MOSFET reg/rec issues

[Ishrub]

Yes, I have been looking at the possibilities in there...

I had a very similar problem as you did with two replacement Chinese R/Rs in my Roadster (but thankfully was only stranded a few miles from home). After gratefully receiving similar advice from @DEcosse I fitted my SH847 AA a couple of days ago.
As advised it was much bigger than stock and no way I could use the same position or mounts. In the end I wrapped and fixed some felt backed rubber around the rear frame tube and zip tied it in place behind the side cover with the much taller fins faced in where they will hopefully get some air coming past the prop shaft drive.

Will this suffice or do I risk cooking the other electrics? Where did others mount theirs?

Happy to say that voltage measured at my accessory plug is a happy 14.3 volts with the engine running and headlights on etc. Voltage with engine and light off 13 volts.

The rat's nest of wire in my air-box is the excess of an accessory two light wiring loom I should probably cut out.

 

[jtanc39]

I should really keep my mouth shut here (with me knowing nothing about it). Unfortunately, curiosity got the better of me... Wouldn't it be better for the fins to be facing outside to get better cooling rather than facing inwards?

 

[jtanc39]

More importantly I'm curious because I've just gotten the same r/r and looking around to see where's the best location to fix it too.

 

[Ishrub]

I should really keep my mouth shut here (with me knowing nothing about it). Unfortunately, curiosity got the better of me... Wouldn't it be better for the fins to be facing outside to get better cooling rather than facing inwards?

Remember it has a solid metal enclosed side cover over the top and any air can only come from below around the prop shaft. I may need to make an extension and place it under the headlights depending on feedback from the electrical gurus. Other option would be turn it around as you suggest and louvre or gill the side cover to let air in / heat out.

 

[jtanc39]

Remember it has a solid metal enclosed side cover over the top and any air can only come from below around the prop shaft. I may need to make an extension and place it under the headlights depending on feedback from the electrical gurus. Other option would be turn it around as you suggest and louvre or gill the side cover to let air in / heat out.

Thanks for taking the time to explain!

 

[Ishrub]

Thanks for taking the time to explain!

Just saw that @Joesmoe mounted his in a similar way on his Touring but did put his fins outwards as you suggested. The Touring side-covers are different to the Roadster ones but maybe his and your thinking is better than mine . Now I'll read the rest of that great thread that @Joesmoe has helpfully linked in his signature block. Bad Voltage Regulator ...OR?

Please note, anyone wanting to do this must be willing to remove the evaporative capture canister.

As installed:

20160717-d

• Joesmoe
• Jul 17, 2016

Left side cover off showing the SH847 rectifier/regulator. The evaporative canister was removed...

 

[Joesmoe]

I make NO claim mine is the better. I'm frankly banking on this having been designed for the dead winter of Pt Barrow, Alaska, and the high summer of the Dead Sea valley, and taking whatever heat it makes, plus whatever it sees following the engine.

 

[Ishrub]

Maybe I should remove the pad wrapped around the frame downtube and let the R/R touch the downtube to act as a further heat sink?
My idea of the pad was to stop possible rattles vibration affecting the R/R over time or on rough / dirt roads.

Any opinions / comments welcome!

 

[jtanc39]

Wow!!! How fortunate of me. Got a cousin working at a local spares supplier and managed to get the r/r (made in Japan) for approx USD125. I'm from Singapore though.

 

[Joesmoe]

Well, you're a data man (I like that -- data-driven decisions), and I would say you would eschew opinions.

Next step, if so motivated, is perhaps for us to rig thermocouples around there, and go riding.

I suppose we could ride a bit, then arrange to stop right in front of someone with a thermal imager - such as what was used to show the signature of the OEM R/R at the beginning of the thread.