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Connecting Two Batteries together

Discussion in 'The Hokey Ass Message Board' started by grits, Mar 1, 2011.

  1. grits
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    grits Member

    This is a question for you electical gurus, I dont have a lot of room in the trunk of my coupe for the battery and a friend suggested I use two 6 volt batteries, one on either side of the trunk and tie them together to make a 12 volt system, seems like it would still be 6 volts, am I an idiot or what?

    So help me I'm just not sure.:eek:
  2. 2 - 6 volt batteries is still 6 volt. HRP
  3. maniac
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    maniac
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    If you wire them in series, all you will have is 6 volts.

    If you can't fit a 12 volt battery how you gonna fit 2 6's, last time I looked they were around the same size.
  4. seventhirteen
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    seventhirteen Member

    still 6 volts and why would you do that anyways?
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  5. flacoman
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    flacoman Member

    Wire them in series ' + term to - of the other . The two remaining terminals will be 12V
  6. pitman
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    pitman
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    In series, the voltage is cumulative. In parallel its current is cumulative.
    Add 'em up!
    Measure w/your VOM/multimeter and it will be obvious. If you wanted to have 24 volts, buy two more batts.
  7. grits
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    grits Member

    Thanks HRP, I have thought this over several times and have argued that point with him.
    Last edited: Mar 1, 2011
  8. Dreddybear
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    Dreddybear Member

    I disagree..

    Wire in series will produce 12 volts.

    Wired Parallel will produce 6 volts with more capacity.

    Ground to - battery A.

    + Battery A to - Battery B

    + Battery B 12 Volts
  9. seventhirteen
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    seventhirteen Member

    i stand corrected, learn something new everyday, read this, your friend is correct

    course i still wonder why you would want to do this...
  10. porknbeaner
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    porknbeaner Member

    They make very small batteries for the street rod crowd. Get one of those. More often than not a 6V is the same size or bigger than a 12V battery anyway.
  11. pitman
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    Hold your cards...we may have a winner!:p
  12. Timbo from Mempho
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    Timbo from Mempho Member

    Optima 6 V batteries are really small, bout like 3 tall boys standing side by side. When hooked in series (Positive from batt 1 to Negative on batt 2) you will get 12 volts. When hooked parrallel (Pos to Pos and Neg to Neg) you would only get 6 volts.
  13. Mr48chev
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    Correct he is. A lot of Cat loaders use six volt batteries wired in series to get higher voltage. Among other rigs. Wired parallel would just create a bigger 6 volt though.
  14. justford
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    justford Member

  15. grits
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    grits Member

    That is what he is telling me.

    I dont want or need 24 volts, the question is can I use two smaller 6 volt batteries wired in a fashion to get the 12 volts needed.

    I thought of one smaller on each side of the trunk kinda tucked behind the quarter panels,
    that would give me a little more room.
    Last edited: Mar 1, 2011
  16. Dreddybear
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    Dreddybear Member

    I meant I disagree with the other couple guys :p
  17. 35desoto
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    35desoto Member

    If you join the positive terminal of one battery to the negative terminal of the second battery the two remaining terminals will give you a 12 volt system. Thats not a silly idea if room is your problem.
  18. maniac
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    Mostly to get higher amperage, My KW has 4-12 volt batts, 12 volt starter, originally came with 3, I aded one for the amps here for the cold weather.
  19. belyea_david
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    belyea_david Member

    It should work just fine - Remember for 12V from 2 x 6V to connect the '+' terminal from battery 1 to the '-' terminal from battery 2 with the largest gauge wire you can locate. I would suggest 0 (zero) or 0/0 gauge wire with soldered terminals.

    The '-' terminal from Battery 1 will be '-' ground and the '+' terminal from battery two will be your normal '+' battery terminal.

    It will be tough to jump start if needed, but it should work fine.
    Last edited: Mar 1, 2011
  20. westex_rat
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    westex_rat Member

    I say do it, and take a picture. sounds very practical
  21. grits
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    grits Member


    BINGO!

    Thanks for all the quick replies, you guys are great.
  22. theHIGHLANDER
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    theHIGHLANDER Member

    It all sounds like re-inventing the wheel to me. Extra wire, extra battery, 2 mounts, double the related electrical hardware, vs finding a heavy duty small battery. I won't bother to repeat how to get 12 from 6...
  23. seventhirteen
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    seventhirteen Member

    makes sense now, like i said learn something new everyday
  24. Marshall Metal Shaping
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    Marshall Metal Shaping Member

    Have a look at Odessey batteries....they are a dry cell. I put one in my smallblock powered A with a high torque starter. A p680 I believe, works great!
  25. 1950ChevySuburban
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    1950ChevySuburban Member Emeritus

    Let me throw this out there.......

    When I worked in the RV industry, most RVs had room for two 6-volt batteries next to each other for the coach side (Not the engine starter). It's a known fact that two 6-volt batteries at 800cca each in series will outperform two 12-volt batteries at 800cca each in parallel.
  26. 1950coronet600hp
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    1950coronet600hp Member

    yeah 2 6v in series will give you 12v with no bump in amp supply.. now.. unless you run an optima most of those series 1 batts will only supply 450cca.. that isnt much.. what are ya cranking over? also you might want to think about an optima or some other sealed battery, the reason for this is you can mount em in any posistion you like.. might be able to mount it sideways somewhere and make a 12v battery fit.. all this reminds me of my friends time on the R+D team at vector, there wasn't enough room for an adequate size battery at the time to crank that high compression v8. so Jerry's thought was to get one of those batteries at the time that had a lever on top you could flip for a little extra amps, and one of my friends jobs was to make a cable pull system so you could do this from the dash. ahh vectors.. but thats a story for a different board...
  27. Dale Fairfax
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    Dale Fairfax Member

    Have you priced a 6 volt battery lately? It's a damned expensive way to get 12 volts. And I'm sure you can find a 12 v. battery that's near the same size as a 6 v.
  28. Da Tinman
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    Da Tinman Member

    I helped a guy do a 12 volt conversion, he used a 6 volt under the hood so it looked stock and another 6 volt in the trunk, wired in series to get the 12 volts.

    if you really want to confuse yourself you can wire them in series/parrallel and get 12 volts and twice the amperage.
  29. Vimtage Iron
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    Vimtage Iron Member

    Yes you can wire two 6 volt batterys and make 12 volts, but you need to run large cable from one battery to the other and up to the starter, and that starts to get pricey, minuim 2 ought cable for batt to batt and should do the same up to the starter.
    Group 31 12 volt batterys get you about 850 to 900 cranking amps they cost about $113.00 the large 6 volts run 900 to 1000 amps but they run about 100.00 also.
  30. davidbistolas
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    davidbistolas Member

    Agree - 2 x 6 = 12. But 2 6 Volt batteries is NOT equal to one 12 volt battery. The cranking amps is not the same.

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