F800GS R/R Mosfet replacement....How to...

yeah... we're just piss'n in the wind without instrumentation....


If the bottom of the flywheel low enough to be touching oil when the bike is upright and running,
or is the right sidecase semi-dry?

Here's an idea I may have posted some pages back...
If the oil level is kissing the bottom of the flywheel and you drilled a few holes thru the flywheel with the right "lead" angle and maybe a little chamfering of the hole might they scoop up a little oil and feed it in to cool the hot stator?
(Balance would have to be maintained and you'd want to drill so as to not hit any magnets.)

If I recall correctly...... I thought Joel mentioned that one of the catalysts on the stator burn issue was in fact.....poor oil splash dispersion...... So maybe.... But I'm not the one to touch oil channels etc.....



Erling

The stator is stationary and does not spin.
Therefore trying to dip it in oil will not improve cooling splash.
I have been researching this and a thermal additive in the epoxy is our best option for internal cooling since it cools better than air.

​

BENEFITS OF AN EPOXY-DIPPED STATOR
[FONT=Arial,Arial][FONT=Arial,Arial]
[/FONT][/FONT][FONT=Arial,Arial][FONT=Arial,Arial]Benefits of Epoxy
[/FONT][/FONT][FONT=Arial,Arial][FONT=Arial,Arial]Due to torque and vibration created by the alternating current during operation, brushless motor stator coils are subjected to very high mechanical forces under typical racing conditions. Picture it as a super-fast and very forceful tug-of-war between the coils and the magnets. This constant pulling and pushing of current through the coils causes the coils to move in sync with the drive frequency. This force increases as the load on the motor increases.

[/FONT][/FONT]Thermal Benefits
[FONT=Arial,Arial][FONT=Arial,Arial]Another advantage of an epoxy-dipped stator is that it also displaces air (which is a barrier to cooling) from inside the coil, and replaces it with resin. This is superior because it improves the thermal conductivity of heat from the inside of the windings, to the lamination on the [/FONT][/FONT][FONT=Arial,Arial][FONT=Arial,Arial]outside [/FONT][/FONT][FONT=Arial,Arial][FONT=Arial,Arial]of the windings. And since the laminations are on the outside, they also help to dissipate heat into the ambient air. Epoxy dipping the stator will help it to transfer heat and perform better.
[/FONT][/FONT]<TABLE dir=ltr border=1 cellSpacing=0 cellPadding=7 width=282><TBODY><TR><TD height=10 vAlign=top colSpan=2>[FONT=Arial,Arial][FONT=Arial,Arial]In fact, an epoxy-dipped stator is 7.8 times better in heat conductivity than air. And one dipped in epoxy with thermal additives makes it a whopping 73 times better. See the table below. [/FONT][/FONT]Thermal Conductivity (W/m °C)*
</TD></TR><TR><TD height=9 vAlign=top width="50%">[FONT=Arial,Arial][FONT=Arial,Arial]Air [/FONT][/FONT]
</TD><TD height=9 vAlign=top width="50%">[FONT=Arial,Arial][FONT=Arial,Arial]0.024 [/FONT][/FONT]
</TD></TR><TR><TD height=9 vAlign=top width="50%">[FONT=Arial,Arial][FONT=Arial,Arial]Standard Epoxy [/FONT][/FONT]
</TD><TD height=9 vAlign=top width="50%">[FONT=Arial,Arial][FONT=Arial,Arial]0.188 [/FONT][/FONT]
</TD></TR><TR><TD height=9 vAlign=top width="50%">[FONT=Arial,Arial][FONT=Arial,Arial]Epoxy with Thermal Additive [/FONT][/FONT]
</TD><TD height=9 vAlign=top width="50%">[FONT=Arial,Arial][FONT=Arial,Arial]1.700 [/FONT][/FONT]
</TD></TR></TBODY></TABLE>

I was referring to what Joel mentioned....and I believe it was said that it was a catalyst. Lag of oil splash... But perhaps I remember wrong...... I have some thermal heat epoxy that's good for up to 600 deg. F...... Hmmmmmmm.....


Erling

Hmm, well I thought some more and if the alternator is putting out 400 watts and you are using 250 watts, well then the regulator is absorbing the rest... It has to go somewhere. So the low Rds of a mosfet used to switch like a relay probably doesn't apply, it is the linear range, where the mosfet can dump a lot of load. So I was wrong. If your regulator is cooler it is because it has a larger heat sink and not designed(?) to also dump to the frame - indeed I would be surprised a regulator was designed so that the funs were insufficient but it seems that is what bmw have done.

I am not sure why a mosfet is better than an scr in a voltage regulator.

Sent from my GT-I9100M using Tapatalk 2

No one else seems to know.
Joel thinks it is worth trying the MOSFET shunt RR. So Ebrabaek is testing one.
Lukas M thinks we should try a Compufire series RR. C5! is testing one and so am I.

I know the stator is stationary, but it is inside the "counterbored" flywheel.
By using the flywheel to "pump" a bit of oil from the sump
(not a pressurized passage which might steal it from something that needed it more)
The oil would be in the cavity where the stator is sitting carried round-and-round by the flywheel and would run back out more or less at the rate it was being introduced... with the stator at say 190C and the oil being at a much more modest temp. of say 105C this should provide some cooling effect ... I have no idea how practical the idea is ... just throwing it out there...

That makes sense. I think our issue is related to a lack of oil splash for cooling but someone must figure out a way to safely get more flow thru this area. Apparenty the oil volume is negligible on this end of the motor.

Been riding and have a job interview tomorrow at a place I would very much like to work, so been out of the loop.

There is NO oil splash cooling on the K7X stators other then an accessional drip or bit of mist that hits the stator. Of this I am now certain after a long conversation with someone who's first language is German.

The temperature difference between FET and SCR regulators is not relevant to stator temperature as the SCR is simply less efficient on the shorting side. Though less efficient it still holds the voltage down to the same voltage, and in the oe regulators case, lower voltage then most others and THAT is all the stator sees regarding heating and since the oe regulator shorts the voltage down lower, it sees more heating.

Both types of regulator succeed in the same thing, holding the voltage down to a given level so both place the same load on the stator.

Both use exactly the same diode front end to get DC to the regulation circuit so the stator sees the same output resistance.

What does matter, at least some, is the voltage regulation. Higher voltage equals less current through the stator at a given RPM so the FET R/R i recommended and for that matter most other FET and SCR regulators will run the stator at least a little cooler.

Great info 14TLC, great info from that regulator manufacture. Everything they said is spot on to my understanding of electricity which is a HELL of a lot better then what flies around threads about FET V SCR (not referring to this thread) regulators and from FET sales outlets. If they say noise won't be a problem with their regulators, I would trust that based on the quality and depth of information they released.

The K7X spends precious little time above 6,000 RPM with most riders, their series regulator alone is probably good enough.

As far as other series regulator manufactures go, almost no information and the few I talked to were clearly sourcing the hardware and engineering elsewhere as they knew nothing about their own products or electricity in general and worse yet, thought they did, so I haven't found any other series R/R I can recommend so far.

Indy and others... I truly love the concept of thermal conduction. Running 4 thermocouples on the stator winding and one on the cover, there is precious little thermal connection between the cover and windings. the windings are pretty well thermally connected together, so if you can take that heat and conduct it to the cover, the cover will radiate a lot of the heat away itself. Add a radiator (finned heat sink) to the cover and or thermally connect the cover to the block and I think you could cool the stator a LOT.

Either way, a better R/R is good because it also prolongs battery life, but a note. If BMW designed the voltage drop to the headlights for their weak ass 13.84 voltage regulator, the headlight is going to be a bit brighter and also blow every 6,000 miles lol.

If those with higher voltage regulation start blowing headlight bulbs regularly, welcome to what it is like to own an R1200GS and know that it is easy to fix by inserting resistance to the headlight B+ wire.

Cheers and impressive problem solving all. This kind of collaboration is what forums are at their finest!

Thanks Joel!
Let us know how it goes tomorrow - what do we say here "break a spoke" ?

To heck with the spoke..... Break the whole rim tomorrow amigo.....



Erling

Hey Joel, I thought you worked here Good luck mate. If you need a reference I reckon between us all here we could come up with a few.

Given C5's experience with the Compufire series regulator and Joel's comments that the Croatian company looks as though they know what they are doing, I would be prepared to stick one in and see how it goes.

Anyone got any ideas how we might be able to get some exported, as 14TLC says they only sell internally?

I do have some experience with getting product samples from a company there and just getting them out of the country was problematic to say the least, I would be very wary of trying to put a box of regulators in the Croatian post.

The usual is that you have the products marked "defective, no commercial value" or you find a diplomat that will carry them into another country in his diplomatic baggage for a few clams.

Both are highly illegal so the above is for historical informational purposes only.

BUT, doesn't Croatia have free trade with someone? You can often fly products from free trade country to other free trade con tries and wind up almost anywhere. BMW and others do a lot of that.

If all else fails, perhaps a motorcycle smuggling route where you accidentally skip customs check points? Best to replace the timing chain, freshen up the stator first, and run plenty of Techron, but I should think 100 of the darn things would fit in saddle bags, then onto a clandestine meeting with a sail boat. Once near the USA its easy. Our borders are completely voluntary

Unfortunately I am not mates with anyone who's name is Bond and is licenced to carry firearms across borders.

I'll call our international freight forwarder tomorrow (public holiday for ANZAC day here today) and see what they say.

You are kill'n me .............

Diamonds go in the fake muffler

Regulators welllllllllllllllll not so much...............

By coincidence, overnight an F650 single owner in Serbia/Belgrade sent me a thank you re heated grip repair data I have online

He is looking into the Croatian VR Co & is going to come back to me on how you would purchase from them, he has already determined there is a 10% discount on orders for 10 or more VR's.

Have explained to him about this thread & given him the links to take a look, with a bit of luck perhaps he can assist

It seems very unusual that they would only deal within Croatia, they would be restricting themselves to a tiny tiny market. I bet they have a dealer that will ship outside from there or an importer in another country.

If that is really not possible I could pick one up, I travel there every two weeks for work. Was just in Zagreb on Monday but nobody told me anything about their mythical series regulators!

It can't be that complicated.... They are made all over the world. I will contact the importer I got mine from and see if there is a series R/R in his stock.....

Erling

The one you have is a standard Shindengen shunt unit used in many OEM applications. Not one OEM uses a proper 3 phase series regulator, for whatever reason...

I doubt very much that your supplier will have one.

Could be..... I'l post the results when I hear back.....

Erling