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Thread: Electrical Issue

  1. #16
    R100GS, '89 Guenther's Avatar
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    With the engine off and ignition on what is the state of the charging light? On/dim/off?

    Did you check the volts at the battery while riding? I am curious about what happens with the charging voltage when the light comes on bright. If the voltage stays ca. 13.5 V there might be a problem with the connection of that light bulb and nothing else.

    /Guenther

  2. #17
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    Yes I checked the charging while revving (but not riding since I don't have a dash voltmeter) and got 13-7-13.8 volts at 1500 rpm. Is this a good number of those rpms?

  3. #18
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    Quote Originally Posted by 174713 View Post
    Yes I checked the charging while revving (but not riding since I don't have a dash voltmeter) and got 13-7-13.8 volts at 1500 rpm. Is this a good number of those rpms?
    Those sound like good numbers...hopefully it will edge a bit higher towards 14v as the RPM gets above say 2500 or 3000.
    Kurt -- Forum Administrator ---> Resources and Links Thread <---
    '78 R100/7 & '69 R69S & '52 R25/2
    mine-ineye-deatheah-pielayah-jooa-kalayus. oolah-minane-hay-meeriah-kal-oyus-algay-a-thaykin', buddy!

  4. #19
    R100GS, '89 Guenther's Avatar
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    When the charging light is off and the voltage reads >13+ Volts we have a working system and there's close to no chance to identify a fault...right? So, you have to catch the fault at its act means, you have to check the voltage when the charging light comes on. If that can only be produced while riding then you have to setup your voltmeter for that.

    If the outcome of this test would show that the light comes on but the voltage still shows >13+ Volts it indicates the charging system is Ok and the problem is either with the charging light's connection or even the battery. On the other hand if the voltage drops significantly ( <10V) while the light comes on then it points to the diode board (diodes or its connections).

    /Guenther

  5. #20
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    Since I've removed, cleaned and used dielectric grease on all connections and replaced the battery and diode board I'm leaning toward the dash light connection. Thanks for all the help.

  6. #21
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    Quote Originally Posted by 174713 View Post
    Since I've removed, cleaned and used dielectric grease on all connections and replaced the battery and diode board I'm leaning toward the dash light connection. Thanks for all the help.
    I really could be wrong about this, but I have heard that the charging light is part of the charging circuit. If it either burns out, or has bad connections, it affects the charging circuit. Maybe others may know more about this.
    "The difference between death and taxes is that death doesn't change every time congress meets." - Will Rogers

  7. #22
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    Quote Originally Posted by jimmylee View Post
    I really could be wrong about this, but I have heard that the charging light is part of the charging circuit. If it either burns out, or has bad connections, it affects the charging circuit. Maybe others may know more about this.
    +1...the bulb and its circuit needs to operate properly. Snowbum has a section which discusses how to solder in a resistor elsewhere in the circuit to bypass the light...this allows for charging despite a burned out bulb.
    Kurt -- Forum Administrator ---> Resources and Links Thread <---
    '78 R100/7 & '69 R69S & '52 R25/2
    mine-ineye-deatheah-pielayah-jooa-kalayus. oolah-minane-hay-meeriah-kal-oyus-algay-a-thaykin', buddy!

  8. #23
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    Oddball?

    OK, here are two oddball things to check, as we seem to have run thru the normal:

    Jiggle the ignition key up and down, and sideways, right at the point where the light intensity changes. Does this impact anything with that?

    Take the top cover over the starter off, and manipulate the cable which runs thru the timing cover to the starter. Any change with the light? I had an intermittent problem in that cable which was not visible.

    Looking for things affected by vibration.........

  9. #24
    R100GS, '89 Guenther's Avatar
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    The current through the light bulb is only needed when the engine is dead. With ignition on the small current through the light bulb is enough to energize the magnetic coils in the rotor to start generating power in the stator. From that point on the voltage regulator takes over and the light bulb extinguishes because now it is feed with the same charging voltage from either side.

    Here is a diagram of the charging system.

    I like jforgo's suggestion for things to check.

    Especially the wire that comes down from the voltage regulator going to one point of the rotor. Could even be the wire/connector of the other point to ground (at the stator housing). If one of these connections fail the magnetic field in the rotor breaks down and hence no voltage to the diode board and the light would come on. The voltage at the battery would drop to the voltage of the battery (<13V) and a voltmeter would no longer show a charging voltage (>13V).

    I would rig up the voltmeter so I can read the voltage at the battery when the light comes on while riding.

    /Guenther
    Last edited by Guenther; 12-15-2013 at 05:17 AM.

  10. #25
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    Good ideas, I haven't checked the wiring to/from the starter circuit. That and build connections are now on the list!

  11. #26
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    Should be BULB connection, not BUILD....

  12. #27
    Bill Clark
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    What Rick said........

    The red light activity at 3500-4000 is a good indication of a loose or marginal connection somewhere,as this corresponds to the onset of the first vibration zone in most Airhead engines.
    *Double check ALL wiring to the diode board and alternator,especially the red wire that goes from the diode board to the starter solenoid battery cable connection. This wire is the only path for alternator-produced current to return to the battery-when compromised,this wire can keep the battery from getting charged.

    With that being said, I had the same issue. I fought with it over a period of time and ended up changing the three wire harness from the alternator to diode board (PN 12 32 1243178). This solved my problem. The receptacles in the harness were checking okay electrically, I tried crimping them, dielectric grease, etc. all to no avail. Replaced that harness, wow, was it really that simple? Yes. After confirming my problem, the other possible suspect is the red wire Rick mentions, and because of the spade/receptacle configuration, I replaced it too. No electrical gremlins since 2009.
    Bill

  13. #28
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    Thanks Bill. I haven't checked the wiring harnesses and will include this check along with previous connection check suggestions (key switch, charging bulb, starter relay, starter cables).

  14. #29
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    Problem Solved!

    After checking the dash bulb, starter connections and ignition switch, I installed a voltmeter and found max charging at 13.6V so I decided to replace the wiring harness Air Race Addict suggested. One of the plastic covers over the spad connection came appart in my hand, one of the others was taped togethor. While installing the new cable I pulled on the stator housing's three terminal connector block wires and one of them was not soldered correctly. Either vibration or a previous repair cause this wire to be loosely connected to the block. After cleaning up the wire, which had blackened from shorting, and soldering the connection to the block all is well. No charging light even at idle. Now waiting for the a break in the weather to assess charging voltage underway but I believe problem is solved!

    Kudos to all who suggested cleaning, checking connections, looking at areas affected by vibration and Air Race Addicts suggestion to replace the cable.

    Charlie

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