1. Hello Guest. You have limited privileges and you can't "SEARCH" the forums. Please "Log In" or "Sign Up" for additional functionality. Click HERE to proceed.

Charging issues 81 xj550

Discussion in 'XJ Technical Chat' started by Triharder, Aug 31, 2021.

  1. Triharder

    Triharder New Member

    Messages:
    12
    Likes Received:
    1
    Trophy Points:
    3
    Location:
    Maine
    New to me 81 xj550. 11k miles looks like its never seen rain.

    Runs great, all lights etc work, tach cable broken.
    running battery reads 12.8 to 13.5 max at higherr than 3k rpm

    Cleaned w/1000 grit and ox-guarded the following
    Ground from battery to frame
    Male spades on stator and coil
    Also coils and grounds for god measure

    Donor battery 13.3 volts litium from cbr for testing.


    Brushes at 11mm exposed well past wear bar (look new)
    Stator rings dirty to start but now clean.
    Tested at 5.5 ohms

    Magnetic pull test failed at switch on at cover and slightly better at 2k but still faint.

    White resistance from stator at .8 .8 .8 which is high out of spec should be .4 to .6

    Red to green resistance at 6.5 ohm (not part of troubleshooting)

    Swirch on
    Green to ground is 1 v off
    Brown to ground is 12.5
    Running
    Green .75 volts
    Brown 12.2

    Running ac at whites is
    10.3 idle all three
    Running 2 at 13.5 at 3k rpm one set at 10.5 at 3k rpm

    Reg rec passed diode test

    Red at reg/rec plug is 12.6 to battery ground
    0 black to ground.


    Sorry for the long winded first post. I.m trying to fix whats broke and pass the bike forward so trying to avoid shotgun approach.

    Note fuse box looks brand new wires ar each side are 12.5 switch on. I know its suspect but looks usable for troubleshooting.

    I also jumped the green to ground directly to see if magnet got stronger or voltage at battery increased it did not.

    Wire at switch is 12.5.

    Not sure if i suspect wire or stator? Rotor ring checked sat.
     
  2. Triharder

    Triharder New Member

    Messages:
    12
    Likes Received:
    1
    Trophy Points:
    3
    Location:
    Maine
    Sorry for the duplicate post.

    If possible moderators please delete the duplicate.

    thanks
     
  3. XJ550H

    XJ550H Well-Known Member Premium Member

    Messages:
    13,199
    Likes Received:
    3,854
    Trophy Points:
    113
    Location:
    Great North Woods
    issue may be the lithium battery as far as charging voltage.
     
  4. Triharder

    Triharder New Member

    Messages:
    12
    Likes Received:
    1
    Trophy Points:
    3
    Location:
    Maine
    I will buy a lead acid to continue my checking.
    I was hoping to get the charging sorted so i could justify the cost of the battery.
     
  5. Triharder

    Triharder New Member

    Messages:
    12
    Likes Received:
    1
    Trophy Points:
    3
    Location:
    Maine
    I have within an hour away https://ricksmotorsportelectrics.com. Next state over in NH. I was going to bring him the stator and reg/rec to have him test, brushes with cover and hopefully rotor?

    However, I checked the stator wires to each other and they all beeping for conductivity between each pair. Is this a problem? They also beeped for conductivity to ground when installed?

    does this mean my stator is bad?

    (And i did some more research and I will get a lead acid battery on tender at all times to troubleshoot once i get the parts checked).
     
  6. Rooster53

    Rooster53 Well-Known Member Premium Member

    Messages:
    1,852
    Likes Received:
    723
    Trophy Points:
    113
    Location:
    North, FL
    No, I would only call the stator bad if it had continuity to ground when measuring at the 3 terminal connector with it disconnected from the main harness. Or, per the manual it has an obvious high resistance failure between the terminals.

    I wouldn't do anything until you check the charging voltage with the proper battery that is fully charged.
     
  7. Triharder

    Triharder New Member

    Messages:
    12
    Likes Received:
    1
    Trophy Points:
    3
    Location:
    Maine
    I'm sorry to "beat a dead horse". With the stator connected on the bike I probed the connection at the regulator/rectifier and when i touch the white wire and the battery ground it beeps for continuity. All three white wires do this so i assumed it was normal. However, I'm starting to believe its not normal.

    I did not check them with the harness disconnected. And unfortunately i have it apart now? But its easy enough to put it back together and check?

    Thanks for the patience. I was told the bike would not charge when i was gifted it. However, I don't know what they were trying for a battery (new, used, etc?)

    I guess that's my first step to get a new battery (lead acid) and report back.

    Further the regulator/rectifier is not OEM as it does not bolt to the side cover (the bolt holes do not line up).

    i had .8 ohms of resistance between each white to white, so that's high but not grossly high? (might be in leads of the OHM Meter?)
     
    Last edited: Sep 1, 2021
  8. Rooster53

    Rooster53 Well-Known Member Premium Member

    Messages:
    1,852
    Likes Received:
    723
    Trophy Points:
    113
    Location:
    North, FL
    As far as DC resistance goes the 3 wires are effectively shorted because of their "Y" configuration and low resistance, so any resistance reading from one leg is going to look pretty much the same from the other two.

    What meter are you using? Does it have a separate continuity mode when using the audible beep or is it combined with the diode mode? If combined with the diode mode then you are likely reading through the Rect/Reg diodes, and if the probes are reversed you might read through the diode block / headlight relay coil depending on the output voltage of the meter in the diode mode - they vary quite a bit.

    As for charging voltage I am not that familiar with the Lithium, but I believe whether Lithium or Lead Acid a full charge is required to evaluate the charging system. The reason behind this is the battery (either type) presents a load to the charging system, which has a maximum output. With a discharged battery the battery voltage plus charge current will not reach the specified 14.5 +/- .3V.

    So this test is a bit ambiguous but still value added. The magnetic field should be strongest with the engine off and should actually get weaker as the engine is revved (assuming fully charged battery) because the AC output is dependent both upon field coil excitation strength and rotational speed, which would mean a fully charged battery would be overcharged if the Regulator did not reduce field coil excitation as RPM increased.

    That is suspicious, they really should be pretty close to equal.

    I think I would take advantage of that if it is close by and convenient. If he can test the parts under load that would give you some real confidence regarding their condition.
     
  9. Triharder

    Triharder New Member

    Messages:
    12
    Likes Received:
    1
    Trophy Points:
    3
    Location:
    Maine
    Diode function type with .3 ohm restistance betwen leads.

    I jumped the brown, red to battery to see if that would get me better succes.

    It did not. Still 12.8 at tetminals using lead acid fully charged battery

    Also had 12.8 at terminal with key off Then 12.6is with key on so battery checked sat.

    Currently i.m awaiting shop to tell me if they need the rotor for testing before bringing parts in.
     

    Attached Files:

  10. Rooster53

    Rooster53 Well-Known Member Premium Member

    Messages:
    1,852
    Likes Received:
    723
    Trophy Points:
    113
    Location:
    North, FL
    Depending on how the testing goes here is another option. The photo is a 750 Seca, but all you need to find is the two terminal Brn and Grn connector that goes to the field coil and you can duplicate this test. If you do this test it will:

    1. Verify the brushes are making good contact with the field coil slip rings and verify the resistance of the field coil as noted by the current reading
    2. Check the ability of the Regulator side of the Rect/Reg assembly to sink the proper current based on voltage input pin

    [​IMG]

    To check the stator after verifying the rotor has excitation current you can use the below as nominal numbers.

    Disconnect only the 3 terminal connector with the 3 white wires and measure the AC output

    Note that the charging system is running open loop in this mode with the AC generator output disconnected - no increasing voltage to the IC regulator so no feedback. That means maximum AC voltage will be outputted as the IC regulator supplies maximum current to the field coil trying to increase the output.

    Idle of about 1100 RPM = 18.5 VAC
    Rev to about 2100 RPM = 30.5 VAC

    This is measuring phase to phase, and should be equal between any of the 3 wires.

    If you are getting the correct output from the stator then all that is left is for the Rect/Reg portion to rectify that voltage and apply it to the battery.
     
  11. Triharder

    Triharder New Member

    Messages:
    12
    Likes Received:
    1
    Trophy Points:
    3
    Location:
    Maine
    Thanks for posting, i delivered the parts to the local shop for in house testing.

    I.m hoping/fearing the say everything us good? I.ll install new brushes and try again when the finish testing them (hopefully tomorrow but mor likely next week).

    Or hopefully its the reg/rec which would make me feel better knowing the rest passed all my tests.

    That was a good suggestion with the disconnecting feedback wire. I did a similar 'ac' test at the white wires to check output.


    Everything is just a bit out of spec? I.m wondering the year brushes

    Note: bike has 22k miles not 12 so she's at least been ridden.
     
  12. tabaka45

    tabaka45 Well-Known Member

    Messages:
    2,348
    Likes Received:
    494
    Trophy Points:
    83
    Location:
    Brunswick, Georgia
    My brushes were not worn, but they were contaminated with oil from a leaking seal. Fixed the seal and replaced the brushes and that fixed my problem.
     
  13. Triharder

    Triharder New Member

    Messages:
    12
    Likes Received:
    1
    Trophy Points:
    3
    Location:
    Maine
    Shop reported grounded out stator.
    182 bucks and 3-4 time to rewind.

    A few odds and ends to clean upand this project is on hold.

    Thanks again for everybodies help
     
    Rooster53 likes this.

Share This Page