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Dual Alts

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by TheGeneral, Nov 19, 2001.

  1. TheGeneral

    TheGeneral 1/2 ton status

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    Anyone running dual alts. i have an 89 and it has a bracket I could probably make work, get a longer belt, but question is how it works in reference to charging another battery, and how to wire it up. Second battery for winch, compressor and such.

    If you ain't hurt, you ain't playin' hard enough.

    The General
     
  2. TheGeneral

    TheGeneral 1/2 ton status

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    anyone?

    If you ain't hurt, you ain't playin' hard enough.

    The General
     
  3. mnstr_fx

    mnstr_fx Registered Member

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    If you can mount it, you can run it. Do you have dual batteries with an isolator? If not, basically, you would wire the alternator(s) the same. Power back to the battery. The big difference will be that you are getting double the amps, (if they are the same size).

    76-82 Chevy Pickup / Blazer - K5-K10-K30
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  4. militaryblazer

    militaryblazer 1/2 ton status

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    Military Blazers and Pickups had dual 100 amp alternators and dual batteries with 6.2 diesels.

    <font color=yellow>Pics of my sold military blazer--&gt;<a target="_blank" href=http://www.geocities.com/m1009_86>http://www.geocities.com/m1009_86</a></font color=yellow>
     
  5. TheGeneral

    TheGeneral 1/2 ton status

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    again, the only question is on the wiring side of the second alt and battery. No sense wire, or just a ground of the alt (probably in mount) and the pos output to bat? Obviously the bat is ground and then your acc hooked to pos of that bat. Is that how simple it is or am I missing something. Can the alt overcharge the bat? Thanks for input.

    If you ain't hurt, you ain't playin' hard enough.

    The General
     
  6. sluggo45acp

    sluggo45acp 1/2 ton status

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    I dont know how they set up dual alternators on trucks but in aircraft you have to run a regulator(s) with a parallel circuit so both alternators split the load if not one alternator will drop off line and the other will carry all the load. (my .02)
    Butch

    <font color=red>All that is necessarry for evil to triumph is for good men to do nothing.<font color=red><font color=blue>Edmund Burke<font color=blue>
     
  7. Blue85

    Blue85 Troll Premium Member

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    The problem that you will run into is that each alternator has it's own regulator and no matter what you do, they will never want to regulate to EXACTLY the same voltage. Because of that, one will always be working harder than the other. There are at least two ways to overcome this.

    1) Run the two alternators on seperate circuits, so that one is just like it is now and the second one charges only your axuilary battery. Then wire your winch and maybe off road lights, etc., only to the secondary circuit. Now you may want to run a solenoid and/or battery isolator between the two circuits. A battery isolator is just a diode so with good current through it, it will drop more than a volt. This could be enough protection that you could use it to let the primary circuit support the secondary when winching. If your secondary battery is starting to get low, the primary is always more than a volt higher than that. Or you could let the solenoid select between the batteries for starting or hook them together. It all depends on what you want to do.

    2) Run identical alternators from a single voltage regulator. This will get almost the same current from both units. However, a regular regulator may not be able to support all of the field current for both machines, so you might need a bigger regulator then the one normally used.

    I was actually thinking about dual alts before, but I was dreaming up a way to use and A/C clutch on the secondary with a relay to kick it on only when the voltage gets below a certain threshold. That would minimize extra drag on the engine when it isn't used.

    <font color=green>There's nothing like the smell of a rich V-8 in the morning...</font color=green>
     

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