LED headlights
 

Installed LED headlights today and on the instructions of course it says do not get any of the electrical connections wet. however there is a heatsink with a fan that goes on the outside of the rubber weather protector which also and electrical connection. Will this be okay? What do you think? http://img.tapatalk.com/d/13/11/10/6a8e4e4y.jpg

I dispute that this fan (it looks like a fan for computers) is build for outdoor use beside the connection is shurely not waterproof. The engine of this fan will be broken very fast due to dust/water whatsoever.

That's exactly what I didn't want to hear. Yes to me too, it just looks like A set up for an old computer with a basic heat sink and a very basic fan. So what do you suggest as a solution to the rain and dirt?

I don't hold out much hope for the fan lasting long, especially if you live/ride in a damp humid climate, which I believe Kyushu is. I think it would be OK in a car installation (under a bonnet), but on a bike...?

Then again, you might get away without the fan on a bike, because the heatsink is exposed to the air and will naturally dissipate heat better than in an enclosed installation in a car?

I think you're just going to have to try it out and see what happens...

Just out of interest, does the fan blow air onto the heat sink, or does it draw air away from it?

How is the light ?

I've been looking a lot at the different offerings promising 1800 lumen from a LED drawing less than 25W

But the cooling had so far put me off - (and the price)

BTW why do you need a fan for cooling? Isn't LED supposed to produce less heat than other bulbs?

The light emitting part of an LED unit feels cool because LEDs don't produce heat in the form of infrared radiation. It’s the infrared radiation that heats halogen bulbs and their surroundings, making them very hot to the touch.

However, heat is still produced in LEDs, but within the LED's electronics (junction heat) due to the inefficiency of the semiconductor processes that generates the light (same reason computers get hot and need cooling). The efficiency (optical power out/electrical power in) of LED units is roughly 5 - 40% (the best being closer to 40%), meaning that 60 - 95% of the actual input power is lost as heat.

The energy consumed by a typical incandescent bulb produces around 5% visible light. An average LED produces about 15% visible light. The rest is lost as heat in both cases. You just don’t notice it in most smaller LEDs, such as a typical 10W LED spot lamp like the Vision-X/Cree, because it’s only 8.5W of conducted heat. In a 55W incandescent bulb it’s 52W or radiated heat, which you will feel!

With high-power LEDs the semiconductor inefficiency becomes a huge problem, particularly because the heat has to be conducted through the body of LED. Radiated heat produced in a halogen bulb is much easier to dissipate. Without a decent heat sink (and fan) the internal temperature of the LED electronics rise, critically affecting performance. As the junction heat rises the lumen output will decrease and the wavelength of light will change for the worse too.

It’s worth noting that in the promotional material advertising HP LEDs all the figures quoted for lumun output will have been measured at a junction temperature of 25C (room temperature) on a test bench in a laboratory. In real world operation the junction heat will almost always by massively higher than this and the lumen output a lot lower.

Go and have a look at a new LED equipped R1200GS - take a look behind the headlight and see the size of the heat sink they've had to use...

I've had one of the LEDs installed for over a week now and the heat sink gets warm to touch but not hot to touch, so I'm optimistic about them not needing the fan. So I am going to continue running it in the winter without the fan and see how it goes. One thing I am curious about is if I keep the fan connected and the fan eventually fails, do I run the risk of causing a short or any other electrical problem?
As far as brightness is concerned i originally thought I noticed quite a large difference but now I am more inclined to say the difference is quite marginal and the LEDs are only a tad brighter. However my main concern was the electrical power consumption so I'm very happy with that if I am able to continue to run them.

Yes it could fail with a shortcut due to salt, water and dirt - so might be good idea to put a fuse inline with it.

Normally those fans don't short when the break, but in the outside environment i would'nt be to sure ...

Do you think it would be advisable to disconnect the fan?