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Ducati ST2 1998
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Discussion Starter · #1 ·
Guess it’s my turn to get more involved in the wonders of the regulator/rectifier... My ’98 ST2 has stopped charging my 2 year old (lithium) battery. 2 repairs on the stator wires over the last 6 years have prolonged the life of the Shindengen SH673-12 that was mounted on the frame member above the battery. But the white wires have more or less become brittle up to the RR body, which now quit working all together. I’m quite sure this ‘update’ has been installed just a few years into the bikes life, so the Shindengen has done it’s time. Did some multimeter measurements, thanks to the flowchart I found on this forum. Stator measures OK: 2 white wires are open to ground and across them I measure 0,9 Ohms.
Obvious choice would be to go for a mosfet type (FH) instead of the shunt type (SH), preferably a single phase, although according to the various messages on this forum, a 3 phase would also work; it could even provide and extra set of diodes just in case. Mainly capacity should match: since our generator puts out 420 W, I assume a 30 AMP rated RR would be needed (Regulators/Rectifiers | Motorcycle Products | SHINDENGEN ELECTRIC MFG.CO.,LTD).
Original Shindengen RR’s seem to be a bit more complicated to come by. The aftermarket from Electrex could be an interesting alternative, with correct wiring (which I would have to restore) and seems small enough to go on the original location below the headlight (which should provide better cooling). The Electrex website however issues a warning of non-compatibility with lithium batteries. Ducati Sport Touring ST2 Regulator Rectifier - RR50. Other mosfet RR are explicitly allowed in combination with lithium batteries (CARR504 - Ducati ST2 MOSFET Voltage regulator rectifier [CARR504 Ducati ST2 regulator] - €119,00 : Carmo Electronics, The place for parts or electronics for your Motorbike Quad Scooter Car or Jetski). State of the art seems to be the FH020AA from Shindengen, which is also compatible with lead and lithium.
I would also prefer to have the charging light connected again and I’m still in doubt as to whether to replace the stator or it’s wiring.
Any additional input, experience and recommendations from the experts here is appreciated!
Thanks all – take care
Filip - Belgium
 

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I went with the FH020AA from Roadstercycle. They're in the US, but do ship internationally. Their FH020AA will work with the '98 single phase. It's large enough that it won't fit in the nose cone, but it runs so cool that it should be able to be mounted just about anywhere else. Some folks have ground down the fins and cut the wire entry point to get it to fit there, but I didn't want to go that route.

There are a couple threads on stator testing to verify sufficient output that I'll try to locate. But if the wires are brittle, it sounds like it would be a good idea to replace them, so long as the stator is functioning properly.

Hopefully some more folks with single-phase experience will chime in.
 

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I don't have single phase experience, but I did just fit an FH020AA from Roadstercycle as well. I turned it upside and trimmed a spare used nosepiece that I purchased so that I could mount it upside down under the nose. It gets it into the air that way, and makes the wiring easy, and no trimming of the fins required. So far, so good.
 

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I have a single phase stator on my 1997 ST2. I also fitted an FH020AA . It has been working great for about 5 years so far. Previously I had tried a couple of no name ebay type RRs but they only lasted a few days! I went to some trouble to mount it low down behind a vent on the left side of the H cylinder, where the horn is, but with hindsight these things only get warm, not hot like the originals, so placement may not be so critical. It's true you do not get the charge light .....so, at the same time I fitted a cheap digital voltmeter display which lasted a year or so but as there had been no more voltage/charging issues I haven't bothered replacing it.
 

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+4. Ditto all three above responses. I went through a ton of r/r on my '98 until switching to the mosfet. Another note, it is critical to visually inspect the plastic connector to the stator as well as the wires coming from the stator. I found that a bad stator (crusty burnt wires at both ends) was responsible for a few of the r/r I went through, having only done a cursory look at the wires. Black and melting damage inside the connector is not always evident outside - and burnt wires may not always look burnt but the insulation can crumble to pieces in your fingers...
And +1 on the dash volt meter.
 
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Any of the electrical connections/wires should never get hot at all. If they're hot enough to make the insulation crispy, then that's very bad. Wiring is there to transmit the power, not radiate it. My 1998 stator plug looked great the 1st time I peeked in there. Then I started getting the charge light intermittently, and just the inside if the connector was obviously badly overheated. No indication on the outside. Bypassing that connector cured that issue. My 1998 RR never gave me an issue. Maybe I'm one of the few? Or it's the fact that we only get the bad ones posted in here?

My ST4s has 3-phase. The stator connector on this one "yellowed" over time, and I was able to detect heat while it was running/charging. So that connector is now gone, and the wiring runs cool.

And, I had a 2002 V11 Lemans (single phase, 350W) that had 12.5V output to the battery. A 3-phase Ducati RR that I carried as a spare cured that issue. It got the output up to 14 V above idle. That newer Ducati RR always ran cool, so maybe the newer ones have the better mosfets? Although I've seen some ugly pics from Sport Classic era...

FWIW, the ST4s does not have the charging light. I don't miss/need it, since I run an Escort 8500 x50 radar det. which has a voltmeter function (displays voltage when not detecting radar).
 

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Discussion Starter · #7 ·
Thanks all for your replies and input! If the FH020AA would have been available here in Europe (online), i would definitely go that route. But it seems just unobtainable here. Unless i call a Honda or Yamaha workshop, but they are all closed at this moment due to Covid.
Online i only have access to aftermarket from what i think are thrustworthy suppliers. Basically the choices are (all Mosfet): a FH020AA copy dedicated for lithium for 133€ - similar for 118€ which can 'also be used for lithium', or a 1-phase with the right connectors (and control light) for 145€ which 'can also be used with lithium'.
Original connectors are partly useless since the wiring has been changed anyhow, and i also have a digital voltmeter installed on the dash. Tend to go for the first one, German webshop but manufactuerer is RM Stator (which might be US based): Lithium-Ion Batteries Compatible Mosfet Voltage Regulator Rectifier for ATV UTV Motorcycle Snowmobile PWC Scooter.

Thanks
Filip
 

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.... Another note, it is critical to visually inspect the plastic connector to the stator as well as the wires coming from the stator. I found that a bad stator (crusty burnt wires at both ends) was responsible for a few of the r/r I went through, having only done a cursory look at the wires. Black and melting damage inside the connector is not always evident outside - and burnt wires may not always look burnt but the insulation can crumble to pieces in your fingers...
Just wanted to amplify this post. The stock set up seems to have long leads (about 24 inches/600 mm on my '99 Cagiva and similar vintage Monsters/ST's I've seen) from the stator that are connected to the bike's harness via an in-line connector. In my case this connector looked fine from a casual external inspection, but when I pulled it apart there was charring on the contacts and wires with only a few threads on one wire intact. Worth checking, and perhaps eliminating the connector by rewiring direct from the stator to the rectifier.
 

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The Shindengen FH020AA came stock on late model Yamaha R1's if you are having trouble buying it new.

Good luck,
Scott L.
 

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Discussion Starter · #10 ·
Just ordered the RM Stator regulator (see link in my previous post): a FH020AA based, 3 phase Mosfet type, designed to charge lithium batteries. The trick seems to be the charging voltage which in this version is limited to 14,1V, instead of the usual 14,6V or so. BTW, RM Stator seems to be Canadian based, and they have some very informative videos online. Check this one out:
; very nice explanation of what diodes do and how to measure them.
At this point i will leave the stator in, as this obviously is a lot more work to replace and i'm missing the pulling tool. I will surely hard wire the stator wires and leave out any connector (except for the one going in the RR).

Thanks Scott and all members for the feedback. Will keep you posted on how this works out.
Filip
 

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Discussion Starter · #11 ·
Finally found some time to install the new regulator. Slightly adjusted its location, but it still sits on the right hand side above the battery, using a small bracket from the battery box top bolt. The part seems well built and has a sticker 'lithium batteries only'. Just used 2 of the 3 phases. Lost some time on several crimping efforts, and ended up using standard 6,3mm spades that happen to also lock into the connectors. The manufacturer specifies an output of around 14,1V as this presumably would suit lithium batteries better. Upon my testdrive i see 13,8-13,9V with the lights on, max 14,5V at running speed with the lights off. In all i'm quite happy with the result and i hope this combination will continue to work, as will the still original alternator (stator).

Thanks again all for your feedback and comments!
Filip
 

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keep an eye on the spade terminals. they're the ones i see the most issues with, esp in the single phase alt bikes.
 
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