Charging system problem

Discussion in 'Electrical' started by chester1957, Jun 9, 2010.

  1. chester1957

    chester1957 Member

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    2002 Road King, the bike is not charging. I checked the stator, it has .2 ohms pin to pin, 0 ohms pins to ground. It has 26 vac at idle, and increases to 72 vac @ about 3,000 rpm, so I replaced the voltage regulator. Still does not charge. I have replaced more than a few H-D charging systems in my day and never run into this problem.
    I read on one forum, that some have found stators that passed the above test and were still bad under load. Anyone run into one of these or am I missing something else that could be the problem.
     
  2. Hoople

    Hoople Account Removed

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    Chester, those are very good AC voltage readings and your correct about the loading of the stator.

    Since you have a New regulator, you may want to try is this. Take a pair of very thin sewing needles and push 1 through each of the stator wires going to the regulator. Hook up the stator to the regulator just like it is normally is. Hook you AC volt meter to the two "Tap" needles.
    What I am want to see is the AC voltage while under a load. Start the bike and see what the stator output is while under a load.

    And please, don't short the two needles to each other! :p:p
     
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  3. TQuentin1

    TQuentin1 Well-Known Member Staff Member Moderator

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    Another quick test on the stator is to open up the derby cover and take a sniff. If it smells burnt, your stator has probably fried some coils. I had this happen a number of times where the stator was still putting out good Vac numbers, but was toast!

    TQ
     
  4. chester1957

    chester1957 Member

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    Both great suggestions, I took a sniff of the primary and it doesn't smell too bad (I have smell burnt ones that the second you open up the primary you could smell it) this ain't that bad.
    I'm going to try Hoople's suggestion.
    Thank you Gentlemen for your time.

    In my haste, I put the old regulator back on, thought what the heck I'll try Hopple's suggestion, no change. Put the new regulator on, tried Hoople's suggestion and I got less than 1 volt anywhere thru the rpm range. Thanks a bunch Hoople and TQ.

    I took the rotor off and found a snap ring that holds the chain shoe on the bracket attached across two magnets inside the rotor. There is no damage to the rotor and can see no sign of damage to the stator. Would anyone have a guess as to whether that could cause the alternator to not have any output? I would hate to put it all back together, have it not work, or should I just go ahead and replace the stator and be done with it?
    Thanks for watching.
     
    Last edited by a moderator: Jun 10, 2010
  5. TQuentin1

    TQuentin1 Well-Known Member Staff Member Moderator

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  6. chester1957

    chester1957 Member

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    I did all those before posting, threw a new stator in it this morning and all is good. The tip about the tap needles and checking vac under load did the trick. Like I posted, just reading the output with no load was throwing me for a loop, as this is the first time I've run into one that threw good numbers with the regulator unhooked. Live and learn.

    Again thank you and Hoople for taking the time to help out.
     
  7. NEWHD74FAN

    NEWHD74FAN Experienced Member Retired Moderators

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    AC voltage check for the stator under load, (sniff test is easier) to determine condition. Naturally voltage with no load (load resistance or current flow) will give you the highest voltage (pressure) reading, which is false. Like reading your battery voltage 12.6V, with unloaded battery, the surface charge can make a battery fresh of the charger to read 13.5 to 14V but minute you put a load on it, it will drop to 12.6 and drop slowly as more current flows out of it.
     
  8. rtbrannon

    rtbrannon Member

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    what should you read on the two needles