RGB better than white?

[sharpstik]

(newbie here) haven't been able to find this out anywhere. white Luxeons are not as efficient as colored. I want to use three 1w Luxeons, R, G & B, balanced a bit, to make a 3 element "composite white" illuminator. should be as bright as a single 5w white, i would think. I'm thinking one Powerpuck pushing the 3 units, each with whatever resistor is needed to balance it. Can you run 3 1W luxes in parallel on a single PP, with resistors in parallel to? am i totally off the wall here?
And does Future Electronics sell small lots to individuals? I can't find much on their website that leads me to believe they do. http://www.markhannahsurplus.com seems the best place for Luxes.

 

[Rothrandir]

well, rgb means (as you know) red, green, blue.

luxeons for one, are almost never the colors they say they are. (they vary from led to led) and also, the ingan leds (reddish colors) won't like the same amount of power as the blueish/cyanish/whitish colors. and as such, it is impossible to run them all together. (unless the proper resistance is used)

luxeons will react differently to power sources: you could have two green luxeons, and put them both at 3.42v 350ma (these are the rated specs), and chances are they will have a different color and different brightness.

different colors are more *intense* than other colors. basically, if you wanted a blue and a green to be the same brightness, one might want 500ma, while the other only wants 325ma.

red will not like nearly as much power as the green or blue, and as if you try to force-feed it too much power, it will vomit the magic smoke.

basically, it is just a little bit less than impossible to get it matched. to many variables: color, voltage, output of led...

future will sell small amounts, but call them for a better price.

white 1w luxeons are rated at around 18 lumens (can be anywhere between 10 and 32...), where as 5w whites are rated at 120 lumens (can be anywhere around there). these numbers are basically averages of luxeons when driven at specs.

your best bet for white is a white emitter. 5w if big output is what you want.

 

[sharpstik]

Good points. I do have some 5w whites in the mail for illumination. One idea I want to play with is to be able to mix the RGB for different colors. Either way, what is the best circuitry for adjusting brightness? current regs, voltage regs, or PWM? and what are the best ones? I like the Powerpuck, but i don't think it is adjustable. Resistors seem a very wasteful way to dump energy.
Is there an up to date FAQ on this somewhere?
thanks
billy sharpstick

 

[EMPOWERTORCH]

I'm just wondering whether the control circuit of an Eternalight Raven (a microprocessor controlled multicoloured multifunction LED torch) would be moddable to control Luxeons instead of Nichias. The step-up in power might call for transistors mounted on a separate board to drive the Luxeons, and the battery supply may need to be increased for power purposes.
I believe that there is someone selling the uC's somewhere on this forum complete with a programmable torch kit!