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dual batteries wireing?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by weisel, Feb 13, 2002.

  1. weisel

    weisel 1/2 ton status

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    How would I go about hooking up dual batteries in my 77 k5? I want to be able to run one down for lights, radio, other gadgets, then be able to start the truck with the other. Does anyone have this kind of setup, and how did you do it?

    No, thats not a dent in my truck's body. I call it my truck's armor.
     
  2. harry

    harry 1/2 ton status

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  3. txbartman

    txbartman 1/2 ton status

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    If you don't want to go the route of one of the isolators but rather do something similar yourself, check my webpage and go to My Jimmy Project.

    This is not as good as the Hellroaring device, but it has worked great for me.

    Once you get your dual batteries wired so they both charge and so forth, simply add a fuse panel for your secondary battery. Then, attach whatever you want to this secondary fuse panel. My alternate battery has its own fuse panel that supports my offroad lights, some interior 12V circuits (for kids gameboy and reading lights), and my radio.

    Brian
    Check out <a target="_blank" href=http://tx85gmcguy.alloffroad.com>My Jimmy</a> with all her projects!
     
  4. Ddragggon

    Ddragggon 1/2 ton status

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    sounds like you want an isolator type setup. my 77 suburban has a dual battery setup, but I don't have an isolator between them. they act as 1 big battery. heck, I probably don't even technicaly have it done right... I have the main battery up front on the battery pan where it belongs... then, from there, I have aome 6 gauge wire coming off the positive post, and traveling to the back of my truck, where I have an optima hooked to it ( positive to positive, so I retain my 12 volts...) from the optima, I have about 2 feet of 2 gauge wire going through a huge fuse, into an amp fusebox. from there, I have it going into my amps for my stereo. for the negative hookups, I have a large 4 gauge wire coming off of the battery terminal to one of the seat lugs that connects with the boddy securly. I also have the grounds from the amps running to the same screw. this gives me basicaly the same thing as one of those stupid capacitors they put in huge stereo systems, except this is more versatile. if someone needs a jump, and I can;t angle the hood to thier car, I can always just pull the rear battery, and walk it over to them. ( done it before, prolly do it again)

    like I said, probably the absolute most wrong way to really do a battery setup, but it works beautifully for my giant stereo.

    -Rich

    My truck isn't ugly, you have a skewed sense of beauty

    <font color=blue>Its a Wheelbase Thing... You Wouldn't Understand</font color=blue>
    <font color=red>CK5 SUB-culture</font color=red>
     
  5. weisel

    weisel 1/2 ton status

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    tx85gmcguy, I like your idea on your web site, but am having a little difficulty sifting through your instructions. Do you have a wiering diagram of the set up?

    No, thats not a dent in my truck's body. I call it my truck's armor.
     
  6. Strahan

    Strahan 1/2 ton status

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    &gt;this gives me basicaly the same thing as one of those stupid capacitors they put in huge stereo systems, except this is more versatile.

    The point of capacitors is the instant discharge of power. No battery can match a cap for supplying power at speed, which is why people use em so when the bass hits the amp can draw from the cap. But your setup does sound more versatile :)
     
  7. 84_Chevy_K10

    84_Chevy_K10 Banned

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    I couldn't understand it either. A schematic would be much better. I took 2 years of electronics...I understand those.

    Tim
    '84 Chevy K10, lifted, loud, fast, and 3/4 ton axles
     
  8. txbartman

    txbartman 1/2 ton status

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    I will put together a basic schematic, but here are the basics of my setup...

    Main battery neg to ground
    Secondary battery neg to ground
    Main battery hot to starter post
    Alternator to starter post
    Lead from starter post to one side of 200A continuos duty solenoid
    Secondary hot to other side of 200A continuous duty solenoid
    The solenoid is then wired to a switch

    That's really it. When the switch is thrown, the solenoid activates and connectes the circuit between the secondary batt and the starter post. Since that is a common connection of the primary battery and the alternator, all circuits are connected.

    The only "trickery" I did was in wiring the switch. Mine is a three pos switch. In the center it is off. No power to the solenoid. Batteries are independent. My secondary battery has its own set of cicuits connected to my off-road lights and stuff. I disconnect when using these components and I don't want to draw from the alternator or the main battery.

    Then the switch has two different "ON" settings. One ON setting draws power from the ignition circuit on the main battery. This is the position I normally leave it in. That way, if the vehicle is off, there is no juice to the solenoid so the batteries are disconnected. Vehicle running, connected, vehicle off, disconnected.

    The third position (other "ON" position) draws its power from the secondary battery circuits. If your main battery is dead and the switch is in the "ON" position mentioned above AND your main battery has just enough juice to throw the solenoid, the secondary battery will essentially jump your main one automatically. But what if your main battery is completed dead? You wouldn't have the juice to even power the solenoid to use the secondary battery. So, my switch has this additional ON position that draws power from the secondary battery circuits. It is an emergency position. In this position, the switch (and hence solenoid) is thrown by the secondary battery's power, the circuit is connected, and the secondary battery powers the engine. The reason this is an "emergency" position is that whenever the switch is in this position, the batteries are conncted. If the alternator is not charging (i.e. bad alternator od engine off), the two batteries are still conncted. Per the good ole electrical laws, the two connected batteries will equalize their charges. The secondary battery will be drawn down by the bad main battery. Or, if I were to run my offroad lights, I would drain both the secondary battery AND the main battery. You risk discharging both batteries and no longer having a backup.

    Hope this helps clear some up. I will get a rough schematic thrown together and on the website.

    Brian
    Check out <a target="_blank" href=http://tx85gmcguy.alloffroad.com>My Jimmy</a> with all her projects!
     

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