5W Luxeon not that bright!

[robk]

Got a white 5 watter in today. Rigged it up to 7.2V NiMH with a conservative 3 ohm/5 watt resistor. Tried NX01 and NX05 optics, really not that bright. (Waiting on 30mm collimator) It seems to emit about 2 watts light and 3 watts HEAT!!! This is mounted on an aluminum disk in a MAG, but it generates a lot of heat, drawing about 590mA cold, rising to about 630mA warm. Anyone else disappointed?
Rob

 

[Snewt1]

Um, first off, what bin code ya got?
then drive it to spec, at least 700mA.
Did you use artic silver or something like it to mount the led?, and the AL disk?

If not, forget what I said and under drive it more.

Any way, I think the problem is that 3 ohm resistor. Back of some. You don't have to go direct drive if ya don't want, but there is a go bit of difference(to the naked eye) between 800-900mA and 600-700mA. Anyway, check out this: Click Here I have some beamshots with a 5W in a mag, beam shots at around 880-930mA.

Hope this helps a little. /ubbthreads/images/graemlins/help.gif

 

[ufokillerz]

the 5W luxeons work best with reflectors IMO, and i think your judging it by throw and hotspot. Not sure what you mean by "light" but lumen output would be restricted by other factors such as reflector/ optic. If i compared a 5W in mag2c against a 5w with nx-01 or 05 optics, the difference will be like night and day.

 

[FalconFX]

I think the 5W you've got is underdriven, aside from having a resistor that isn't really necessary at 7.2V from NiMHs...

Try running it at 7.2V without any resistor... Most of the brightest mods here are running off of 9V direct drive, but even if you were running it off of 9.0V, you can slap on some resistance and still have it blaring bright...

Seems like either a really underdriven LS or a semi-DOA one... The bin codes will definately tell more...

 

[robk]

Thanks for the responses. A 30mm collimator came in today and made a huge difference. I'm also going to drop the resistor to 2.2 ohms, I want the extra run time (compared to .5 ohm or no resistor) and also, I feel it's bad practice to grossly over drive these LEDs. I have 3 1 Watt ZLT based lights that I run up to 440mA, but these emitters are cheap! The 5 watt ones are more money, shorter life and run hot. I guess I'll be happy with the larger optic and 2.2 ohms which should drive the LED at about 700 mA or so.
Rob

 

[robk]

Well, against my better judgement, I installed a 0.5 ohm resistor, using a 7.2V Nimh battery pack. This combined with the 30mm optic, I must say is extremely impressive. It is blindingly bright! Runs a little hot, but it's a toy. I never thought I could get this much light from an LED. Absolutely incredible!
Rob

 

[bucken]

Rob,
I think I know how you feel. I'm driving a 5W V3 bin in a Blaster VI with 9V direct-drive. The heatsinking in the Blaster's, however, is outstanding.

 

[robk]

I'm using an Elektrolumens aluminum disk with heat sink compound press fit into a Mag, so there is a lot of aluminum to dissipate the heat. Generates quite a bit of heat - I didn't check the current draw with a current sense resistor (don't want to know!) Gotta be around 900 mA with fresh charged NiMH cells. So far, so good. No smoke!
Rob

 

[Snewt1]

Wooo Hooo...Cook it baby!!
Once ya go bright ya never go back.

 

[robk]

Yeah, but I wouldn't trust this light on a critical mission! I'll fill my pockets with Mini-Mags with ZLT or BB400's. I consider it a "WOW" light to blind my friends.
Rob