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Dual Batteries

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by dmanblazer, Sep 5, 2004.

  1. dmanblazer

    dmanblazer 1/2 ton status

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    Years ago I had an '80 chevy 1/2 ton diesel that some one dropped a gas 350 Rocket motor in before I bought it, it still had the dual battery set up in it. And I was thinking about doing it to my '79 Blazer. Does anybody know how to do it as cheap as possible? I just dropped $5K into my engine /forums/images/graemlins/deal.gif and the wife just don't understand.
     
  2. TruckNutzDude

    TruckNutzDude 1/2 ton status

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    Welcome to CK5 /forums/images/graemlins/waytogo.gif

    First you will need a battery isolator, linky. Then, depending on where you want your batteries, you will need an auxiliary drivers side battery tray. You can get them through a company such as LMC or Chevy Duty. /forums/images/graemlins/grin.gif
     
  3. Smitty

    Smitty 1/2 ton status

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    Do you need the isolator if you're not running a winch etc.? I was thinking of adding another battery since I already have the extra tray. Figured I'd connect both positive cables and just run the spare ground to the frame or block. Now I'm not too sure.... /forums/images/graemlins/dunno.gif
     
  4. Pookster

    Pookster 1/2 ton status

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    YOu sure you need the isolator? Last time I checked the GM diesels were still a 12V system, the batteries were just connected in parallel.
     
  5. cybrfire

    cybrfire 1 ton status Vendor GMOTM Winner

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    What the isolator is there for is to prevent the batteries from discharging each other. Say for instance you keep the battery you have now and put in another. The newer one will be stronger so the weaker one will drain it and supposedly they never even out perfectly. So, in the end the batteries will kill each other. Now, on the other hand I ran duals in my last truck and never used an isolator. They lasted for years. Like mentioned above the old deisels didn't have isolators and seemed to last a long time. Then again, a friend of mine had an isolator and one would still drain down. Don't know why. Ended up ditching the isolator and just wing nutted the cables on so when its parked the batteries get disconnected. Another way to go is to use a switch which basically keeps a battery in reserve. You can drain one down and kinda jump start yourself. The cheapest way up front is just to connect pos to pos and neg to neg and maybe they will last a long time.
     
  6. TruckNutzDude

    TruckNutzDude 1/2 ton status

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    Wouldn't doubling the batteries up like that make your system 24 volts??? Last time I checked GM diesels ran on 24 volts under the hood and 12 volts inside the cab. But that's just what I think I know, since I never personally had a diesel. /forums/images/graemlins/whistling.gif
     
  7. ugly_blazer

    ugly_blazer 1/2 ton status

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    Semi trucks usually have either 3 or 4 batteries (depending on the truck) and they are all connected together and last a long time. A battery isolator would be cool if you had some type of extended current draw (radio, lights...), then you could have one "start" battery and one "accesory" battery. If you just want more cranking power then I would simply connect two batteries of the same type and age in parallel.
     
  8. Pookster

    Pookster 1/2 ton status

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    [ QUOTE ]
    Wouldn't doubling the batteries up like that make your system 24 volts??? Last time I checked GM diesels ran on 24 volts under the hood and 12 volts inside the cab. But that's just what I think I know, since I never personally had a diesel. /forums/images/graemlins/whistling.gif

    [/ QUOTE ]

    Thats only if you connect in series, and the only GM diesel that did that was the CUCV's, which had a 24V starter and NATO requirements- Other than that, the civilian 6.2 diesels all used 12V starters, just two batteries in parallel for more starting power. You can acutally run on one battery- Im guessing it was just easier for GM to add another battery than use a larger battery.
     
  9. jekbrown

    jekbrown I am CK5 Premium Member GMOTM Winner Author

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    i dont think its required, but an isolator is prolly a good idea. I mean, if you run 1 normal battery (like a diehard gold or something) and 1 deep cycle (big old yellow top optima) you don't want these things sucking juice off each other. Additionally, if heavy winching kills your deep cycle battery, you still have something to start/run your rig on.

    j
     
  10. dontoe

    dontoe 3/4 ton status GMOTM Winner

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    My remote solenoid and isolater setup. I mounted the aux battery in the back in a battery box, 1 gauge wire bumper to bumper for winching/jumping others off. [​IMG]
     
  11. dmanblazer

    dmanblazer 1/2 ton status

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    How much did that isolater cost, Dontoe?
     
  12. 82diesel

    82diesel 1/2 ton status

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    Pretty much every light truck diesel has two in parallel.
     

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