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Thread: Intermittent rectifier / charging issue

  1. #1
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    Intermittent rectifier / charging issue

    2009 XB12R

    Battery was bought in Septemeber 2020, bike has regular use and I'm in Hong Kong so never gets cold.

    I keep getting the "Low battery error" so I did the voltmeter mod. Checked the voltmeter against my multimeter for accuracy and it's all good.

    When riding the bike is between 12 - 13.6V, kinda expected higher when on the highway.

    Last week the voltage dropped down to 10v steadily as I was on the highway when I was going slower the voltage was back up to 13. That afternoon I had to jump-start the bike as the battery didn't have enough juice. Yesterday the voltage was fine on the way to work but the bike needed jump-starting again. Started fine this morning. Seems the problem only occurs on the highway with the voltage dropping.


    A month ago I was using the ECM droid and forgot to turn the ignition off for a few hours and fully drained the battery, have I screwed it you think?

    Other stuff I've checked:
    Cleaned the earths
    Tested the stator (60v at 3000rpm)
    Tested the rectifier, it seemed like one of the resistance figures was incorrect. I can't remember exactly but from one pin to ground it was 1ohm and the other was meant to be 3 bit was something like 6.

    Do you think its the rectifier or something else?

    Sorry for the lengthy post. Any input greatly appreciated.

    Thanks

  2. #2
    Senior Member 34nineteen's Avatar
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    Quote Originally Posted by Owenator View Post
    2009 XB12R

    Battery was bought in Septemeber 2020, bike has regular use and I'm in Hong Kong so never gets cold.

    I keep getting the "Low battery error" so I did the voltmeter mod. Checked the voltmeter against my multimeter for accuracy and it's all good.

    When riding the bike is between 12 - 13.6V, kinda expected higher when on the highway.

    Last week the voltage dropped down to 10v steadily as I was on the highway when I was going slower the voltage was back up to 13. That afternoon I had to jump-start the bike as the battery didn't have enough juice. Yesterday the voltage was fine on the way to work but the bike needed jump-starting again. Started fine this morning. Seems the problem only occurs on the highway with the voltage dropping.


    A month ago I was using the ECM droid and forgot to turn the ignition off for a few hours and fully drained the battery, have I screwed it you think?

    Other stuff I've checked:
    Cleaned the earths
    Tested the stator (60v at 3000rpm)
    Tested the rectifier, it seemed like one of the resistance figures was incorrect. I can't remember exactly but from one pin to ground it was 1ohm and the other was meant to be 3 bit was something like 6.

    Do you think its the rectifier or something else?

    Sorry for the lengthy post. Any input greatly appreciated.

    Thanks
    Have you checked the plugs under the belt cover? There could be corrosion or a burnt/melted plug/connection.
    You may want to pick up some freeze spray (or use computer duster spray upside down) to cool down the rectifier to see if the voltage comes back up. It sounds like it may be a heat related issue.
    I know the battery is new, and *should* be good, but it may be worth getting it load tested, just to rule it out. Batteries can do wacky things sometimes.

    Great diagnosis and troubleshooting so far. You've nailed the things I would check first.

    When you said you checked/cleaned the grounds, did you also check/clean where the subframe mounts to the fuel tank/frame? I usually remove the top bolts, loosen the lower bolts and let it hang. This should give you enough room to get in there with some sandpaper/wire brush/dremel (my favorite).

    Also, does battery voltage on the voltmeter match what ECMDroid indicates?

  3. #3
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    Quote Originally Posted by 34nineteen View Post
    Have you checked the plugs under the belt cover? There could be corrosion or a burnt/melted plug/connection.
    You may want to pick up some freeze spray (or use computer duster spray upside down) to cool down the rectifier to see if the voltage comes back up. It sounds like it may be a heat related issue.
    I know the battery is new, and *should* be good, but it may be worth getting it load tested, just to rule it out. Batteries can do wacky things sometimes.

    Great diagnosis and troubleshooting so far. You've nailed the things I would check first.

    When you said you checked/cleaned the grounds, did you also check/clean where the subframe mounts to the fuel tank/frame? I usually remove the top bolts, loosen the lower bolts and let it hang. This should give you enough room to get in there with some sandpaper/wire brush/dremel (my favorite).

    Also, does battery voltage on the voltmeter match what ECMDroid indicates?
    Thanks for these tips. Have checked the plugs (No.77 I think its called and they're fine). Will check the mount between frame and subframe next time I'm messing about with it!
    Also, thanks for the tip with the rectifier, will try some cooling spray on it to see if that makes any difference, and the ECMdroid voltage check too.

    Cheeeeeerrrrsss

  4. #4
    Senior Member Cooter's Avatar
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    Sadly intermittent charging with good wiring usually means a VR on its way out. Rare, but it does happen on these paint shakers. If you can't find and OE one, there are MOSFET, non shunt style upgrades that keep the stator cooler, or try Ricks for a plug n' play but definitely stay away from China on this one.

    https://ricksmotorsportelectrics.com...market-stators

  5. #5
    Senior Member Barrett's Avatar
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    Sir: "voltmeter mod" you speak of? i'm assuming you installed one to monitor charging system performance.
    your answers as follows:

    1-if your battery is a typical "wet-design" and you completely drained it to near 0 volts, then the chances are outstanding that it will never quite be the same again. prepare accordingly.
    2-your 2009 stock VR connects to the main wiring harness behind the stock left front air cooling scoop.....not behind the plastic front belt pulley cover. your VR twin wiring looms are staggered.....the earlier model VR looms are identical in length.
    3-see and read link below. my former board name 'user_deleted". i have supplied all the trouble-shooting steps you'll need to determine a faulty VR including new OEM part number for 2008-2010 XB VR.
    4-Rick's electrics and Mosfet make competitively priced plug-and-play replacements though the stock unit, if treated sensibly, is robust and long-lived.
    5-there are Ebay alternatives but be careful: most are identified incorrectly and you get what you pay for with this Chinese garbage they're peddling. many listed incorrectly. the 2003-2007 inclusive VR has identical length twin plugs....the 2008-2010 has staggered length twin plugs.
    6-prepare to purchase a new VR. yours is finished.

    https://www.buellxb.com/forum/showth...r-Stator/page5

  6. #6
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    Quote Originally Posted by Barrett View Post
    Sir: "voltmeter mod" you speak of? i'm assuming you installed one to monitor charging system performance.
    your answers as follows:

    1-if your battery is a typical "wet-design" and you completely drained it to near 0 volts, then the chances are outstanding that it will never quite be the same again. prepare accordingly.
    2-your 2009 stock VR connects to the main wiring harness behind the stock left front air cooling scoop.....not behind the plastic front belt pulley cover. your VR twin wiring looms are staggered.....the earlier model VR looms are identical in length.
    3-see and read link below. my former board name 'user_deleted". i have supplied all the trouble-shooting steps you'll need to determine a faulty VR including new OEM part number for 2008-2010 XB VR.
    4-Rick's electrics and Mosfet make competitively priced plug-and-play replacements though the stock unit, if treated sensibly, is robust and long-lived.
    5-there are Ebay alternatives but be careful: most are identified incorrectly and you get what you pay for with this Chinese garbage they're peddling. many listed incorrectly. the 2003-2007 inclusive VR has identical length twin plugs....the 2008-2010 has staggered length twin plugs.
    6-prepare to purchase a new VR. yours is finished.

    https://www.buellxb.com/forum/showth...r-Stator/page5
    Thanks for all the info. Kind of thought the VR waa at fault and just wanted a few others to agree before buying a new one. Kinda happy to replace it as it's easier than the stator!

  7. #7
    Senior Member Cooter's Avatar
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    Without actually diagnosing it, we're all guessing.
    But it's a good guess



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