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High output alternator

Discussion in 'Electrical & Audio' started by 1973c10, Oct 19, 2019.

  1. 1973c10

    1973c10 Full Access Member

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    Hey all


    I have a one wire 65 amp alternator now
    and am looking to upgrade to a 150 Amps at Idle / 220 Amps at Full Output,
    right now it is wired from the post on the alternator into the fuse block
    if I upgrade and go from the post on the alternator directly to the battery
    what size wire should I use
     
  2. C10MixMaster

    C10MixMaster Full Access Member

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    c778d20295451a545fbcccad2598cf18.jpg

    looks like 4GA
     
    Dan Miller, Doppleganger and Snoots like this.
  3. 1973c10

    1973c10 Full Access Member

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  4. 1973c10

    1973c10 Full Access Member

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    is there any issue with running that high of amp alternator
     
  5. Matt69olds

    Matt69olds Full Access Member

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    Why do you need that much capacity? There is no problem running that big alternator, just make sure the charge wire is big enough to handle the current
     
  6. 1973c10

    1973c10 Full Access Member

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    2 electric fans , large sound system , AC , halogen headlight and so on
    if I use a amperage calculator its about 152 amps
    Driving at night things start going dim and the voltage drops it under 12v

    I was going to run 4 GA with a fuse from the post on the alternator directly to the battery
    about a 2 foot wire
     
  7. Frankenchevy

    Frankenchevy . Supporting Member

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    I have a 175 amp Tuff Stuff alternator and settled on 2/0 wire after speaking with the manufacturer.
     
  8. gotyourgoat

    gotyourgoat Full Access Member

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    Curious to know if an alternator throwing more juice is going to help with the lighting without wiring upgrades.

    Wiring upgrades to the lights that is.
     
  9. 1973c10

    1973c10 Full Access Member

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    We will see

    I installed a new complete painless wiring harness about 3 years ago
    I have no problems until night driving and after about an hour or so the voltage starts to drop
    and stuff starts to dim
     
  10. ali_c20

    ali_c20 Full Access Member

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    Are you running a heavy duty wiring harness with relays for the lights?
     
  11. MikeB

    MikeB Full Access Member

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    What is the voltage at the battery and headlights when they start to get dim?

    Have you used a DC current clamp on the fuse panel feed wire to measure the current draw with all accessories running?
     
  12. 1973c10

    1973c10 Full Access Member

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    Yes I am
     
  13. 1973c10

    1973c10 Full Access Member

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    12.5 volts at the battery and headlights when they start to get dim

    No I have not tried a DC current clamp on the fuse panel feed wire to measure the current draw with all accessories running
     
    Last edited: Oct 21, 2019
  14. 1973c10

    1973c10 Full Access Member

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    This is why I think I am pulling to many amps
    My current alternator is 65 amps
    I have 2 Electric Cooling Fans 15 amps each ( 30 amps total )
    halogen headlight 18 amps
    Instrument Panel 2 amps
    Lamps, License Plate 1 amps
    Lamps, Side Marker 3 amps
    Lamps, Tail 5 amps
    CD/Tuner with Amp 40 amps
    Ignition 10 amps
    Electric Fuel Pump 6 amps
    plus thing I don't run all the time like AC , Heater Defroster , Dome Light , Back-Up Lamps and so on
     
  15. MikeB

    MikeB Full Access Member

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    You forgot brake lights.:)

    Yeah, a 65 amp alternator is not enough for that load, and could certainly be your problem. But I think a 140 or even 120 amp model should be more than enough. And if you can mange routing the large 4 gauge charging wire, you will have zero voltage drop from alternator to battery.
    I haven't done car stereos since the 80s, but I have to wonder how much volume it would take for yours to draw 40 amps. Would sure like to see pictures of the installation.
     
    Last edited: Oct 21, 2019

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