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Discussion Starter #1
Give it a couple years and I predict we'll be seeing LED lights with equivalent lumens to PIAA's, etc. In fact, PIAA has an LED unit, but I can't tell from the web site how much light it puts out. Anyone have any experience with their Turbo-L lamp?

http://piaa.com/LEDs/LEDs.html

This company has "LED Light Engines" - this one is 26 Watts at 5500K.
Seems like you could use about 3 of these for a headlight:

http://www.laminaceramics.com/docs/BL_3_White_55.pdf

Product list: http://www.laminaceramics.com/products/
 

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The only problem currently with the LED lights above 5W is that you can't focus, since they are all using multiple LED's(Besides the outragous price)
 

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I have been following LED developments pretty closely for some time now. Got really interested in LED flashlights, and have a few 1 Watt ones, waiting for some 6.5 Watt Luxeon K2 upgrades for my several Maglite 3 cell lights. Luxeon is way behind their release dates for the modules.

There is one problem with them that will have to be addressed for headlights though, and that is the very narrow wavelength band of the light. I am following LED flashlight developments on a website started by flashlight hobbyists (you won't believe what some of these people have tied up moneywise in these lights!!). I was amazed at how fanatical some of these people are, rivaling our LT enthusiasm. :D The issue with the narrow wavelength is outside use, as depth perception is lousy. Incandescant lights put out light in a pretty wide range, and colors and depth perception are good, but narrow band wavelength emitted by current LEDS in the white range cause a lot of washout in colors, and drastically reduced depth perception, causing a scene to look "flattened". LED flashlights are great for indoors and task lights, but not so good for outdoors use.

It is just a matter of time though, as white LEDs are still in their infancy. The LEDs themselves put out very blue or UV light, which is turned into yellow by exciting a phosphor coating on the surface of it. I imagine the development of these coatings is where the advances will be, hopefully getting them to emit a wider color range. If you look at the LEDs in current white flashlights, it looks yellow. That is the coating.
 

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andy said:
you mind sharing this site's address?
It is www.candlepowerforums.com

It is also a Vbulletin powered forum. While you are there, look at the huge variety of emoticons they have available! Makes our little choice box seem inadequate. I tried linking a couple in a post here, showed up in the preview box, but not in the post. :(
 

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Discussion Starter #6
dshealey said:
I have been following LED developments pretty closely for some time now....

There is one problem with them that will have to be addressed for headlights though, and that is the very narrow wavelength band of the light. I am following LED flashlight developments on a website started by flashlight hobbyists (you won't believe what some of these people have tied up moneywise in these lights!!). I was amazed at how fanatical some of these people are, rivaling our LT enthusiasm. :D The issue with the narrow wavelength is outside use, as depth perception is lousy. Incandescant lights put out light in a pretty wide range, and colors and depth perception are good, but narrow band wavelength emitted by current LEDS in the white range cause a lot of washout in colors, and drastically reduced depth perception, causing a scene to look "flattened". LED flashlights are great for indoors and task lights, but not so good for outdoors use.

It is just a matter of time though, as white LEDs are still in their infancy. The LEDs themselves put out very blue or UV light, which is turned into yellow by exciting a phosphor coating on the surface of it. I imagine the development of these coatings is where the advances will be, hopefully getting them to emit a wider color range. If you look at the LEDs in current white flashlights, it looks yellow. That is the coating.

I understand there are two or three methods of making WHITE - phosphor is one of the contenders. Another is a tri-color mix. I think there is a third technique as well. Seems like phosphor wouldn't be any more spectrally limited than a fluorescent light or a gas-discharge HID.

As far as focusing or shaping the light, that would be the job of a secondary reflector mirror, just like we have now. An array of LED's can also be used this way.

I have a 10-LED flashlight (D-Cell) my daughter gave me - it's bluish in tinge, not yellow.

I have no doubts the technology will advance to a point where LEDs will work in headlight applications. As for brake and signal lights, they rock!
 

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davemoore said:
-----------------I have a 10-LED flashlight (D-Cell) my daughter gave me - it's bluish in tinge, not yellow.------------
My LED lights are also bluish, not really as white as I would like them.

What I meant when I said look at the LED, was just that, but not when it is on! That will pretty much blind you temporarily. Even my 1 watt ones are BRIGHT! What I meant was just look into them and see the yellow coating on the LED emitter itself. That is the phosphor coating, and that is yellow. The light is bluish, and most current "white" leds produce 5500-7000K, similar to HID lights in that range, too blue for me.

They are producing some "warm white" led emitters now, so I assume that when the headlights do become feasable the color temps will be wider range emission than current white LEDs.
 
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