Step 4: Solder the LED's together

Picture of solder the LED's together
fit to heatsink. the led's are in a series-parallel configuration (2 led's in series, 2 pairs of that in parallel)

note that if you want to make a white headlamp, or any other color, the project will work exactly the same.
trondk7 years ago
What about the ZLED P4 series leds from Seoul Semiconductors, could they work? The P4 emits 240 lm at 1A. I have built two of these headlamps with lumileds, one white and one cyan. Fantastic light. Now I am wondering if the P4 leds will be even brighter. Do you think the BuckPuck can drive 7 these puppies like the Betty X Pro from Lupin? P4 leds at http://www.zled.com/ See the Betty at http://www.lupine.de/ - It must be cheaper to build one...
chrism8 years ago
Took me a while to work out that you're running two diode pairs in parallel. That's really bad practice, as a slight variation in the Vf of the LEDs will result in one pair getting a lot more current than the other. Run them all in series instead and get a 350mA boost driver, or use two separate 350mA buck drivers.
dan (author)  chrism8 years ago
at the hobby level it is not a problem. led's from the same manufactured lot are usually identical voltage drop. if you are worried you can test them beforehand. you see plenty of commercial products that put them in parallel although i agree it is not a good idea at a large scale. the buckpuck spec sheet even suggests putting them in parallel. you can also use a low-value resistor if you are worried, 0.5 ohm on each leg