Charging System Is Low

Discussion in 'Electrical' started by Fossil, Jul 18, 2008.

  1. Fossil

    Fossil Active Member

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    I hope some one out there can help me. I have a 1988 FLHS and it burned up the stator and rectifier. I put in the upgraded 32 amp charging system. It worked for a while but one day it just clicked and it was dead. I got a new battery and put it in and it ran nice but I can tell by the lights and turn signals that the battery is getting low. Checked it our and only 12.5 volts were going into the battery. A mechanic checked out the rectifier and stator and recommended a new stator. Well, I put one in and got good readings but in a couple of weeks the same low readings again. Another stator and still low readings. What else can I check? The stator is low voltage at 12.5 volts at the battery. The rectifier tests good. Can the battery be refusing a full charge? Fossil
     
  2. glider

    glider Veteran Member

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    It sounds like you replaced the battery so I would look through the wiring harness and ground wires for a bad connection.
     
  3. TQuentin1

    TQuentin1 Well-Known Member Staff Member Moderator

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    Are you checking this yourself? If so, go to Glider's self help section on electrical stuff and follow those procedures. Especially the VR bleed back. Then check the stator for grounded coils (ohm meter). Make sure the alternator is putting out about 20 Vac/1000 rpm. If your charging system all checks out, and you have made sure your grounds are tight and no broken wires, pull the battery and take it to the auto parts place for testing.

    Good luck.

    TQ
     
  4. Fossil

    Fossil Active Member

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    Thanks guys for the tips. I had a qualified mechanic put the new stator in and he said it was putting out too little just like the last one did. Hmmm, new rectifier, second stator and every thing is doing the same thing. The battery checked out good on a load test at the dealers. Today I spent a lot of time checking grounds, connections, battery terminals, etc. A mechanic at the dealership suggested that I check out the rectifier connection to the main circuit breaker. I soldered that lug and wire brushed all connections and terminals. The battery shows 12.7 at idle but when I rev it up it shows up to 14 volts. The crazy thing is that it won't read the same reading twice but it does some times read good. I will check all grounds again. Fossil
     
  5. dangerdan

    dangerdan Junior Member

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    I have 3 questions

    1) Was the voltage regulator ever tested ? See no mention of that.
    2) Were the magnets in the Rotor ever inspected ? Possible misallignment.
    3) Did you ohm out each wire ? Possible intermit open.

    Forgot one thing: When the compensator nut got removed ,was an air gun used ? I think there was something in the self help that indicated that vibrations could damage the magnets in the rotor.
     
  6. Fossil

    Fossil Active Member

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    Last night I had a volt meter on the battery with the engine idling. When I reved it up to 3000 RPM the reading was first 12.5. Read the same at idle. Then I reved it back up to 3000 RPM and it read slowly up to 15 volts. I repeated it and it was back to 12.5 volts. Why such an inconsistent reading? The battery was tested under load and declared good. The original rectifier and stator burned and melted themselves together at the plugs. I rode my bike today for 70 miles and at that time it wouldn't start and I had to be push started. It ran home but all I had in the battery was 11.75 volts. I originally had the old 22 amp alternator replaced with an Accel 32 amp stator and rectifier. It first showed it was putting out but a couple of weeks later it was down on voltage. The stator was replaced and it still won't put out enough juice. It has to be some thing that hasn't been changed and perhaps the magnets are out of aline. The magnets were taken off and put back on three times with an impact. Fossil
     
  7. Bud White

    Bud White Well-Known Member Retired Moderators

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    you can knock the magnetism out of them using a impact

    roping the rotor or other shock can also do it .. and also know the magnets loose or crack them to come free and cause all kinds of trouble later
     
  8. Fisher

    Fisher Account Removed

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    What is the A/C output at the plug?Low A/C output at the stator plug indicates a bad rotor.Don't beat on rotors.It is bad.
     
  9. TQuentin1

    TQuentin1 Well-Known Member Staff Member Moderator

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    You should be getting about 20 Vac/1,000 rpm at the stator plug at least according to my service manual.

    When you changed out the alternator system, you changed both the stator and the rotor as a set, right? And the voltage regulator was for that new rotor-stator combination?

    TQ
     
  10. Fossil

    Fossil Active Member

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    The first change was a set of voltage regulator and stator. Things read at a minimum but quit putting enough voltage in to keep the battery up. Then a second stator was put in and it doesn't put enough voltage out to keep the battery up. The battery was checked for load and declared good and is only three months old. I had assumed that the rotor had been changed the first time but found out that it still has the original rotor. That seems to be the constant on all the work being done. I think Dangerdan suggested checking that out. I will put one in this week. Wish me luck. Fossil