How hard can you drive a Luxeon V?

How much current can a Luxeon-V reasonably accept? I don't recall seeing any reports of one being driven above 1000ma.

Related question, can the Badboy handle this much power? I know it can drive a Lux-III at 1500ma, but a Lux V at 1250ma will be around 10 watts total power.

A 5Wer can be driven up to 1.5 amps fairly well.
Some of the SpaceNeedle type mods are hitting as much as 1.6 amps off 3x123 direct drive.

As long as the heat sink is doing its job, 1.5 amps is doable, the question is, weather its worth it.
If you just want a show light, thats BRIGHT, then go for it, but if you want a light to use, I would do 1 to 1.2 amps.
This saves LS life, and gives you more runtime, and unless you really take the time to compare them, you wont notice a difference in output.

Once you get about 1 amp, its gets harder to see the difference easily.

I wouldnt recommend a BB above 1 amp.
They get HOT, and are not very effecient at all at that level.

-John

Tyler,
I have a PM6 module somewhere that has 2 DB900's in parallel, if I recall correctly. The 1800mA to the 5W does give it more light output than a B750, but not really that much, IMHO. On the other hand, I think this particular build might be a good tool for boring through ice blocks! /ubbthreads/images/graemlins/icon15.gif Proper thermal relief will allow the LED's to survive (who knows how long) at elevated current levels but the thermal relief *is* required and necessary because you are punching out a bunch of phonons with the gain of a few extra photons, IMHO.

The law of diminishing returns is alive and prevalent in the world of luxeons. Even going from 700mA to an amp doesn't get you what you would like. I personally like the 900mA range. You get good light. Decent runtime and manageable heat. To get a meaningful increase in light from that, you'd need to double the current and the increase in light really doesn't enable the light to do anything that it couldn't do at 900mA.

Well, with an infinite heat sink held at 25C, perfectly bonded to the emitter slug, and assuming a Vf of 6.8V at 700mA, the absolute maximum current you could put through a LV without exceeding thermal spec is about 1.8A. Anything more and the junction temp exceeds 135C. Of course, at that power level, you probably won't even get to 500 hours before degrading to 70% output.

With normal heat sinks and thermal bonds, you probably exceed thermal spec at around 1.6A.

Don ... care to share a photo / beamshot / anything about that monster scorcher killer thing?
/ubbthreads/images/graemlins/evilgrin07.gif
bk

Bernhard, sorry I even mentioned the POS! /ubbthreads/images/graemlins/nana.gif Beam shot would look like any 5W in PR. The Lux reading was higher than a typical X3t in PR and in fact, it may be that I wasted a X3t on this McModule! /ubbthreads/images/graemlins/icon15.gif Instead of wasting any time on this dumb "test piece" I think I will get to work on your new Aleph 2 builds. /ubbthreads/images/graemlins/blush.gif

ok Don ... forget the photos ... you got me convinced.

one minute of silence for the poor X3T ... /ubbthreads/images/graemlins/icon15.gif

bk

Hmm...

I can't think of any way to cleanly wire two badboys in parallel in a PR head. /ubbthreads/images/graemlins/smile.gif

Most of the comments confirm what I thought before. I think 917ma is the sweet spot, both for Lux III and Lux V.

Don't forget the MR-X at 1.5A to the X3T!

X4T BB750 driven by R123 = 1.872amps @ 3.722v (as measured at batt by fluke 87)

yes it's bright! one of my fav combo's..