My brakes work, but my battery doesn't charge :(

Discussion in 'FJ25 Owners Group' started by foxfab, Oct 31, 2005.

  1. foxfab

    foxfab

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    Well, on the way home from this year's Fall Gathering, my 25 decided to stop charging. I barely made it home on battery power alone fortunately.

    So, I dove into the problem by purchasing a new mid 50's Chevrolet voltage regulator specifically for Chevy trucks with generators, a digital multi-meter, and our trusty wiring diagram. Yesterday, I finally got to sit down and try to hook it up. It is marked differently than the Toyota regulator, so I had to dig into the wiring diagram to figure out what wire goes where. There are basically 4 terminals with 5 wires. Ground (to the generator casing), (BATT) Battery, idiot light (comes off the Armature), (A) Armature, and (F) Field. The generator is marked with the A and F if you scrape the residue off of the casing.

    So, I have everything hooked up as I think it should be. But my idiot light is still on. I am pretty sure that it is charging though. I put a meter across the battery while the truck is running and get 12.15 volts. When I turn the lights on, the reading drops to 11.75 volts and stays there. If I turn the lights on, it climbs back to 12.15V again. I am not sure on how to check the output of the generator though. I metered it a few different ways and the only way I get voltage looks like itsputting out 3V or so regardless of the engine RPM.

    Fortunately, I also have a rebuilt generator, so I swapped that in and got the same readings +/- a volt and the idiot light still stays on.

    Maybe the Chevy voltage regulator that I chose isn't allowing enough current through to satisfy the idiot light? Or is it really not charging as it should still?

    I'm stumped. Thoughts?
     
  2. Living in the Past

    Living in the Past SILVER Star

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    I would think that the voltage regulator should put out higher voltage than 12 volts. On the new vehicles it's more like 18 volts. I would have someone who using a generator check the voltage. I can check my but you will have to wait two weeks before I get a change. Why not just go over to Jim's garage and borrow one of his voltage regulators. Take the it off the orange one (#48) he won't miss that one for years. :rolleyes:

    John
     
  3. foxfab

    foxfab

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    I know an alternator puts out 14.5 + or so volts, but I dont think that generators work that way. More old school low tech.

    The orange one was converted to a Chevy one-wire alternator :)
     
  4. Living in the Past

    Living in the Past SILVER Star

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    So mike what's the belt size with the generator? I have one that is set up with the one wire alternator but the voltage regulator is still there with the complete wiring harness. The PO said he had it changed because he was tired of the brushes wearing out. Of course he was using KC Daylights which probably didn't help. So if you get me the belt size I will pick one up and install a generator and we can compare notes. I got the oil light on the dash working and I would like go get the charging light working too. You know the idiot lights. I think it's funny the 04 4Runner has more lights than guages. So does this mean the 25s are coming back into style. You know, you wait long enough and everything comes back in style.


    John
     
  5. Cruiser_Nerd

    Cruiser_Nerd That 25 Guy. Moderator

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  6. Landpimp

    Landpimp GOLD Star

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    swap out the generator for a alternator......I am so happy I did(on my 45LV)
     
  7. foxfab

    foxfab

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    eeeewww, you mean add a non FJ25 part to my baby? Only as a last resort :)
     
  8. foxfab

    foxfab

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    wow, I can't wait to try out the test on polarization to see the generator spin by itself. In the halloween spirit, I hope it spits out split pea soup too!!! :)
     
  9. Cruiser_Nerd

    Cruiser_Nerd That 25 Guy. Moderator

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    Ummmm, I've never done that one before........

    Let me know how it works out. :doh:

    I've done the other two though. ;)
     
  10. Living in the Past

    Living in the Past SILVER Star

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    Quote: Landpimp swap out the generator for a alternator......I am so happy I did(on my 45LV)


    John if I don't change back to a generator I'll miss having to check the polarization of the generator.
    See all the fun your missing by changing out by replacing the generator with an alternator.


    Mike just remember that all wires have smoke in them and the secret is not letting the smoke out.


    John
     
  11. foxfab

    foxfab

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    I didnt make it to work today because I thought my charging issues were done, but I was wrong.

    She started spuddering 1/2 way there and I decidxed to turn around. Once I got home, I started the diagnostics from the above web sites. I did get the generator to turn over by itself, but once grounded, I still couldnt get voltage out of it. Time to send it to a different shop.
     
  12. foxfab

    foxfab

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    Update on my charging issues. McKnight Generator has my two generators, a green starter, my new delco voltage regulator and the two old ND regulators. Both ND regs are bad. And, apparently there are two types of "circuits" when it comes to generators. An A and a B circuit. Chevy uses an A circuit. Ford uses a B circuit. Toyota also uses a B circuit, so my Delco voltage regulator wouldnt work with the B circuit generator. So, I went to Napa's website and have a MPEVR412SB Voltage Regulator on order which is a 12V 30 amp Ford voltage regulartor for trucks with generators. Years were 1956 to 1964. We'll see if this solves everything.
     
  13. foxfab

    foxfab

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    Charging issue SOLVED!!!

    Everything arrived safe and sound and I had a little time this AM to stick in my generator and new voltage regulator. IT WORKS!!! :cool:

    [​IMG]

    [​IMG]

    The holes do not line up so you will be drilling if you do this mod. But with careful placement, the old holes will be covered on the firewall side.

    Case Closed!
     
  14. zebrabeefj40

    zebrabeefj40

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    So did today turn into take the 25 to work day?

    Nick
     
  15. foxfab

    foxfab

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    It would have if I had a soft top or it stopped raining :D
     
  16. Cruiser_Nerd

    Cruiser_Nerd That 25 Guy. Moderator

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    Since it's raining out............you've got time to gut that regulator and transplant it int the original can. :D
     
  17. foxfab

    foxfab

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    I'll put em side by side and see if it can be done. :D

     
  18. warrior_1515

    warrior_1515

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  19. foxfab

    foxfab

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    I dont think that is an original, it might be an older Chevy or Ford generator. They are similar in size and shape. See if you can get pics of the top of it where the terminals are. Ther should be a Denso tag in front of the terminals.
     
  20. destin

    destin

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    Hey fabfox

    How do you know if you generator needs a A-circuit or a b-crircuit voltage regulator>?

    Thanks man!

    Destin
     
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