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can you simply connect two 12v batteries together and be ok ?

Discussion in 'The Garage' started by R72K5, Nov 19, 2003.

  1. R72K5

    R72K5 Banned

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    lets say you had an old daily drier beater chevy pickup and wanted to add a battery to driver side of truck under hood,

    just run hot and neg cables from the existing battery to the additional battery you are adding and be doen with it, it be ok ?


    or would you have to get a larger alternator or different starter or guages or anything ?


    thanks
     
  2. yellowK20

    yellowK20 Well Lubricated Premium Member GMOTM Winner

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    That's what I do with my yellow truck I have dual optimas in it with the stock alternator it does help with cold starting
     
  3. BanksBurban

    BanksBurban Registered Member

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    Yes, run positive to positive and negative to negative and it will be fine. If you use two batteries of the same CCA rating it will help against premature failure.
     
  4. skratch

    skratch 1/2 ton status

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    Yeah I did the same thing on my Suburban. Like he said it really helps with the starting it on cold days.

    Just use large gauge cables, I went a little overboard and ran 00 cables on mine, both batteries and down to the starter and the grounds.
     
  5. rjfguitar

    rjfguitar 3/4 ton status GMOTM Winner

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    That will work fine, almost all commercial applications are wired like this. All my Trucks(Semi's) have 4 huge batteries just wired together like this.
     
  6. HarryH3

    HarryH3 1 ton status Author

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    If you want to get really spiffy, I've got a 70 amp battery isolator that I'd send ya for $20. /forums/images/graemlins/cool.gif That will let you charge both batteries without them draining power from each other. /forums/images/graemlins/thumb.gif
     
  7. mastercraftkpk

    mastercraftkpk 1/2 ton status

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    I recommend getting an isolator so that you don't end up w. 2 dead batteries instead of just 1. They aren't that expensive (<$35.00), and are more than worth it. If you can't do the isolator now, yuo can always add it later.

    Be sure to go + to - and - to + or you will get a suprise w/ 24 volts.
    /forums/images/graemlins/usaflag.gif /forums/images/graemlins/k5.gif
     
  8. skratch

    skratch 1/2 ton status

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    [ QUOTE ]
    Be sure to go + to - and - to + or you will get a suprise w/ 24 volts.

    [/ QUOTE ]

    Actually that won't work. If you run the second battery's + to the first battery's - and the second battery's - to ground and the main battery's + to the starter, that will yeild 24V.

    If you connect both + together you just get a parallel circuit that allows twice as much amperage, not twice as much voltage. /forums/images/graemlins/smirk.gif

    I spent three years wrenching on 24V trucks and the last three in a EET program (electronic engineering technology). /forums/images/graemlins/thumb.gif

    If you want to run an isolator your gonna need to get one that has a higher rating that you alt. If you have the 105amp CS alt. then you have to get an isolator with at least a 105amp rating, and those are a tad more expensive.
     
  9. 84_Chevy_K10

    84_Chevy_K10 Banned

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    I just got me a quick disconnect, $5, and I have two batteries...just disconnect them when I'm not driving the truck.
     
  10. R72K5

    R72K5 Banned

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    good info, cool, im gonna start looking for cables and also weld up a tray for driver side

    thanks
     

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