blesbok
Newly Enlightened
I've been lurking here on CPF for a while and decided to post the beginnings of a 3x MCE bike light I'm building.
Started with 1" x 3" section of copper core board from Bergquist. Etched the board to drive the LEDs in a 3s4p configuration (or is it called 4p3s?). I also ground away the dielectric to make a direct solder connection b/t the LED and copper core. My back of the envelope calculations suggest that, with 10W conduction through an area the size of the MCE pad, even a 3mil dielectric results in about a 20C differential, though I could have made a mistake.
Before mounting LEDs:
After reflow, before soldering legs:
With Ledil LM1 "diffused" optics:
And finally a beamshot comparison with a 20W halogen on the left (1.7A at 12V) and the 3x MCE light driven at ~20W (2A at 9.9V). Identical camera settings for both shots.
Cheers,
Brent
Started with 1" x 3" section of copper core board from Bergquist. Etched the board to drive the LEDs in a 3s4p configuration (or is it called 4p3s?). I also ground away the dielectric to make a direct solder connection b/t the LED and copper core. My back of the envelope calculations suggest that, with 10W conduction through an area the size of the MCE pad, even a 3mil dielectric results in about a 20C differential, though I could have made a mistake.
Before mounting LEDs:
After reflow, before soldering legs:
With Ledil LM1 "diffused" optics:
And finally a beamshot comparison with a 20W halogen on the left (1.7A at 12V) and the 3x MCE light driven at ~20W (2A at 9.9V). Identical camera settings for both shots.
Cheers,
Brent
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