Meltdown

Well maybe my LED headlight was not the best design. It worked great for about 5 hours of commuting to work and back and then began to dim. I thought that maybe my battery was dying, but that is not the case. Further investigation has shown that:

• The forward bias voltage of the LED has increased by about 0.5 volts.
• The light output is erratic over the current range.
• The lens has begun delaminating from the package.
• Solder flux has made a mess all over the aluminum board.

My conclusion is that this is a case of thermal overload. The thing is running just too damn hot.

Back to the drawing board, but what to do? I could drop down to a Luxeon I, which would have much less thermal issues, but also much less light output. I could re-install a new Luxeon III and run at a lower current. Maybe 700mA instead of the 900mA I was running it at. Somehow get a more efficient heat sink into the light... maybe a fan? This may be difficult due to space constraints.

Argh... I did not realize that 3 watts of heat would be such a problem to dissipate.