Charging Problem

Discussion in 'Touring Models' started by olddude, Dec 17, 2008.

  1. olddude

    olddude Member

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    I'm having a charging system problem I think, at 3,000 rpm and above the volt meter will drop from 14 volts to 12 volts for a few seconds than goes back to 14. If I keep the rpms above 3,000 it will continue to fluculate. Below 3,000 it is fine. I have checked it with a volt meter, the battery is fully charged, but the voltage fluculation happens even when the bike is stationary. Any ideas.
     
  2. glider

    glider Veteran Member

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  3. olddude

    olddude Member

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    Thanks glider, got a couple of days off and it's raining here in the desert of SoCal so I guess I know what I will be doing. Thanks again
     
  4. glider

    glider Veteran Member

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    If you don't find anything obvious, have the battery load tested.
     
  5. glider

    glider Veteran Member

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    That's a variation of "they all do that" :D
     
  6. BUBBIE

    BUBBIE Well-Known Member

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    I was JUST WONDERING what would it do if you allow BATTERY to discharge a little........ Maybe Leave the lights on for 5 min and then start and test voltage out put see what gives.......... I would imagine the charge should go up and stay there...... If not I don't know........

    PLEASE let us know what you find.....THESE things teach (us) the readers so we can help our selves and then help the OTHERS!

    signed....BUBBIE
     
  7. olddude

    olddude Member

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    I plan on working on it tomorrow, and will let everyone know if I find the promlem. Thanks again for all of the input.
     
  8. NEWHD74FAN

    NEWHD74FAN Experienced Member Retired Moderators

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    Glider is exactly right, if voltage is fluctuating within 10V to 14.5 you probably have a bad connection because the extreme low voltage limit and high voltage limit are controlled solidly by the battery and regulator respectively. Also check your digital meter, test probes and dare I say the battery in your meter...? as well as the bikes high current cable connections. Analog meters have "dampened" movements that do not fluctuate fast when you connect, and the battery inside will not affect your readings, (is for resistance or "ohms" testing) if you are using "old school" equipment.:newsmile030:

    Charging voltage directly from the alternator (basically an AC generator with diodes) makes DC Direct Current to power your battery and the DC powered accessories...using the battery power storage only as a reserve for starting and initial running of accessories if the bike is off or idling. :)

    Your Harley runs primarily off the alternator once RPMs are slightly above idle...at say 1200RPM it would put out 14V and at max RPM would try to put out 20V if not limited/stablized by the regulator on the high end to typically 14.5V-15V, the battery is like a big "volltage bucket" storing a surface charge on top to deliver 12V steady (between 10-12V with up to 200A of current flow or better) when starting or if the charge voltage falls below 12.8V nominal. Having lights on for 5 or 10 minutes is really not very much to drop the battery voltage substantially. :28:

    After you have cleaned all the power connections and run the load test Glider referred to you should pretty much have a direction to go. Good Luck...:D
     
  9. TQuentin1

    TQuentin1 Well-Known Member Staff Member Moderator

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    What the guys are suggesting is to take off the battery cables and clean both mating surfaces with a wire brush or equivalent to make sure you have a good connection. You can coat the terminals with dielectric lube thereafter to try and keep them from corroding.

    Also check all your grounds to make sure all are tight. If you have the time and interest, you might take these loose and do the same as the battery ends.

    Inspect the cables carefully to make sure they are not corroded close to the ends.

    This eliminates poor connections as the reason for your problem. Fire the bike up and try wobblin the cables to see if you get any fluctuation.

    After doing the tests that Glider suggested above, if you find everything OK, run around and see if the symptoms are still there. If so, get the battery checked out at the auto parts place. If it is the battery, check these folks:

    Odyssey Batteries | Battery Specifications

    These are tough batteries.

    If it is the charging system, see the self-help section. Plenty of help there.

    TQ