My best LED Light Yet

So I have been thinking about building a new LED light for a while.  I did some night riding last year and found that my homebrew lights were brighter than what everyone else was packing but also were way heavier and messier.  I wanted to build a different light with a lower profile that would be easier to mount and weigh less.  I noticed that www.ledsupply.com had a new LED emitter the Cree XPG R5 producing 315 Lumens of light at 3 Watts.  To understand just how much light that is for such a small amount of electricity consider a  60 Watt bulb produces about 1000 lumens, about 17 lumens per Watt, while this emitter produces 105 lumens per Watt. 

I’m actually powering the light at 1 Amp which its data sheet says should produce 250% of its rated output at 350 mA so its going to produce around 800 lumens. That’s really bright.  I’ve used the light on two walks at night now and its like having a car headlight on your head. 

Ledsupply also has some lenses available for the 3 up emitter along with a housing and a heatsink,  I didn’t buy the heatsink in lieu of my own computer heat sink but I did get the housing and some real thermal epoxy instead of just super gluing the emitter to the heatsink with a little thermal grease in the middle which is what I’ve always done.

I found that a spade drill for wood had no problem going through an aluminum heat sink..

Here's the emiiter. Its actually 3 emitters connected to one star board. Wires run through the housing and through the center of the emitter.Here's what the heatsink part of my light will consist of. LED emitters may be effiecent but that much light from such a small chip produces alot of heat which must be disperesed.

Now I've thermal epoxied the housing to the heatsink and the emitter board to the housing.I'm powering the light with a buckpuck which is a current emitter. Concted straight to a DC power source the chip will draw to much juice and fry itself.

Here's the whole system, a RC plane battery that cost about 12 bucks and the buckpuck along with powered switch wired between the battery and LED.

Here's the new lens, a seperate light collector for each emitter.

I zip tied the light for testing, with its flat profile it should be easier to attach to the top of a helmet as well.It may not seem so bright in this picture until you consider the exposure is the exact same as all the other pictures in this set which where taken under my bright work lights. Most lights would barely show up on that camera at this exposure.

 

It may not seem so bright in this picture until you consider the exposure is the exact same as all the other pictures in this set which where taken under my bright work lights. Most lights would barely show up on that camera at this exposure.

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About Matt Gholson

Cycling, school teaching, husband.
This entry was posted in Mountain BIking, Stories, technology (geek) and tagged , , , , , , , , , , , , , . Bookmark the permalink.

5 Responses to My best LED Light Yet

  1. Steve says:

    Very industrious! I hope it holds up for you. As a side note, I liked the Google hat with the 93 cent price tag still affixed to the bill! 🙂

  2. Pretty cool stuff. How heavy? Total cost? Run time?

  3. Matt Gholson says:

    Good Questions

    Weight: Very lite I’ll have to weight it.

    Cost: About 50 bucks but that doesn’t include the charger and heatsink which I allready had.

    Runtime: Not sure yet, probably about 2-3 hours on high, 4-5 on low?

  4. rlhoover says:

    I am impressed at your DIY ability. I am going to have to get a new tail light soon and am starting to think what to do with the old one. It still works, but I am using rubber bands to keep it together.

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