I recently became interested in building a big flood light when I saw the great host idea that Mattaus had in his thread here. The work-light style host works well for an LED array mod.
This light uses a laptop power supply or a laptop supplemental battery pack I picked up at wal-mart. My kill-a-watt measures 25w on med, and 75w on high. Here is a picture of this light...
Cooling this many LEDs in this small of a package can be difficult. I had a large heatsink left over from something else, and I found it fits almost perfectly mounted to the back of the light. The LEDs are directly mounted to the heatsink, and the fan easily keeps the heatsink cool. The whole thing barely warms up even on high for hours.
Here you can see the H6CC driver which powers the LEDs (right side), and the voltage regulator that powers the fan. Together the light has an input range of 10v-22v.
Here is the H6CC heatsink, external dimming POT, and power jack. Also, the fan overhangs the heatsink a little because it helps keep the H6CC heatsink cool.
I used 3 slightly different tints in my LED array to give a richer color rendition. Two were cool, and four were neutral. The light appears appears very white until you compare it to a truly cool white source.
Some outdoor shots (sorry about the focus)
I decided to try a diffuser:
I still need to seal the seams a little to help keep out humidity and dust. At least the seams are tight enough to keep most bugs out.
I have already used it once or twice, once at a cookout that went past dark. I'm looking forward to taking it (car) camping.