how hot can a rectifier/regulator safely get?

[motorbyclist]

long story short, it wasn't in a well ventilated place and got pretty damn hot while riding today. it wasn't hot enough to burn you at a touch, but too hot to hold.

since been moved, but i was wondering how hot it can safely get to?

am i likely to have done some significant damage?

how will i know if it's damaged?

the wiring wasn't hot further down the line, but a few cm near the device had heated up along with the heatsink - will the insulation suffer much?


it's an aftermarket one on my NC30. i replaced my badly bent subframe to find the reason for it's bendiness was that a previous owner has cut the frame to accomodate the reg/rec which is bigger than the honda one. not wanting to have another dodgy frame i simply left it ontop of the battery under the seat. clearly there is no air circulation there. so after an hour or three like that (longest run was 30minutes with a 10min break between errands), it has since been moved to a place that offers cooling.

[Spuds1234]

If your battery is still charging, you probably havnt done much damage at all.

If your really worried about the thing heating up get a cheap 80mm fan and cable tie it to the heatsink.

[vifferman]

Did it have flames coming out? Did it, huh?
If not, then it's probably OK.
Ideally, it should have some airflow AND be affixed to summat metal, with heatsink paste between it and the metal thing.
The first (of 3) R/R mod I did was on my VFR750. The R/R carked it, and the replacement one had been taken to by Spectrum with an angle grinder to fit it under the fairing. I was unimpressed by this bit of Kywy Ungunooity, so I cut the wiring, ripped out all the wiring from the R/R to the stator and battery, and rewired it with heavy-duty wires. The R/R ended up mounted under the headstock where the horn normally lives, on a piece of 4mm thick aluminium, and I doubled up the wires to the battery and earth points, got rid of all plugs, and crimped and soldered all the connections, before heatshrinking them.
Got an extra half volt from the decrease in resistance, and eliminated most of the potential problems.
Blah blah blah.

Then my VTR1000 R/R carked it.
Currently, the one on the VFR800 is OK, but I fitted a PC fan to it to help a mite, and added some heatsink paste between it and the frame, just to help it a mite.

Blah blah blah.

Yeah, I know I'm boring, a dweeboid, etc etc.

[Squiggles]

Run a computer fan to it? go on, you know you want to, just one of those 12V jobs

[scracha]

After spending nearly $400 on a replacement VFR750 reg/rec then I'll third the computer fan option. Wiring it up to the lights (the current draw is minimal) so that there's no danger of you leaving it switched on) is the easiest option or spend a bit of time finding a wre that's only live when the engine is running.

[vifferman]

After spending nearly $400 on a replacement VFR750 reg/rec then I'll third the computer fan option. Wiring it up to the lights (the current draw is minimal) so that there's no danger of you leaving it switched on) is the easiest option or spend a bit of time finding a wre that's only live when the engine is running.

Quite honestly, even though I have one (because it was free!), I have to say that a fan on your R/R does very little, apart from making you feel you're doing something good. Yes, some tests have shown that it does result in a slightly cooler-running R/R, but basically your R/R is either going to be OK or it isn't, and the fan makes no significant difference to that.
The best things you can do to your charging system are these:
1. Eliminate as many connections as you can, replacing plugs with solid joins, and using heavy-gauge wires that are short as possible. If you can't replace plugs, make sure they are in good condition, free from corrosion, tight, and protected with electrical grease to stop further corrosion.
2. Check the earths (grounds): make sure they are tight, and corrosion free. If you can, make sure you have two negative connectors from the R/R: one to the battery, and one to earth. Doubling up the earth points in the wiring loom of your bike is also wise. One to the frame, and another to the engine is good.
3. Make sure your R/R is where it can get lotsa cooling air. The newer bikes (particularly Hondas) have R/Rs hidden underneath bodywork, where they get very little fresh air. A cooling fan is therefore mostly only circulating hot engine air.
4. Fit a voltmeter to your bike, somewhere where you can check it when riding. This helped me diagnose a failing R/R on the VTR1000.

[motorbyclist]

cheers guys

in it's new spot (right next to where it should be) it isn't getting as hot

a PC fan did come to mind, but as someone said i'd just be circulatling hot air.

a good solution would be to have a vent in the fairing, but it's pretty much right behind my leg so less than ideal

[scracha]

Yes, some tests have shown that it does result in a slightly cooler-running R/R, but basically your R/R is either going to be OK or it isn't, and the fan makes no significant difference to that.

The original 1986 VFR750 (wot I had) has the R/R in the most stupid place possible and it gets absolutely bugger all airflow. The fan definatley made it run cooler. The VFR forums all confirm that they don't blow when a fan is fitted properly. The other option of course is to mount it somewhere that gets a decent airflow. The most cleverer option is to buy an aftermarket one that's got a better design and is cheaper.

[motorbyclist]

The most cleverer option is to buy an aftermarket one that's got a better design and is cheaper.

next time i've got the bike in pieces i'll get out the soldering iron and move it somewhere more sensible

[vifferman]

The VFR forums all confirm that they don't blow when a fan is fitted properly.

Frayed knot.
I've been on the VFR forums since Ages Ago, and I can tell you, if it's gonna cark it, then cark it it will. If you poke around, you'll find lots of cases of R/Rs with fans dying.
It doesn't mean a fan won't help at all, especially if it's fitted from new(ish), but it's kinda like always running synthetic oil on an engine that's nearly poked: it might make you feel more betterer, but it's not going to reverse the damage.

The most cleverer option is to buy an aftermarket one that's got a better design and is cheaper.

Guess what?








Give up? Alright - I'll tell you.
None of the OEM R/Rs are actually made by the bike manufacturers. The most common R/R you can buy is made by Shindengen, who are OEM suppliers to Honda and other Jap bike manufacturers, and to Ducati.
But (however!), if you are dumb enough to buy a "Honda" R/R from the Honda shop, they will happily sell you a Shindengen one (as fitted new to Hondas) and charge you maybe up to twice what the same unit would cost if you don't buy it via Honda. Also (as well), if you have a pre-2001ish bike, then you're better off buying a model of R/R other than the one fitted, as before 2001, Honda wouldn't admit the R/Rs they were fitting were poo (too small). It seems like they were spec'd to fit under the body work, rather than for long life. As far back as maybe 20 years ago, Shindengen made bigger, better, beefier R/Rs, but Honda insisted on fitting piddly little unfinned ones, and hiding the ugly little bastids away under the cowlings.
Yet if you go WAAAY back, R/Rs used to be fitted out in the open air, and still are on most crusiers. So you're quite correct - they need to breathe.

[FROSTY:Me]

Makes ya wonder about an aftermarket solution maybee mounting the RR center of the rad front like n the old days --out in the breeze where it needs to be

[more_fasterer]

The most cleverer option is to buy an aftermarket one that's got a better design and is cheaper.

Wot 'e said. I suggest the Shindengen VR4KB8196, it's OEM fitment for a Yammie quad but is well suited to the NC30 as its substantially "bigger, better, beefier" than the OEM unit and pretty damn cheap - I think RRP is $160 (don't quote me on this, I got a hookup).

Eurobike Wholesale distribute them.

[CookMySock]

most of this electronic-type stuff with a heatsink on it can get hot enough to take ur skin off and still work ok. Anything over 100oC I would look sideways at. Ideally, though, properly designed things shouldn't run hot enough to spook people.

DB