5W Luxeon Cateye mod. 1st try

[Pinter]

Hi all,
I have been inspired on Sprout's Cateye 1W luxeon mod so I decided to try my own first mod.
I had a Cateye HL-1600 halogen bicycle lamp. This lamp has 5xAA holder as was made for rechargables to drive a 6V 2.8W halogen bulb. Having a low Vf (~6.11V) luxeon 5W emitter I hoped that 5xAA will be enough to drive it. Unfortunately body of the light accepts only small optics. Having not too much choice here I got an Energizer 2xAA pocket light from a local store and used optics from it. For heatsinking I used some vga or chipset heatsink I found at home.

First I had to make place in the body. Having no appropriate tool for cutting plastic I used my Weller soldering iron for it (very nasty thing; I am not proud of it /ubbthreads/images/graemlins/smile.gif. Melted a rectangular hole atop the body for the heatsink. Thus part of the heatsink resides outside allowing to be cooled by the wind. Next I shortened the transparent front plastic to allow enough space for the inner part of the heatsink. Further melting was necessary to remove shapes that held the bulb connector formerly.

Then I used Arctic Alumina epoxy for bonding 5W emitter to the heatsink.
Cut away my poor Energizer 2xAA head, made the optics inner hole bigger to accept the Luxeon dome. Then started to shorten the optics head. Tested it many times on the emitter of a headless Megalite, until I got the brightest overall light in the kitchen. I found out quickly that this small "optics" is not a throwing champion. After I got the ideal height I soldered wires to Luxeon connections and tightened the optics on the heatsink with AA epoxy.

I made the config together, measured currents and millivolts and found that wiring has too much resistance. Replaced the non-moving critical wires with a good quality thick loudspeaker cable.

And yes, it worked. Partly.
Unfortunately LED Vf is not low enough, voltage of 5xNiMH batteries under load reach the Vf sooner than I expected.
Now I am seeking a way to stuff a sixth cell. Perhaps will implant a uFlex regulator inside after that. I plan further improvements e.g. making the heatsink not reach out of the box and inserting a 25mmx25mm notebook fan into the body.
Final product is here:
http://kep.tar.hu/pinyo/index.phtml?aid=27627249&pid=4393461&beginnum=12

You can see other pictures of the project:
http://kep.tar.hu/pinyo/index.phtml?aid=27627249
(Just click on the possibly missing thumbnails, pics are there)

 

[lambda]

Pinter - Very nice!

Looks like your project is coming along very nicely. That should light up some trails for you.

 

[Steelwolf]

Maybe you can ask around for the innards of the KL4. There may be a few floating around as a couple of people have swapped out the 5W LS in the KL4 for a LuxIII. In the process, the electronics need to be changed as well to accommodate the lower Vf of the LuxIII.

Using such an innard, you would have more than enough power and Vbatt from 5xAA, since the KL4 starts with 6V and runs all the way down to under 3V.

 

[Pinter]

Yes, I am also thinking on a LuxIII. Unfortunately I do not own any right now.

 

[Sprout]

Gosh, it's flattering to hear that my mod was an inspiration
/ubbthreads/images/graemlins/smile.gif

Your mod looks very nice, Pinter, and I like the way the heatsink is exposed. For the 1 Watt Luxeon I didn't think it was necessary, but my next project will be with a LuxIII (when I can find one) and it will have to be better cooled.

I'd like to buy some leds and Fraen optics from this place, but they haven't answered my mails - I'll have to give them a call:

http://www.dianaelectronic.de/led/