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PMA rectifier 20 volts

Discussion in 'The Garage' started by Jthomas, Aug 1, 2019.

  1. Jthomas

    Jthomas XS650 Enthusiast

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    Battery delete. Kick only. Custom harness rat bike. Pma and pamco.

    Bike left me stranded after 500miles on new PMA and pamco from TC bros. No spark at all.

    After troubleshooting i found the pamco plate to be “bad”

    (I hooked up a spare pamco plate my buddy had) - bike had spark again

    Very shortly after, the bike didn’t run anymore. Still had spark. But it would just pop and kick back hardddddd. Blew my ankle out.
    It acted like the timing was wayyy offff. No matter where you positioned the plate, always the same effect.

    TC bros sends new plate. I install.
    (I unplug the red/green from the regulator/rectifier wire from my cap)
    Hook up a battery instead
    Bike fired up first kick.

    I measured the voltage coming out of the rectifier, and it was pretty well between 15-20v for most of the time at idle.

    I’m pretty sure that just cooked two ignition plates. One of them not even mine.

    My question is, how do I tell if the rectifier is “bad” or if is something in the stator going to the rectifier?

    As in. Did the rectifier just die on its own, or did the stator/charging system kill it?


    Thanks
     
    Last edited: Aug 2, 2019
  2. XSLeo

    XSLeo XS650 Guru Top Contributor

    A lot of te PMA systems out there use a cheap reg/rec to keep cost down. These crap out early .
    The unit you call a rectifier does more than rectify the AC from the stator to DC the bike can use. It also has a voltage regulator in it. The only way to test is to swap in a known good one. It sounds like your went bad.
    There are several types of PMA reg/rec's out there.
    I think a mosfet type is the type being recommended, more costly but a much better unit.
    Someone should come along and tell you more about it. I don't use a PMA. I don't think they are worth all the hype they get.
    Leo
     
    Last edited: Aug 1, 2019
    peanut and gggGary like this.
  3. Jthomas

    Jthomas XS650 Enthusiast

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    When I built this bike, I wanted it simplistic and reliable. I figured what would be more reliable than a magnetic alternator. Shoot, all dirt bikes run no battery and magnetic alt just fine.

    But after more reading, it seems like the products available for us/our bikes are kind of unreliable. It’s a shame.

    Need to figure out if it’s the alt killing the regular or if it’s dying for another reason.
     
    gggGary likes this.
  4. Ratranger

    Ratranger XS650 Junkie Top Contributor

    gggGary likes this.
  5. XSLeo

    XSLeo XS650 Guru Top Contributor

    All alternators are magnetic. A PMA has permanent magnets. Our stock alternator uses an electromagnet.
    If an alternator like used on our XS650's wasn't reliable why do cars vans, trucks, buses, most everything that has an engine and goes down the road use them.
    When was the last time your car alternator quit working? How about anyone you know?
    The only advantage a PMA has is when properly set up they can be ran without a battery. If anyone tells you something different they just want to sell you a PMA system.
    Leo
     
    peanut, gggGary and GLJ like this.
  6. Jthomas

    Jthomas XS650 Enthusiast

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    I used the term “magnetic” referring to permanent magnets. In my lifetime, I’ve changed more alternators on cars and trucks, than I ever have on any dirt bike I’ve owned. In fact, I’ve never changed one or had issues with one on my dirtbikes! *knock on wood*

    That’s why, in my mind, I wanted to go with pma. I wanted the peace of mind that I could always kickstart my bike or push start it, no matter the condition of my battery. Also why I deleted my battery. Never owned a bike that had one, never had a problem until now.
     
    gggGary likes this.
  7. Jthomas

    Jthomas XS650 Enthusiast

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    whats Killing the regulator or rectifier? The alt or are the regs just junking on their own?
     
    gggGary likes this.
  8. 5twins

    5twins XS650 Guru Top Contributor

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    Usually, the reg/rec units are at fault because they're low quality. They are what's called the "shunt" type. They bleed off the excess voltage in the form of heat and, well, they just can't take it for very long before burning up. You'll want the better type of reg/rec that Ratranger mentioned. Even replacement "shunt" type PMA reg/recs aren't that cheap. You may find one for around $30 but chances are, it will burn up quickly too.
     
    gggGary likes this.
  9. Jthomas

    Jthomas XS650 Enthusiast

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    I’ll shop around. I bought the bike to spend money, so a little extra for a nice unit is fine.

    Also, I have incandescent lights on it and a 5v usb charger for my phone. Not sure what’s too much for no battery, alt only.
     
    Last edited: Aug 2, 2019
  10. arcticXS

    arcticXS XS650 Junkie

    "Too much" is when the voltage drops below 13.5 v or so. Until that happens, more load/ consumption is a good thing, giving the regulator an easier life.
     
    peanut likes this.
  11. gggGary

    gggGary Stop that! Top Contributor XS650.com Supporter

    I doubt it's the PMA that's the problem. But an intermittent connection somewhere causing voltage spikes might hasten the Reg's death. As many have said the cheap Chinese regs have been very problematic. I was just looking at these today.
    https://www.banggood.com/Geekcreit-...l?rmmds=home-right-flashDeal&cur_warehouse=CN
    2019-08-02-14-46-www.banggood.com.png
    Thinking if I was to ever install one of my PMAs I'd be sore tempted to feed the "Pamco" through it.
    Then again using cheap Chinese parts to fix a problem with cheap Chinese parts....
    Hint add a cheap Chinese voltmeter where you can see it.
    Your dirt bikes used quality Japanese electronics.
    China will get there one day but maybe not soon.
     
    arcticXS likes this.
  12. xjwmx

    xjwmx XS650 Guru Top Contributor

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    There ought to be a pma from a dirt bike that you could adapt, with proven Japanese quality.
    Think I've read about one or two in the past but was never into pma enough for them to really register.
     
  13. gggGary

    gggGary Stop that! Top Contributor XS650.com Supporter

    The banshee swap was a thing for a long time But Hughes took over with a bolt on bracket for his set up making for an easy install. For the most part the PMA itself is reliable it's the regs that have given probs of late. Note HHB sells an upgrade reg also.
     
    Last edited: Aug 2, 2019
  14. hotdog

    hotdog XS650 Guru

    As mentioned above by Ratranger, Shindengen is the go to for Mofset reg/rect and can easily be found on wrecked Japanese bikes.
    Personally I run a Shindengen FHO20AA and have had no issues. These have been salvaged off of wrecked Honda CB500R's. Both have been in excellent cond and have cost approx $40 AUD each - much cheaper than springing for a new one. And the guarantee that it is a genuine one - not an ebay China knockoff.
    That said, I have ensured all of my wiring is in good order.
    Additionally, DO NOT run LED lighting components and always ride with lights on.

    Older HD's used to do the same thing with their single phase PMA setups and reg/rect's - if run with lights off all the time reg/rect burnout was a common occurrence. In the shop quite often I used to change out 'the trifecta' of a boiled and cooked battery, fried reg/rect and a burnt out PMA.
    I can assure you, nothing smells as good as removing a harleys primary drive, full of sweet burnt electronics aroma all through it......
     
    gggGary likes this.
  15. Jthomas

    Jthomas XS650 Enthusiast

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    I normally ride with headlight off.

    Could I just get really any regulator off any jap dirtbike?

    I’ll do some more research tonight.

    I’m really sure that I have solid grounds. I had the bike down to a frame, and sanded the grounding points to bare steel. Any any connection I had got dielectric grease.
     
  16. 5twins

    5twins XS650 Guru Top Contributor

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    For what the PMA kits cost, they should include the good reg/rec.
     
  17. Ratranger

    Ratranger XS650 Junkie Top Contributor

    You need a 3 phase reg/rec. There are many bikes that use them. But buying a used fh020, or the even better sh775 is really the better way to go. The sh775 runs cool, my bike charges at 14.2V and after a 20 mile ride the reg is still cool. It'll sit at 13-13.5V right after start, but once the battery recovers it goes to 14.2 and stays there. There have been plenty of regs tried, but the sh775 is the "ultimate" upgrade as of now. Even people with newer bikes are swapping to them or similar. They extend stator life, run the stator and reg cooler and are more consistant on power delivery.
     
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  18. hotdog

    hotdog XS650 Guru

    Geez 5T, your not getting the point at all....that would hurt profit margins and the opportunity of selling an additional reg/rect once the original poorer quality unit toasts itself (planned obsolescence much?) LOL ;)
    Additionally, it has been proven many times that its far cheaper to piece your own PMA together buying the parts yourself from either Alixpress/ebay/banggood - where do you think the resellers get them from? At which point you could also source your own quality Mofset reg/rect secondhand for much less than optioning up your new kit with one.
    But I'm getting off topic - back to fixing the OP's issues......
     
  19. 5twins

    5twins XS650 Guru Top Contributor

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    Careful what you say here, you'll get accused of having a $5 brain, lol.
     
  20. xjwmx

    xjwmx XS650 Guru Top Contributor

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    Maybe the thing to do would be use the Banshee reg.
     

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