moment and then burn out.

    If a good 6V was hooked up in series reverse polarity with a 12Volt battery then the total voltage would be 6volts. With a dead 6V battery, who knows what you may get in voltage, if anything reliable.
    However, I don't know if one of the batteries would become the load and overheat, off gas, and possibly explode.

    I do not know if there is a large enough resistor, or bank of, that you could reliably use so as to maintain your 6V system, yet use a conventional(readily available) 12V battery.
    Last edited: May 26, 2020
  25. 27 Tall T
    Joined: Dec 16, 2005
    Posts: 327

    27 Tall T
    from Butler Pa.

    If your t bird is 3 speed overdrive, 12 volts will also burn out your transmission solenoid.
    alanp561 and rbrewer like this.
  27. Wizard
    Joined: Jun 27, 2006
    Posts: 576


    Yes, it is a 3 speed overdrive transmission. Thanks to all who responded here with your answers for my question. Kinda figured I better just stay with a 6 volt battery before I asked and the general opinion and answers is to stay with 6 volt battery. So, I will look up prices of interstate battery and Autobone and advance auto to see their prices and few other places for a Group 2N battery. Will also measure the battery base in car and the battery before purchase just to make sure it will fit in car correctly.

    Thanks to all
    rbrewer likes this.
  28. southcross2631
    Joined: Jan 20, 2013
    Posts: 4,414


    I had a 53 Ford that was my daily driver. The battery didn't go dead ,but when it got hot outside the car would not start consistently unless you jumped it with a 12 volt battery. I converted it to a 6 volt alternator and no more no start issues, much better lights. No hassle about changing over all of the bulbs no voltage reducers. Straight bolt on same belt . Best thing I could have done for that car. Drove it for 3 years after the conversion.
    The company was out of Kansas that made the alternator. They do a lot of one lap of America stuff.
    loudbang and squirrel like this.
  29. pitman
    Joined: May 14, 2006
    Posts: 5,149


    Volts = EMF, Electro-motive-force.
    12v is only to happy to go thru oversize 6v cable/wire.
    Prob. occurs when twice-force reaches sensitive hardware!
    Peg a meter/guage and watch varnish vanish.
    egads likes this.
  30. brading
    Joined: Sep 9, 2019
    Posts: 641


    Can you get this type of battery in the States. its a 12v battery with a 6v take off. You use a 12v generator / alternator to charge it. Wire it up right so that you use 12v for starting and connect up you 6v side to the 6v terminal 9 the one with the red lead. I have seen many moons ago guys putting a screw through the top a battery to pick up on the third cell for 6v

    Attached Files:

    egads, VANDENPLAS and Boneyard51 like this.

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