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Thread: Dual alternator addition?

  1. #1

    Dual alternator addition?

    Did a search, cannot find anything on here. Also looked through the tune file, and cannot find anything there either. Truck is a 2004 Chevy 3500 DRW, LB7 6.6 Duramax. Want to add the second alternator. They are controlled by the PCM, so I was wondering if there is something in calibration I can change to make it a dual alternator setup where the PCM controls it as such without factory programming being involved. If anyone knows if possible, and can point me to where in HPT to look, I would really appreciate it.


    Thanks for any input you can give on this!
    03 Z06 stock.......for now
    05 Siearra 5.3 daily
    I have realized that tuning is a rabbit hole. No problem diving down this hole, in fact I jumped willingly. Just want to avoid hitting every ugly rock or root on the way down it.

  2. #2
    Potential Tuner
    Join Date
    Dec 2019
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    3
    Ok, so I've recently dug into this for my Dmax van.
    Based on gmupfitter.com builder manuals, the ECM can't actually control them independently.

    Field connection is connected together - to excite the windings and let each start generating power. (gmupfitter actually shows only 1 connected to field, the 2nd apparently excites itself after spinning for a while)
    Lamp (failure) wire is connected to both so your battery dash light comes on and you know one failed.
    Power outputs are connected in parallel too. I ran each alternator to each battery to let voltage drop through wiring separate them a little. But they're both regulating to 14.80v when not connected to each other so I don't suspect issues.

    Hooking this up in my van this week, I'll report back after some test drives

  3. #3
    Potential Tuner
    Join Date
    Mar 2021
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    1
    what are the results from the dual alt setup?

  4. #4
    Potential Tuner
    Join Date
    Dec 2019
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    3
    Quote Originally Posted by cloud surfer View Post
    what are the results from the dual alt setup?
    hey, sorry for the delay.

    Been running duals for for a few months now. All wires in parallel. no issues so far!