How to fix common regulator/Stator failures

Discussion in '5th Generation 1998-2001' started by Rubo, Jul 7, 2012.

  1. NorcalBoy

    NorcalBoy Member

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    It's hard to fault the results of literally hundreds of folks upgrading the wire gauge and eliminating the connector. MOSFET is the only way to go. It's difficult to argue with verified results, well, at least it should be. :Bolt:
     
  2. NorcalBoy

    NorcalBoy Member

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    This is going to get the party started, ROFL. You think your head hurts now?, just wait. :Pop2:
     
  3. Blackslide

    Blackslide New Member

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    .
     
    Last edited: Nov 27, 2018
  4. Blackslide

    Blackslide New Member

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    I assume you meant that the alternator always puts out 100%, well no. The stator does not generate excess power, the rectifier draws that excess.



    Riding on the storm
     
  5. FJ12rydertoo

    FJ12rydertoo Member

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    Okay, this is where the misunderstanding starts. From what I've read unless you have a switched field type of alternator, which I don't believe the VFR
    does, you output full power at all times, only dependent on the RPM, regardless of usage draw. This is the way I understand it. So the regulator/rectifier is what determines what is used and what is dumped. It has no effective control of the actual output of the alternator since it is a permanent magnet alternator which allows no real control of the stator output.

    So if I understand correctly, your statement is incorrect.
     
  6. OZ VFR

    OZ VFR Member

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    ^ Correct, the stator always puts out 100%.
    The rectifier converts it to 12v and feeds in to the system, what is not being used up by bike either gets put into battery or is dumped.
    The VFR doesn’t have an alternator, it has a stator. Different things.
    And yes SH is a much better design, that’s why they are known as stator savers.
     
    Last edited: Nov 26, 2018
  7. FJ12rydertoo

    FJ12rydertoo Member

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    Actually it has a rotor and a stator. It takes both to create electricity in most cases. And it is called an alternator because it produces alternating current. If it produces direct current it would be a generator, to be pedantic. :)

    But the stator is only part of the electricity producer, the rotor is the other part and is located on the end of the crankshaft. But the stator is usually what fails because of the windings, while the rotor is usually simple magnet, but could be an electromagnet in a Field Controlled alternator.
     
  8. FJ12rydertoo

    FJ12rydertoo Member

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    Just one clarifying question: one guy says the alternator only puts out a percentage depending on demand, the other guy says, and which I believe, that the alternator puts out 100% all the time, regardless of demand.

    Which is correct? I don't want to try and tell someone that the thing operates one way when it actually operates a different way. TIA.
     
  9. Blackslide

    Blackslide New Member

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    I believe you are correct. Been up the car world for all my adulthood, so all mechanical/electronic experience comes from there. So I just read a few forum posts, took them by their face value, with too little research, to actually back it up as fact.. Sorry folks!

    Stator output on our bikes, and most as it seems, is only limited by the physics, so it gives what it can at any given rpm. Above 5-6k it reaches max field saturation and can't provide any more. (So at low revs, you are not getting much, and around 9-10k you actually drain the battery).

    Only thing that differentiates the two types of rectifier/regulators, appears to be in the way excess power is wasted. Shunt types return excess to ground (short), while series types cut the path to ground (open).

    Third way, is to try and control what happens in the alternator, but most bikes have saved an ounce of weight and $$$ in mfg. costs there.

    The old SCR shunt type rectifiers run hot enough to heat food on, these new FET/MOSFET shunt or short circuit, type units keep it on a sane level.

    Sorry for all and to NorcalBoy >
    Series, or open circuit, type rectifiers still use the old SCR method. Not MOSFET as I falsely stated.

    Apparently the claims on lower drain on the stator, arises from the principle, that connecting the stator to the ground creates more load, than having no path to the ground. When the R/R has low load on the output.

    I assume, swapping to any modern rectifier and eliminating/severely upgrading the connector, will pretty surely fix the issue.

    Still not sure wich of the two, SH847 or FHxxx would ultimately be more reliable... Apparently MelloDude has had a series type rectifier, but not sure which model.

    A link to the manufacturer, with short explanations, graph, and basics of the R/R internals:

    https://www.shindengen.com/products/electro/motorcycle/reg/

    Riding on the storm
     
  10. FJ12rydertoo

    FJ12rydertoo Member

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    Wonderful, thanks for getting back and setting me straight. Always appreciated.
     
  11. Blackslide

    Blackslide New Member

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    Thanks for pointing out the clear flaw in my reasoning. And that of many, that the marketing B.S. dept. is more than gladly abusing, and supporting, to sell snake oil.

    Riding on the storm
     
  12. Cycleman1

    Cycleman1 New Member

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    As others have noted, stator in the VFR always puts out its maximum AC voltage from about 3000 rpm & above. Below that the rotor isn't turning fast enough to generate much AC voltage. The regulator/rectifier. Rectifier converts AC to DC. Regulator keeps the DC voltage in the range of 14 Volts ( slightly more/ slightly less ), depending on engine RPM.

    In most cases bike charging systems are rated in Watts. So for example if you charging system is rated for 300 watts, the headlight uses about 100-120 watts ( depending on bulb ) brake lights, signal lights use another 50 watts, running all the engine electrics takes another 100 watts, when you add that up you are left with about 50 watts. So you can see before you add anything like heated grips and extra lights, your charging system is pretty well maxed out. Any excess watts are shorted to ground in the stock system. So if you are running heated grips and riding around the city you will be putting your charging system in a negative balance, nothing will be getting shorted to ground and in some cases there will be a draw down from the battery, which if it goes on long enough will drain the battery.

    The charging system on most motor cycle is not a real heavy duty item. It is not designed to charge a dead or really low battery. In reality it works very much like your battery tender at home. It keeps the battery toped off. If you test your battery and after a 24 hr rest cycle, it tests below 12.6, then replace it. Your electrical system will thank you.

    A lot of the problems with any of the stator, regulator/rectifier componets can be traced back to two things, bad connectors or a bad/low battery. There is also the very small percentage that are going to be manufactor related, but the greatest majority of issues are caused by the above two things.

    So do your self a favour. Always keep an eye on your battery, and when replacing them, don't cheap out, buy a mid priced AGM type of battery. If you look after a battery, keep in on a tender in the winter or non riding season, it will last you for 3-5 yrs, sometimes longer. If you don't look after it plan on replacing the battery every year, even less if it gets so low it happens to freeze.

    It has been my experience that bad or low batteries are the prime culprit in charging failures. They put too much strain on the rest of the system.
     
  13. FJ12rydertoo

    FJ12rydertoo Member

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    After doing some research and thinking as you think, I've come to the conclusion that our thinking is not quite exactly correct. The excess voltage from the alternator isn't necessarily sent straight to ground. It can be sent back to the stator windings, if the R/R is a "shunt" type R/R. This has confused me before I started researching it as I thought it was simple and excess volts went to ground through the R/R. It turns out...not necessarily.There is some thought that running more electrical loads will actually help your stator last longer since the shunt-type R/R doesn't have so much excess voltage to get rid of. That is still being debated but certainly makes sense.

    Why the problem with burned stators is more prevalent with the 6th generation I don't know. But they do seem to suffer more burnt stators than the 5th generations. Although the 5th generations have their own issues with sub-standard R/R's. Perhaps the alternators are stronger and put out more voltage and thus more voltage is shunted back through the stator windings leading to more heat. Dunno.
     
  14. Cycleman1

    Cycleman1 New Member

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    I do know that the stators are different between the 5th & 6th generations as they have differrent part numbers. So Honda changed something.

    The stator just keeps pumping the AC out no matter what, as long as it is working. If there is a short at the output end, ie bad connector, loss of ground on the rectifier/regulator end, then that electricity is going to go somewhere. The three yellow wires go to the rectifier/regulator and from there to ground, batttery etc.

    My view is that it is not really the stator itself, but something at the other end that causes the stator to short out. Some of these issues can be traced back to heat. The regulator/rectifier would be much better off if it was more in the air flow.
     
  15. FJ12rydertoo

    FJ12rydertoo Member

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    The stators don't short out so much as overheat from the amount of voltage shunted back to them from the R/R. Once the shunt R/R is replaced with a series type R/R the problems seems to go away. The series-type R/R cuts way down on the amount of stress on the stator due to the way they handle excess voltage.
     
  16. Cycleman1

    Cycleman1 New Member

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    My two cents on that whole issue, is it is the loss of ground, in some fashion or another that shorts everything out. It always sounds like there are a lot of failures, but their are millions of Japanese, Harleys and so on that use this type of stator with no problems. So something else is clearly at work.

    I'm not knocking the series type R/R, but when one replaces his/her old R/R they usually fix the connection issues that likely caused the original failure.
     
  17. CDA441

    CDA441 New Member

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    Hey guys, on another forum in Dutch I've posted my problems considering my bike doesn't charge "enough" or something is sipping battery I don't know of.
    The battery was empty after 9 days of not riding.

    I checked the stator and measure the following numbers over all 3 yellow wires of the stator:
    - 20.1V AC at 1200rpm
    - 50.2V AC at 4000rpm
    - resistance between wires: 0.01 on scale 2k Ohms
    - resistance between stator and ground: infinite
    - leakage current: 1.81mA

    For charging I have measured 14.7V DC over the whole rev range, full load (lights, heated grips)
    Connectors: not molten (even fuseholder isn't molten)
    R/R looks fine too, nothing is molten there, also charging current stays the same so I find it hard to believe there is something wrong with it.

    Anyone any idea that possibly can fix this issue?
     
  18. Cycleman1

    Cycleman1 New Member

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    First off any tests on charging output have to be done with a fully charged up battery in good condition, ie: after 24 hrs have a resting voltage of around 12.7 Volts or better, indicates battery is good. If you are getting 14.7 V at the battery when the bike is running, that is too high for a stock R/R & battery. Continuing to run it at that charging rate will over charge the battery and shorten its life.. It sounds like your battery may be suspect, if you are getting that high charging rate. Have somebody do a load test on the battery.

    In most cases the sotck R/R with a good battery will show a charge rate in the 14 Volt range, somewhat dependent on rpms.

    The only thing that has a resident draw on the battery on these bikes, is the clock. ( computer may have a very minimal draw to retain its memory, but I've not heard of that ever being an issue.) Normally they will take a month or better to draw down a battery. In some of my bikes with clocks, it takes aobut 2 months to draw the battery down enough that a bike with fuel injection won't start. I don't know the actual current draw down of the battery, but the clock shouldn't have caused your dead battery in 9 days.

    So my first suggestion is to have the battery tested. If that is ok, take the clock fuse out and see if your leakage stops. If not you have got something else going on. Heated grips not completely shut off etc.
     
    CDA441 likes this.
  19. FJ12rydertoo

    FJ12rydertoo Member

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    Some of these bikes may have an immobilizer that has a constant draw on the battery. Not sure if that's the issue here,
    but they are pretty common aftermarket gadgets installed.

    It seems odd that you're seeing 14.7 V over the whole RPM range. It should be lower at lower RPM, and ramp up to max
    around 5,000 RPM, I believe that's the high point.
     
  20. skimad4x4

    skimad4x4 "Official" VFRWorld Greeter

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    CDA - I recall your intro post suggested that the bike came with electrical issues - flat battery, broken heated grips and a replaced RR and stator, and you indicated that you had replaced both the heated grips and the battery.

    On the face of it there is no reason to expect a new battery would drain in a few days, and that rather suggests you have some sort of continuous electrical drain which needs to be located - Basically I would do that by pulling fuses whilst monitoring the voltage. When you see the volts rise you know the last fuse is the circuit which was draining the bike. If that does not identify the culprit see if the volts rise after you disconnect any extra connections from the battery terminals.

    Obviously it is a good idea to start the process with a healthy fully charged battery. So I suggest you remove the battery and recharge it overnight using a proper motorbike charger - unfortunately the charge rate on many car battery chargers can be way too high and overcharging is a good way to damage to a motorcycle battery. Ideally use a modern digital motorbike charging unit which has an LED display allowing you to monitor the charging process which will give you a clear evaluation of the state of the battery, and reduce and eventually stop the charging when the battery is full. Next morning take a note of the battery volts across the terminals before installing it in the bike then see if the volts drop once the battery terminals are connected to the bike loom.

    To be honest I am slightly worried by your mention that you replaced the heated grips and also fitted some sort of aftermarket voltmeter from "AliExpress" which sounds very much like a typical Chinese product. Given the high RR output figures you report it suggests you have a non standard RR or the voltmeter is not very accurate - so it might be worth double checking the battery volts using a multi-meter which are usually a lot more accurate.

    Sadly the design of many Chinese sourced aftermarket motorcycle equipment is fatally flawed as they tend to come pre-wired with hoop connectors which people wrongly assume it is sensible to just wire them direct to the battery terminals - rather than do it properly and ensure they are only connected indirectly via an "ignition on" relay. I guess if a voltmeter is permanently live it probably won't draw much power to run an LED display, however heated grips can draw a lot of power and it is way too easy (especially in winter) to accidentally leave them turned on, and potentially flatten the battery if any automatic power down facility misbehaves. Personally I have never been a fan of direct wired accessories which rely on some sort of "automatic power down" feature as I have encountered a few motorbikes where these "automatic" systems fail miserably and yours may be just the latest.

    Hope that helps - let us know how you get on.


    SkiMad
     
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