Results: Testing XM-L, MC-E, SST-50, and XP-G emitters **Updated**

Awesome job Match thanks

maybe slightly off topic and out of date but is there any test like this with XR-E Q5 emitters as i see alot being driven past 1 amp and all the data sheet,s i see are one amp max i would like to see flux and maybe heat ratings from a Q5 when you push them hard can any one point me in the right dirrection ?

Joining this poorly disguised plea for Match to include the XR-E in this eminent research.

I have a couple of the latter overdriven from stock as well. Laughing

just found this page courtesy of a member of my forum linking it.

well done! The data with the XM-L matches my own testing :)

I can see why I dislike the SST50's performance so much, too :)

C

Match you are awesome!

I just read the whole darn thread and I´m just still baffled by your dedication to "knowing" and your easy way of passing the info on down the tube.

Aplaudable indeed

Thanks Match. I always wondered if an sst50 could be driven to approach the surface brightness of an XRE. This might do well for a thrower, but then you are well into the power requirements for a descent HID.

Outstanding job Match, I learned a lot after your post. Thanks

Match,

While taking a second look at your test results, Ive decided to scrap the ideas of building a mega high output SST-50 thrower. When examining efficiencies while driven at high current levels, the SST-50 simply isn't a logical choice when compared to the SST-90 or an HID.

I assume that you used the XM-L U2 1C during your tests? Since most people will probably mod using a driver with 8 x 7135's, its very interesting to compare your measured lumen outputs at 2.8A.

Emitter Lumens

XM-L 852

MC-E 693

SST-50 708

A few interesting realizations (for me):

* To achieve the same luminosity of the XM-L @2.8A, the SST-50 needs approximate 3.6A, while the MC-E requires 4.4A.

* The XM-L gains only 29 lumens when going from 2.8A to 3.0A.

Typical flashlights lumens will suffer far greater losses as heat rises. More often, high junction temperatures are reached fairly quickly. Considering the XM-L, it really does make sense to run at lower amps, especially for applications that run continuously for long periods of times (searchlight, bike lights, etc.) This gives me some great ideas for my next 3 x XM-L bike light. Thanks for all your hard work.

Very informative thread. Thank you very much!

Do you plan on adding more LED types to the tests? XR-E R2 (WG) perhaps, and SST-90?

thanks very much for running these tests. This is incredibly useful for making informed decisions.

I have a question though, that I don't 'think' has come up here - if the emitter(s) were actively, and well cooled, would we see a higher peak output? Ok, it would seem obvious it would increase at least some, but I wonder how much.

Really though, what would be useful, is if it extended the nonlinear relationship of input/output. Instead of plateauing around 2.4-2.8...to say 3.5

Fair enough question....but, for the tests conducted thus far active cooling via fan and/or water would make no appreciable difference. For the given runtime on the above tests, the thermal capacity of my heatsink setup can be considered infinite (as confirmed via thermocouple/fluke monitoring). The bottleneck is the pcb.

Now having said that, I'm staring at a box containing just over half a dozen peltier coolers leftover from a different project. Using one, or better yet, stacking them can yield near cryogenic temps on the top plate where the star could be mounted. Considering each peltier requires 150w, the power requirements (and cost) launches the idea out of the realm of flashlight practicality. Although the results would be interesting for curiosity's sake, I don't see myself getting that bored yet to try.

Thanks very much for the response. I've had an internal debate for weeks on buying copper PCB xmls (instead of aluminum) for a project. I think it will be worth the extra money to buy copper.

I think you're right about the impracticality of a peltier. But let's hope for some new advancements in battery technology to change that :)

Even if they do, it will probably be up to us to build such things - at least on MY budget...

Folks,

Updated with XP-G data in the first post. I also cleaned it up a bit, like fixing that horrible non-linear graph for the xm-l.

-Match

Great. Thanks Match.

This post has really become my reference post when deciding about current levels.

Thanks a lot M8 :-)

That's crazy I have been pushing XPGs to 2.2 amps (8 chip Nanjg driver with 2 removed) because that's were they looked the brightest by eye and it was right on the money.

Many thanks for this addition, Match!

(Standing by for the XR-E ... Smile )

I would really love to se an XP-E or XR-E q5 led in the mix. :) I still like them.

Thanks Match! Been waiting for this info to build my XP-G project. Question now is, is it worth the sacrifice of runtime to get a little more light. I'm looking at 600mA to gain about 50 lumens. I don't think it's worth it. Still seams like 1.4A is the sweet spot for runtime vs. output.

-Garry

2.2A xpg is exactly what the N-light B2s stainless steel lights are running on the 14500 ..

always got a ..."WOW that's bright".... from the crowd ...

ooooohh....aaaahh.