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charging system

Discussion in 'Mechanical & Technical' started by Cab, Jul 3, 2012.

  1. So I am trying to figure out what's going on with my bike. It suddenly died a while back, turns out the battery was dead. Charged it, works like a charm, then battery dies again. Battery is maybe 9 months new out of the box, probably not the issue. I charge the battery, test it, checks out fine, so it must be a charging system issue. I do the voltmeter tests on the stator and the rectifier, I don't get any readings that I shouldn't be getting. I do a battery leakage test, and there is something drawing a huge current. I think wire harness short. I go through the entire harness, redo all joints, shrink wrap, tape, the whole nine should be good. re instal, check leakage, checks out fine. I check the running voltage, higher than when off, so I think it's fine. I take a ride to check it out, dies again. battery died. I charge again, check charging voltage at different rpm's and it begins to climb up to about 5-6K, then it drops back down and at around 9K, it is actually lower than when it's not running.
    So, it is still not charging properly and at this point the only thing I can think of is it has to be the stator or rectifier having issues.
    Does anyone know if the rectifier can change the voltage like that? It also seems to be getting quite hot, and makes me wonder if at some point it got too hot and fried the insides.
    I am not an electrical guru, so any input is appreciated. I really hate to drop money for a new part I don't need that is not the problem and turns out to be money wasted, but I can't think of any other trouble shooting options. I did everything in the manual, it says if nothing checks out and still have problems it's likely one of the two, so which one do I replace first, or do I still have other options to try and get this beast running properly?
  2. Heat is the death of stators.
    Yours is dead

  3. Details, actual voltages and tests done. What bike is it?

    Your voltage regulation is being done in the "rectifier" if it is a R/R integral unit.

    If your ac voltages at the stator check ok, the winding resistance checks ok and the insulation resistance between the windings checks ok I would suspect the R/R unit.
  4. A diode, like most solid state devices can short out when overheated. That would put a dead short on the stator and battery, which in time would destroy both. The diode can still test OK when cool. I would change it SOON.
  5. fist off, thank you for the comments thus far.
    As of now I ordered a new rectifier. I don't have the exact measured voltages at the moment, I can check later. What I recall off the top of my head was something like 12.7V in off, 13.2 running and going up to like 13.5 at 5,000 rpm's. as I kept going higher the voltage began to drop.
    I re-ran the entire wire harness. there is nothing that is touching that shouldn't be. once the new unit arrives, probably friday, I will re check all the voltages and can give exact numbers. till then I have the battery charged and unplugged from the bike. But from the comments and how hot that rectifier was getting, I am suspecting it fried itself, since there are no shorts in the unit itself and nowhere I can find in the wires.
    as far as the bike, its a 2000 cbr 600 f4. I can post a picture of the rectifier if anyone wants to see it. I would be highly surprised if it was the stator that was the issue, since it's not that old and only has like 14,00 miles on it.
  6. 1) Ah ha it's a Honda
    2) what voltages do you see at the output of the stator?
    2a) be sure the stator is 100% before you install/blow new R/R.
    2b) a stuffed stator winding insulation *could* provide similar symptoms, see post #2
    3) Do you see the same current draw on the battery when the R/R is unplugged?
    4) do you see any ac voltage at the output of the rectifier?
    5) see point 1 ;-)

    Please report back after you fit new R/R.
  7. I got the new R/R and a much better design than honda's previous. I installed and was ready to fire it up again but thought I would double check the battery leakage. Sure enough, there is still a 12.16 V draw from somewhere. I began unplugging things until I removed my instrument cluster plug in nothing changed. I then proceeded to unplug every single thing on the harness except for the connection to the battery, ground and cluster. It was still drawing the 12.16 V. I unplug it and of course there is no draw.
    So it must be somewhere going to or from the cluster I deduce. Or is it possible that the cluster itself is the issue. I pulled the back panel off and I saw nothing suspicious. I have re checked all the wires and can't seem to find what would be the problem wire.
    So I feel like there is a short, I don't see any obvious signs, and I think the draw caused the R/R to try and make up for this and fried it.
    So help me out guys, what do I check next?
    On a side note, I can get it basically the same draw as when I check from the - battery cable as when I use just some bare metal on the bike. which makes me think it's a grounding issue, but where could the current be coming from into the ground? :scratchea
    Any thoughts/ input will be much appreciated.
  8. RedKat600

    RedKat600 Vintage Screwball Staff Member

    Voltage draw means nothing....your cluster have a clock in it? That's the 12 V draw. Any time you have a draw, you want to measure AMPS. If you have a clock, I'm betting it's 100 mA draw or less, nothing to worry about and certainly won't fry your R/R.
  9. What he said^^^^^^^^^

    Voltage is potential. Amps is electrons moving, doing work. You may have battery potential at many places throughout your wiring harness even with the ignition off.

    what's interesting is the fact that your charging system is not able to keep up with the current draw at mid-to-higher rpm, evidenced by the fact that the voltage you measure (at the batttery?) falls as rpm increases past a certain point. Have you checked the AC output of the generator before it goes to the r/r? With a fully charged battery, the engine will run with the generator disconnected for this test. the maintenance manual will tell you what to look for. also, measure the resistence between the generator "legs" and from each circuit to ground.

    My guess here is that your stator windings have an internal short somewhere that gets worse with heat/load.
  10. I'm sort of in agreement with these guys above. Throw us a frigging bone. 12.16V is meaningless unless you give us the other voltage when the gauge cluster is unplugged! Even then it is only an indicator. To know the current draw you must measure the current.

    If you really have unplugged EVERYTHING a resistance check across where the battery would have been will tell you if you have a short in the harness.

    How exactly are you ruling out the battery as good? A dead battery will often "look" like a charging failure. I would revisit that if there is a minor disparity between open circuit voltage (battery disconnected) and closed circuit voltage (battery connected but everything still off).
  11. This sounds kind of goofy, but it's worked for me in the past.

    I had an issue like this once on my truck. I couldn't be in two places at the same time.
    Like inside the truck and watching a Volt meter near the battery.
    I took a simple test light and hooked between the + side of the battery and the + cable. Let the test light be the connection.
    The light was on because of a small drain. I got in the truck and started checking things. I think it was a switch or something that was bad, never the less. When I found it and got it unplugged, the light went out. Plugged in the switch in the "off" position and light come back on.
    This is not the most technical way of finding things and of course it wont readings just a connect- disconnect type of thing.
    If the test light is on? You have a connection to ground some place.
    It works if you can't see your V meter.

    Don't light me up if you think this is stupid. It is, but it's helpful sometimes.
  12. KevinD

    KevinD Modulator Staff Member

    This is actually a very useful diagnostic tool.

    Easier & quicker than an ammeter.

  13. +1 and has the added benefit of being intuitive. No light=no meaningful current.
  14. About 6 months ago I picked a nice Fluke 78 from C.List.
    It works great but you have to be close and in sight of the readout.

    It was dark the first time I used the Hillbilly back woods test light trick.
    The brighter the light, the more draw you have.

    What is that saying? Necessity is the mother of all invention?
    So is being broke(no cash or busted truck/bike) and not having the cool tools.
    Have to make my own sometimes.:evil4:
  15. thanks, makes sense what you guys are saying. I was just going off what the manual said to do. I will check the stator when I get back in town. as far as the battery, I just bought it like 9 months ago. I just figured it was fine. But it won't hurt to doubble check.
    As far as checking the stater, all I remember reading in the manual is to check resistance. It didn't say anything about measuring voltage while running. but I will see if I can find more info on that and check out that unit as well.
    Also, I will get actual readings of voltages on all tests and post them up. Make sure I'm not missing anything.
    Thanks again for the imput thus far.
  16. Ok, I completely misread the manual, it was amps not volts. Now I feel dumb. Rechecked all wires, everything looks great. Plugged everything in with only .1 mA draw. So then I check resistance and continuity/ ground on stator all checks out. Have a new R/R and installed. I hook everything up and check resting battery V at 12.7. Start the bike and at idle the battery V is 14.4 and when I rev to 4-5k rpm's it falls to 13.6ish. If I read the manual correctly it is still above resting V and under 15. So it would seem the system is ok, but to have it drop like that seems odd. Is that normal? I didn't get a chance to check the ACV at the stator but everything else seems to check out. I haven't had a chance to check the battery yet but that is on my lst for this afternoon. I only ran it for like 3-5 min and checked battery when I shut it off and read at 11.9, which makes me think it needs help or it was just from the draw from cranking it over a few times to fire it up. So what do you think? Is that normal? Why would the idle be higher than at faster rpm's?
  17. RedKat600

    RedKat600 Vintage Screwball Staff Member

    Something still isn't right....charging voltage goes UP with RPM's, not up then down. I have a feeling your stator is toastified. OR you have a bad wire/connector in the charging circuit. Both are possible.
  18. ^ good stuff right there.

    OP, Were the stator resistances exactly equal when you checked out the stator? (FYI insulation resistance between the coils is more informative if you can find someone to test it for you) What resistance values did you get and were did you take the measurements from? How do the connects look?

    There is a third option. Diminished battery capacity. Ie it looks charged from the voltages but when in service the voltage drops off quickly because it does not contain much charge. It kinda steals the charging current that is also needed to run the bike and drags down the voltage but doesn't really charge much. Test the charge voltage at the battery again at say 3k but let if run for longer. Does the voltage slowly climb or continue to drop?

    With that said it is sooooooo much easier to test, accurately, a charging system by measuring current. Right now you have very little way of knowing if the stator is producing current or not.

    If ya really don't want to spend any unnecessary money or cause yourself head ache always always rule out the battery as an issue first!

    Will the battery re-start the bike without having to put it back on the charger? How many times?
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