Page 2 of 2 FirstFirst 12
Results 11 to 16 of 16

Thread: 2nd alternator and battery

  1. #11
    Newbie
    Join Date
    Mar 2008
    Location
    Kankakee, IL
    Posts
    6
    Quote Originally Posted by ozzy71 View Post
    3-wire is the way to go when adding a second alternator... keep this in mind though.. you will be dumping MPG like crazy.

    That said-- let me try to help you instead of redirect you.

    Which GM 3-wire alternator do you have? Or-- Exactly what car did it come out of?


    AC Delco Rating Clocking Delco Part # *Lester catalog Pt#
    10SI 63amps 3:00 321-39 7127-3
    10SI 63amps 9:00 321-41 7127-9
    10SI 63amps 12:00 321-43 7127-12
    10SI 63amps 6:00 321-135 7127-6
    12SI 94amps 3:00 321-266 7294-3
    12SI 94amps 9:00 321-269 7294-9
    12SI 94amps 12:00 --------- 7294-12
    12SI 78amps 3:00 321-247 or 321-357 278-3
    12SI 78amps 9:00 321-244 7278-9
    12SI 78amps 12:00 321-249 or 321-254 7278-12
    Thanks man, I believe it was a 87 caddy deville.
    blazin97
    1997 Chevy Blazer with 2 Massive p1000.1(1000 rms @ 1ohm) and 4 Massive RW 12"(400rms, 800 max)

  2. #12
    cheap custom title JC-S60's Avatar
    Join Date
    Mar 2004
    Location
    Ghent - Belgium
    Posts
    1,863
    You will need a voltage regulator for the separate cirquit, so the battery doesn't get overcharged (unless it's already integrated into the alternator).

    Good luck!

    Joachim

  3. #13
    Newbie ozzy71's Avatar
    Join Date
    Feb 2008
    Location
    Atlanta
    Posts
    28
    I have never seen a 3-wire alternator that is not internally regulated.

  4. #14
    Newbie
    Join Date
    Mar 2008
    Location
    Kankakee, IL
    Posts
    6
    Quote Originally Posted by ozzy71 View Post
    I have never seen a 3-wire alternator that is not internally regulated.
    How do I know if its internally regulated? If it helps it of a mid 80's Caddy. Its already mounted on the truck so i can test whatever
    Thanks
    blazin97
    1997 Chevy Blazer with 2 Massive p1000.1(1000 rms @ 1ohm) and 4 Massive RW 12"(400rms, 800 max)

  5. #15
    Newbie ozzy71's Avatar
    Join Date
    Feb 2008
    Location
    Atlanta
    Posts
    28

    more info

    If this unit indeed came off of a 1987 deville:

    It is a 120amp unit and it is externally regulated.

    Here are some photos of things to look for:

    3-wire connector:

    Rear-photo of alternator

    photo of external regulator

    Your regulator may already be on your alternator. Any chance you can upload a photo of your alternator?? I mostly need the rear of the unit.

    Also, do you already have the 3-wire pigtail? Keep in mind the photos I am showing you are from an autoparts store's online information-- so I need you to verify that it is correct.

    I built a battery isolator and installed a 2nd battery in my shoebox scion for $10... it works perfectly... and is easy to do.
    Attached Images Attached Images    

  6. #16
    Constant Bitrate
    Join Date
    Mar 2008
    Posts
    162
    How about just upgrading your current alternator?

    Get a high output alternator and replace your stock one.

    Then rip out that wire you did for the big 3 and use 0awg.

    Then get an Optima battery to replace your current one.


    That should help out quite a bit. If you STILL get dimming, then think about maybe a second alt. I had around 3k watts worth of amp in my old car and it did not dim using what I just described above.

    I had a 200 amp alternator.

Page 2 of 2 FirstFirst 12

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •