Charging system diagnosing... Is it really working right.

Discussion in 'Parallel Universe' started by ebrabaek, Jul 18, 2012.

  1. ebrabaek

    ebrabaek Long timer

    Joined:
    Jan 12, 2010
    Oddometer:
    4,886
    Location:
    Grand Valley, Colorado
    I looked in the thread index, and could not find any specific charging system specific test.... But as I am sure I have seen several reply's regarding this.... I decided that with the many wondering electrons lately, I'd write a quite simple system up.

    Pardon me if this is buried somewhere where I could not sniff it out.:d. The following procedures are simple and not derived from any manual, but rather a few years testing the systems on different bikes. So bear with me, as I might mention something that the manual differ's with.

    Starting with a simple explanation of the charging system on the 800GS, which is quite similar as on many other bikes. You have a flywheel that holds a permanent magnet that when spun over a coil (in this case 3 coils) created inductive energy. Each of the three coils have two connections one side of each coil are connected together as a common ( NOT ground) and each of the other connection goes to the R/R ( regulator/Rectifier)

    The inductive voltage being released from the Stator ( 3 coils) are AC. Those 3 phases (legs) goes to the R/R, where they are turned into DC via a fev diodes,,,capacitors for noise and ripple control.... and in the case of my Mosfet r/r....a Chip ( intergrated circuit) The now rectified and regulated to about 13.8-14.5 volt is then fed to the battery, where it supplies " juice" to charge the battery, and to run the system. It does this to the tune of 400 watts. Simple enough...great... then lets move on.

    How on earth do you know if it is working or not?????? Well.... you have to buy a multimeter to find out, as many don't have an idea.... until stranded somewhere. It really is a simple test that in a few short minutes can reveal if your charging system is up to the snuff.

    First ( and this of course can vary from person to person.... But I prefer a quick and dirty check at the battery to determine a base line. So with the key off the battery should be above 12.5 volts. I realice this is low..... and indicate a severely discharged battery....but never the less That's what I go by..... A fully charger battery will yield above 12.85 volts....

    Then with the meter connected start the engine..... It should jump to a minimum of 13.80 volt......wait a few seconds for the battery to stabilize..... If it does not jump to 13.80 volts... Time to dive in further. Shut off the bike and locate the three wires coming from the stator. Easiest way to do this is locate the r/r ( little box on the right side of the engine mounted to the frame with cooling fins on it) follow the three wires going back from the r/r to the stator..... if you can disconnect then great.

    Then disconnected measure each wire's resistance to ground (chassis) It should be infinite....ie no reading. If it is not infinite... The wire that is not infinite...indicates a shorted coil, and the stator needs to be replaced. If those test are good...then proceed to test the resistance between each wire.... It should be between 0.5-2 ohms. If it is more... There is an open circuit in the coil that measured more..... and the stator needs to be replaced.

    If those tests are good... then start the bike..... Then you need to measure the ac voltage coming from the stator........ by inserting the probes into the terminals on the stator plug..... The measured voltage between each wire should be above 50 volt ac.... if not.... the coil which wires does not produce 50 volts ac, is bad, and the stator needs to be replaced. If they all do....then reconnect the R&R after stopping the engine. Start the engine. If you do not see a rise from idle battery voltage as in the beginning......to the 13.80 volt dc.... the the r/r is bad, and needs to be replaced.

    That's it....your done.... This should be the only tests that needs to be done...... That said... the above test is generic....but will yield the results you need in determining whether your charging system is up to the test....

    Good luck.
    #1
  2. ebrabaek

    ebrabaek Long timer

    Joined:
    Jan 12, 2010
    Oddometer:
    4,886
    Location:
    Grand Valley, Colorado
    #2
  3. Bobo1167

    Bobo1167 On a different frequency

    Joined:
    Aug 16, 2006
    Oddometer:
    270
    Location:
    Auburn, WA
    All 3 stator coils show about 1.4 ohm to chassis.

    I'm going shoping for a ztator. Bobo
    #3
  4. ebrabaek

    ebrabaek Long timer

    Joined:
    Jan 12, 2010
    Oddometer:
    4,886
    Location:
    Grand Valley, Colorado
    Yeppers...... Bad stator... Just to make sure .... When you measured the 1.4 ohms..... The stator was disconnected from the r/r????! You see if it was connected to the r/r during measurement, you could pick up a false reading
    Washing the resistance through the r/r rather than the coil. If it was disconnected..... The 1.4 ohm reading indicates that all 3 coils are shorted to the ground, and thus the stator not producing any out put...... As you have experienced. Where are you stranded??????
    #4
  5. def

    def Ginger th wonder dog

    Joined:
    Feb 28, 2004
    Oddometer:
    11,012
    Location:
    The woods and mountains of Alabama
    Are these stators being replaced with another stock stator? These things can be rewound with good results.
    #5
  6. ebrabaek

    ebrabaek Long timer

    Joined:
    Jan 12, 2010
    Oddometer:
    4,886
    Location:
    Grand Valley, Colorado
    So far there have not been great luck with longlegivity after a rewound. As of late, many have gone the stock route, as it supply's the new flywheel, which has the improved cooling holes in it.
    #6
  7. JRWooden

    JRWooden Long timer

    Joined:
    Jul 5, 2008
    Oddometer:
    4,323
    Location:
    The great state of confusion
    I've been saying I was going to call "Custom Rewind" a shop that has a good reputation for stator rewinds, but hav e not done it yet ... I will do so this coming week. As Ebrabaek notes, some rewinds are not holding up well ... In many cases the temperature rating of the insulation of the wire commonly used by rewinders is 160F or 180F ... that is no good for this application (at least with old-style flywheel) as the stator reaches temperatures of 200F.

    I'll report back with results of my call to Custom Rewind.


    #7
  8. BK

    BK Electron herder

    Joined:
    Jan 28, 2011
    Oddometer:
    653
    Location:
    Indiana
    Paragraphs save lives!

    :D

    #8
  9. BcDano

    BcDano One Lucky Dude

    Joined:
    Nov 11, 2010
    Oddometer:
    328
    Location:
    Rolling on the RTW
    I had to replace mine on the road in Mexico city. Got a great replacement from Ricks. Very good product and far better than the OEM which you can't get anyway. http://ricksmotorsportelectrics.com/part/21-023/MDlCTVdGODAwR1M=

    Be sure to also to get an OEM gasket as the old one will be toast. You will also need some high temp sealant. Easy install as long as you take your time.

    Sounds like the stator is toast. Easiest is just to test at the battery. If you fire the bike up and its not producing a solid 14+ volts something is wrong.
    #9
  10. ebrabaek

    ebrabaek Long timer

    Joined:
    Jan 12, 2010
    Oddometer:
    4,886
    Location:
    Grand Valley, Colorado
    Your absolutely right...... Thanks. Not kidding. Looks much better now.:clap
    #10
  11. BK

    BK Electron herder

    Joined:
    Jan 28, 2011
    Oddometer:
    653
    Location:
    Indiana
    You're welcome, I was hoping you would take it in the helpful spirit it was offered.

    Nice write up btw, it's great when knowledgeable people take the time to spread the wisdom. Your write up could save someone a lot of grief, and money too!
    #11
  12. ebrabaek

    ebrabaek Long timer

    Joined:
    Jan 12, 2010
    Oddometer:
    4,886
    Location:
    Grand Valley, Colorado
    Absolutely. :thumb:freaky
    #12
  13. yns

    yns cretan inside

    Joined:
    Dec 21, 2009
    Oddometer:
    61
    Location:
    Crete, Greece
    Great step by step instructions! :clap

    In fact, on my bike they showed 1.5, 1.6 and 1.5... All tree shorted like you mentioned at the other thread. On a friend's bike the multimeter showed O.L. (and I guess this means infinite; correct me if I'm wrong).

    Tomorrow I'll have the stator rewinded by a local company but I think I'll buy one of the 3 options available just in case... And I guess one of the Mosfet R/Rs..
    #13
  14. ebrabaek

    ebrabaek Long timer

    Joined:
    Jan 12, 2010
    Oddometer:
    4,886
    Location:
    Grand Valley, Colorado
    Sounds great. Look up my mosfet replacement thread, if you have not already seen it.....:clap
    #14
  15. yns

    yns cretan inside

    Joined:
    Dec 21, 2009
    Oddometer:
    61
    Location:
    Crete, Greece
    I have, I have... :nod

    In the next 2 months I have to change knobbies, do the 40.000 km service including valves, change chain and sprockets, install a hyperpro -2.5 cm kit, replace stator and R/R... and all these before someone in Europe decides that we all have to work in my country without getting paid...

    In any case your thread clarified all my doubts about the charging system and how to diagnose failures!
    #15
  16. ebrabaek

    ebrabaek Long timer

    Joined:
    Jan 12, 2010
    Oddometer:
    4,886
    Location:
    Grand Valley, Colorado
    I feel your pain. Regardless of why this happened, I can only imagine the pain you must feel. You have a beautiful country. I spend a few weeks in Kreta, back in 1987, and beside of our Sergeant's beard catching on fire while drinking Raki....all went fantastic. Blessings.
    #16
  17. Shawnee Bill

    Shawnee Bill Long timer

    Joined:
    Feb 25, 2006
    Oddometer:
    2,172
    Location:
    Oklahoma
    Ok, '10 F800GS at 30,800 miles my battery died after a 40 mile ride. It was so bad it wouldn't keep running after a jump start.

    So new battery, starts fine, rode about 20 miles and the battery was too low to crank the motor.

    So recharge battery on charger, battery reads 12.8 with engine off, running voltage climbs slowly to 13.8 no matter the RPM.

    Pull the stator off and it looks burnt.

    So to the stator test, with stator unplugged ohms across each coil is .6 ohms, all 3 have infinite resistance to ground.

    Running voltage across any 2 of the 3 wires reads 12.6 volts AC at any RPM, that's with the stator plug connected. Should the stator be unplugged for this test? The way I read it should be connected.

    Everything reads good except the AC output. That means I have a bad stator? The output on the stator wires seems a little strange since I'm reading 13.8 at the battery? And somewhat puzzling that the battery dies while ridding.

    Three year warranty was up in February.

    .
    #17
  18. JRWooden

    JRWooden Long timer

    Joined:
    Jul 5, 2008
    Oddometer:
    4,323
    Location:
    The great state of confusion
    #18
  19. ebrabaek

    ebrabaek Long timer

    Joined:
    Jan 12, 2010
    Oddometer:
    4,886
    Location:
    Grand Valley, Colorado
    I corrected the original post to be less ambiguous. The stator should be disconnected from the R&R when checking ac voltage. If you check it connected the results may not be valid, as the R&R shunting the stator output will lower the ac reading, so as not to be reliable. Unplug the stator from the R&R run the ac test, and post the results. The other tests are good regarding the stator.
    #19
  20. Shawnee Bill

    Shawnee Bill Long timer

    Joined:
    Feb 25, 2006
    Oddometer:
    2,172
    Location:
    Oklahoma
    With stator unplugged, engine running about 3,000 RPM I get 40 volts AC from each winding.

    I'm wondering if it may be breaking down when hot?

    [​IMG]
    #20