Register now to get rid of these ads!

Hot Rods Overcharging my battery?

Discussion in 'The Hokey Ass Message Board' started by Bigstar, Sep 25, 2015.

  1. Bigstar
    Joined: Mar 27, 2010
    Posts: 183

    Bigstar
    Member
    from Austin

    I've been smelling a STRONG sulfur smell the last couple times I have driven my '57 and I couldn't pinpoint the source. Tonight I drove a good ways and when I turned off the truck I could hear a sizzle… I traced the sound to the battery. It was smoking and bubbling. Not good. I just replaced the alternator a couple weeks ago with the one that Autozone recommended. Any ideas?
     
  2. squirrel
    Joined: Sep 23, 2004
    Posts: 49,259

    squirrel
    Member

    sure, show us a picture of the alternator, and maybe describe how it's wired up. Could be that something is amiss.
     
  3. got a volt meter installed in/under the dash? If so,what's it reading going down the road?
     
  4. Bigstar
    Joined: Mar 27, 2010
    Posts: 183

    Bigstar
    Member
    from Austin

    Thank you. I wired it up the same as the one that came off. This is a Pontiac 301 motor.
     

    Attached Files:


  5. woodz
    Joined: Feb 23, 2010
    Posts: 517

    woodz
    Member

    I hope thats not the volt meter reading when its running. :)
    What does it show when you are driving down the road? Shouldnt ever be any more then 14.8V. If it does then you have a regulator problem. Is your regulator internal or external?
     
    loudbang likes this.
  6. Bigstar
    Joined: Mar 27, 2010
    Posts: 183

    Bigstar
    Member
    from Austin

    So after looking around online I'm thinking the genius at the auto parts store sold me a high output alternator that is the wrong application for my engine… maybe it's my fault for not knowing what alternator I needed instead of trusting the Autozone employee.. :) I should go swap it out I'm thinking…

    https://www.powerbastards.com/proddetail.asp?prod=7127-9-220-HD10-67
     
  7. squirrel
    Joined: Sep 23, 2004
    Posts: 49,259

    squirrel
    Member

    A higher output alternator can provide more current when needed, but if it's working properly, it will still run at the proper voltage. That's a 63 amp alternator, which should be fine for your truck.

    but also, how old is the battery?

    You really need to see what the voltage is when the engine is running at a fast idle, as he said it should be between 13 and 15 volts. If it's higher, then the internal voltage regulator is probably messed up, or there is some other internal problem with the alternator, and you need to replace it.
     
    loudbang likes this.
  8. 325w
    Joined: Feb 18, 2008
    Posts: 5,606

    325w
    ALLIANCE MEMBER

    The alternator plug say internal reg. I pay a little more for my alternators. I buy from a local rebuilder.
     
  9. Bigstar
    Joined: Mar 27, 2010
    Posts: 183

    Bigstar
    Member
    from Austin

    The gauge pegs out at 16 volts. When I turn the truck on it pegs at 16 same as when I'm driving down the road. I really didn't pay that much attention to it because it is all new and I just assumed was working correctly. So should I swap the alternator out for a lower voltage model?
     
  10. squirrel
    Joined: Sep 23, 2004
    Posts: 49,259

    squirrel
    Member

    the alternator is defective. It is the right model. you just need to get one that works.

    first though, make sure the red wire on the plug is connected to the red wire that is on the screw terminal.
     
    volvobrynk likes this.
  11. Years ago I replaced the alternator on my Corvette with a "rebuilt" one from a parts house. Immediately upon starting the car the volt meter pegged and the dash lights lit up so bright they almost blinded me. Obviously the internal regulator was bad. I took it back and got another one and no problem after that. I think you have the same problem.
     
    loudbang likes this.
  12. onetrickpony
    Joined: Sep 21, 2010
    Posts: 513

    onetrickpony
    Member
    from Texas

    A charging system that is working correctly will only put out enough voltage/amperage/wattage to run whatever is using electricity and a little extra to keep the battery charged. It can't put out too much and boil the battery unless something is wrong.

    The voltmeter should never peg out like you are seeing under normal conditions. Take that alternator back to the store for testing and most likely replacement unless you have miss wired it. The type of alternator you have has a tab for testing that can bypass the regulator making it do what you are seeing. My guess is that the test tab is grounded out somehow internally. Search "GM alternator full field test" for details.
     
  13. Don's Hot Rods
    Joined: Oct 7, 2005
    Posts: 8,319

    Don's Hot Rods
    Member
    from florida

    Doesn't matter if it is high output or not, as long as the regulator is working properly. Sounds like yours is not.

    Alternators from your local parts store are a crap shoot, I have had them fail right out of the box, especially the rebuilt ones. Swap it out and see what the next one does.

    Don
     
    loudbang likes this.
  14. 29moonshine
    Joined: Dec 30, 2006
    Posts: 1,319

    29moonshine
    Member

    i got 3 from orilleys before i got one that worked right
     
  15. Don's Hot Rods
    Joined: Oct 7, 2005
    Posts: 8,319

    Don's Hot Rods
    Member
    from florida


    Me too, but from another parts chain. Over about 6 months 3 of them failed and I took them back. The "expert" behind the counter said "Ok, I will give you one more, but that is it, you have something wrong with your car !" So I told him to test the new one on his machine before giving it to me.

    He took one off the shelf, tested it and set it aside. Then he pulled down one more and tested it, set it aside. Finally, on the third attempt, he got one that would work right. As he handed it to me, I said "So what was that you were saying about something being wrong with my car ??" :rolleyes:

    Rebuilders fix the most obvious problem when they rebuild them and stop there. There can be secondary problems that they miss. Now I only buy brand new parts, but sometimes even those are bad out of the box.

    Don
     
    lothiandon1940 likes this.
  16. It should charge between 14.1 and 14.5 volts. Check all grounds while you're at it.

    I use local shops to do my starters and other electrics. So they know me and so far have never sold me something bad. One old guy did my stock car starters and no matter how hot the engine got, it always started.
     
  17. Check the ground to the battery. If it is loose the alt will put out more voltage and boil the battery.
     
  18. olscrounger
    Joined: Feb 23, 2008
    Posts: 4,318

    olscrounger
    ALLIANCE MEMBER

    As many have said, bad alternators right out of the box. I gave up on those and buy new ones or take them up the hill to a reliable local rebuilder-an older guy with a one man shop-knows his stuff. Have had good luck with Powermaster alternators.
     
    lothiandon1940 likes this.
  19. squirrel
    Joined: Sep 23, 2004
    Posts: 49,259

    squirrel
    Member

    I'm running the older 1960s style alternators with the external regulator on a couple of mine...using old used regulators...they seem to do fine.

    Maybe I'm just lucky
     
  20. Bigstar
    Joined: Mar 27, 2010
    Posts: 183

    Bigstar
    Member
    from Austin

    I went back to Autozone and swapped the alternator out for a model # 7127-12M that puts out 43 amps instead of 63 amps like the one I had. They gave me the wrong one the other day. The one I had was rated for heavy trucks and equipment. I will put some miles on it tomorrow and see...
     
  21. stimpy
    Joined: Apr 16, 2006
    Posts: 3,547

    stimpy

    that and you know electronics , to some electronics are a mystery as is something you cannot see , to people like you or my dad ( also A EE ) its second nature .. to people like me I tend to burn up a few bulbs and exploded a few others before I got the hang of it ..
     
  22. stimpy
    Joined: Apr 16, 2006
    Posts: 3,547

    stimpy

    amps has nothing to do with the the voltage it puts out , the regulator was bad in the old one causing it to stay on , kind of like a broken light switch . if your battery has a problem keeping up then you will need the higher amp unit . but if your a bare basic ( lights heat only , radio ( am /fm no amps ) you should get by with the smaller unit . just remember you will have to run the vehicle 10 -15 minutes per start to keep it charged up .
     
  23. verde742
    Joined: Aug 11, 2010
    Posts: 5,697

    verde742
    ALLIANCE MEMBER
    1. a veteran died today

    I am amazed they will "work" with you, on electrical parts, no matter what the circumstances..

    They have signs all over " No return on electrical parts" (where I live, NAPA, O'Reilly's, Autozone. Joe the Rebuilder,") and others.
     
  24. stimpy
    Joined: Apr 16, 2006
    Posts: 3,547

    stimpy

    ussually thats meant for small things like sensors ,relays and switches , you wouldn't believe how many people try to "rent or borrow" a part to see if that is the cause of there problems instead of knowing what to look for or how to test the part . and we have had a few that tried to pass off the old dead part as the just bought one and get a refund on it ..
     
  25. verde742
    Joined: Aug 11, 2010
    Posts: 5,697

    verde742
    ALLIANCE MEMBER
    1. a veteran died today

    damn, "other people's kids " !!!!
     
  26. squirrel
    Joined: Sep 23, 2004
    Posts: 49,259

    squirrel
    Member

    A return isn't the same as honoring a warranty.

    and yeah, the new alternator working properly has nothing to do with the current rating. It has to do with having a good voltage regulator inside of it.
     
    lothiandon1940 likes this.
  27. Bigstar
    Joined: Mar 27, 2010
    Posts: 183

    Bigstar
    Member
    from Austin

    I am a novice when it comes to electric. The guys at the parts store didn't know much more than me but we tested the voltage with the other alternator on and it was right at 16 and with the new one it was right at 14. I will run this one for a few days and see… Thanks for the help
     
  28. squirrel
    Joined: Sep 23, 2004
    Posts: 49,259

    squirrel
    Member

    Some of us answering your questions are not novices with electric stuff....we've been through this many times.
     
    deto and lothiandon1940 like this.
  29. 49ratfink
    Joined: Feb 8, 2004
    Posts: 18,082

    49ratfink
    Member
    from California

    you first mistake was going to Auto Zone
     
  30. I worked at one of those discount auto parts stores for a while.
    NEVER leave the store with a rebuilt alternator or starter without them checking it out of the box first.
    Like others have stated, we have had lots of them bad right out of the box. When they rebuild one, they only replace the bad parts and clean the rest, its not really rebuilt, its overhauled. And sometimes they have the wrong unit in the box. Do not trust the store.
     
    lothiandon1940 likes this.

Share This Page

Register now to get rid of these ads!

Archive

Copyright © 1995-2021 The Jalopy Journal: Steal our stuff, we'll kick your teeth in. Terms of Service. Privacy Policy.

Atomic Industry
Forum software by XenForo™ ©2010-2014 XenForo Ltd.