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Thread: White LED lumen testing

  1. #121
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    Default Re: White LED lumen testing

    I added 2 samples (ISP 2-die 22,000 mcd 25° 5mm white, LCK 55,000 mcd 15° 5mm white) sent to me by CPF member TMorita to the list in the first post and updated the graphs accordingly. You might need to refresh your browser to see the updated graphs. The relevant spreadsheets were added to the .zip file linked to in the first post of this thread.

  2. #122
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    Default Re: White LED lumen testing

    I added the Jeled 55,000 mcd 15° 5mm whites sent to me by CPF member Minjin to the list in the first post and updated the graphs accordingly. You might need to refresh your browser to see the updated graphs. The relevant spreadsheets were added to the .zip file linked to in the first post of this thread.

  3. #123
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    Default Re: White LED lumen testing

    Quote Originally Posted by TMorita
    I don't think the LVEHK 140ks were rated at 80ma.

    Here's a link to the specs:

    http://cgi.ebay.com/100p-10mm-SUPER-...QQcmdZViewItem

    The DC forward current is 20ma.

    Toshi
    Corrected-Thanks!

  4. #124

    Default Re: White LED lumen testing

    One note:

    The ISP 22ks are actually rated for 100ma AFAIK. They are not the 40ma ones on the website. I had to special order them.

    The 40ma ones on the ISP website are dual-die:

    http://www.powerleds.com/

    However, if you look at the ISP 22K LEDs, you'll see there is only a two bond wires visible - one from the cathode, one from the anode. So it appears to be a single large die, and not two small dies.

    Toshi
    Last edited by TMorita; 04-24-2007 at 10:01 AM.

  5. #125
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    Default Re: White LED lumen testing

    Quote Originally Posted by TMorita
    One note:

    The ISP 22ks are actually rated for 100ma AFAIK. They are not the 40ma ones on the website. I had to special order them.

    The 40ma ones on the ISP website are dual-die:

    http://www.powerleds.com/

    However, if you look at the ISP 22K LEDs, you'll see there is only a two bond wires visible - one from the cathode, one from the anode. So it appears to be a single large die, and not two small dies.

    Toshi
    Thanks again, I corrected the write-up to match the new info you gave me.

  6. #126
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    Default Re: White LED lumen testing

    I added 3 samples ( Hebei 520MW7C 20° 5mm white, Hebei 530MW7C 30° 5mm white, Hebei 550MW7C 50° 5mm white ) sent to me by CPF member LEDude to the list in the first post and updated the graphs accordingly. You might need to refresh your browser to see the updated graphs. The relevant spreadsheets were added to the .zip file linked to in the first post of this thread.

  7. #127
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    Default Re: White LED lumen testing

    Lumileds Rebel White LXML-PWC1-0100 (acquired July 2007)

    Note: Earlier results multiplied by correction factor of 1.116 and post edited accordingly (See post #138 for explanation).

    I purchased a pair of these from Future Electronics for evaluation. I only tested one of the two samples. Color bin was not specified, but these are similar in color to the WH Crees, so I'd guess that they are V0s. I soldered the Rebel to a small length of brass bar with two holes drilled in the ends. I screwed the bar to my heat sinked power LED test jig with some thermal grease at the interface for better heat transfer. Beam angle measured 100.1°, a bit narrower than Luxeon IIIs, and the beam pattern is close to, but not exactly, lambertian. In the course of testing I learned how important it is to keep the lens of these LEDs clean. My initial test results gave roughly 91 lumens at 350 mA. I tried cleaning the lens with alcohol and then rerunning the tests. The final results were 96.7 lumens at 350 mA, but I later determined that I needed to apply the correction factor for my light meter. This revised the results to 107.9 lumens which is within spec. At 700 mA the Rebel put out 183.1 lumens, just about dead on the specified 180 lumens. Output continued to increase with current, reaching over 290 lumens at 1500 mA, which is as high as my current source goes. Moreover, the output curve wasn't entirely flattened out, even at 1500 mA. I would guess that output would continue to increase to 2 amps, albeit not very much over the output at 1.5 amps. Vf was extremely low and didn't rise very fast with current. It was 3.14V at 350 mA but only 3.43V at 1500 mA. Efficiency at 350 mA was 98.2 lm/W, a new record for power LEDs, and tantalizingly close to the magic 100 lm/W. Interestingly, with the apparent stagnation in small LED efficiency since early 2006, power LEDs are now actually more efficient than indicator-type LEDs. Moreover, efficiency at 1000 mA, the maximum specified operating current, was still a very decent 69.4 lm/W, about on par with CFLs, and stayed above 56 lm/W even at 1500 mA. Maximum efficiency was reached at 20 mA, and it was an incredible 150.7 lm/W. This translates into a conversion efficiency of over 45%. Efficiency remained above 100 lm/W until around 325 mA. Overall the Rebels have broken all previous records, but I suspect their time on top will be short-lived as I have yet to acquire the Cree XR-E Q5s for testing.


    Original post:

    I purchased a pair of these from Future Electronics for evaluation. I only tested one of the two samples. Color bin was not specified, but these are similar in color to the WH Crees, so I'd guess that they are V0s. I soldered the Rebel to a small length of brass bar with two holes drilled in the ends. I screwed the bar to my heat sinked power LED test jig with some thermal grease at the interface for better heat transfer. Beam angle measured 100.1°, a bit narrower than Luxeon IIIs, and the beam pattern is close to, but not exactly, lambertian. In the course of testing I learned how important it is to keep the lens of these LEDs clean. My initial test results gave roughly 91 lumens at 350 mA. I tried cleaning the lens with alcohol and then rerunning the tests. The final results were 96.7 lumens at 350 mA. Since this is less than Lumiled's tolerance for lumen measurement this is still within spec. More importantly, at 700 mA the Rebel put out 179.63 lumens, just about dead on the specified 180 lumens. Output continued to increase with current, reaching over 260 lumens at 1500 mA, which is as high as my current source goes. Moreover, the output curve wasn't entirely flattened out, even at 1500 mA. I would guess that output would continue to increase to 2 amps, albeit not very much over the output at 1.5 amps. Vf was extremely low and didn't rise very fast with current. It was 3.14V at 350 mA but only 3.43V at 1500 mA. Efficiency at 350 mA was 88.0 lm/W, a new record for power LEDs. Interestingly, with the apparent stagnation in small LED efficiency since early 2006, power LEDs are now actually more efficient than indicator-type LEDs. Moreover, efficiency at 1000 mA, the maximum specified operating current, was still a very decent 62.2 lm/W, about on par with CFLs, and stayed above 50 lm/W even at 1500 mA. Maximum efficiency was reached at 20 mA, and it was an incredible 135 lm/W. This translates into a conversion efficiency of over 40%. Efficiency remained above 100 lm/W until 200 mA. Overall the Rebels have broken all previous records, but I suspect their time on top will be short-lived as I have yet to acquire the Cree XR-E Q5s for testing.







    Last edited by jtr1962; 10-01-2007 at 01:08 PM.

  8. #128
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    Question Re: White LED lumen testing

    Wow! This is awesome work you are doing jtr1962!

    Can you recommend a 5mm LED to upgrade my eternaLights with? My last mod replaced the originals with the 25kmcd's.

  9. #129

    Default Re: White LED lumen testing

    Quote Originally Posted by RonM View Post
    Wow! This is awesome work you are doing jtr1962!

    Can you recommend a 5mm LED to upgrade my eternaLights with? My last mod replaced the originals with the 25kmcd's.
    I put the 20x40k's in mine when I order the blaster kit from EternaLight.
    Ray
    Good people need to be there for each other. It's the only way to stay sane in a sometimes insane world.

  10. #130
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    Default Re: White LED lumen testing

    Quote Originally Posted by RonM View Post
    Wow! This is awesome work you are doing jtr1962!
    Thanks!

    Can you recommend a 5mm LED to upgrade my eternaLights with? My last mod replaced the originals with the 25kmcd's.
    Based on what I've tested, the Jeled 55Ks are about the best available 5mm LED right now.

  11. #131

    Default Re: White LED lumen testing

    Quote Originally Posted by jtr1962 View Post
    ...Based on what I've tested, the Jeled 55Ks are about the best available 5mm LED right now.
    Yikes at those shipping costs, though!
    Ray
    Good people need to be there for each other. It's the only way to stay sane in a sometimes insane world.

  12. #132
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    Default Re: White LED lumen testing

    Thanks for all this good work JTR.
    That Rebel looks like a great LED for a well designed light.

  13. #133
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    Default Re: White LED lumen testing

    jtr1962 ... it clears up a lot of miss-information that i was having.....

    great work.

  14. #134
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    Default Re: White LED lumen testing

    Good results on the Rebel! However I think the Q5 will beat it. Waiting for that test...

  15. #135
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    Default Re: White LED lumen testing

    Hi jtr1962,

    It seems that every 5mm LED has a peak lm/W at a round 4-5 mA-ish.

    Is this peak the optimum current to run 5mm LEDs at?

    For example, I have a 128-LED shower head torch that drives each LED at 4mA. It works very, very well.

    But although this seems to be the optimum for power consumption, will it also maximise LED life?

    Any thoughts?

    (I am thinking of low-power solar lighting, etc.)

  16. #136
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    Default Re: White LED lumen testing

    Quote Originally Posted by Erasmus View Post
    Good results on the Rebel! However I think the Q5 will beat it. Waiting for that test...

  17. #137
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    Default Re: White LED lumen testing

    Quote Originally Posted by lctorana View Post
    Hi jtr1962,

    It seems that every 5mm LED has a peak lm/W at a round 4-5 mA-ish.

    Is this peak the optimum current to run 5mm LEDs at?
    For any LED the lower the current the longer the lifetime. Lifetime is probably maximized by running at 1 mA but of course you end up needing a lot more LEDs. 5 to 10 mA seems to be a good balance between lifetime, efficiency, and cost. Also, the majority of 5mm LEDs seem to have their best efficiency around 4 or 5 mA, but there are a few which do a little better as low as 1 mA.

    I made some LED train lights recently which run the LEDs at 10 mA. This combined with wide PC board traces to dissipate the heat should result in reasonable lifetime (hopefully 10,000 to 20,000 hours) before noticeable dimming occurs. This is more than sufficient in this application. You may be able to get a few hundred thousand hours by dropping down to 1 mA. However, for most applications this is overkill. Remember that at 6 hours a night a 100,000 hour lifetime equates to nearly 46 years. The item being lit will most likely either be obsolete or lost or broken long before then.

  18. #138
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    Default Re: White LED lumen testing

    I changed my setup somewhat immediately before the tests of the Rebel 100 and the Hebei LEDs. I set up a series of baffles and totally enclosed them to block out any ambient light:



    I even put a removeable cover to block ambient light near the light meter:





    The purpose of these modifications was to eliminate guestimating the background light which needed to be subtracted from the light meter reading. For 5mm LEDs this was at most about 0.5 lux, but for power LEDs it was considerably more. Prior to this, I would block out the direct portion of the beam with a piece of cardboard, note the reading, then subtract it from the unblocked reading. This method always bothered me because it introduced another variable. While the background reading was fairly steady, it did vary enough depending upon the placement of the cardboard to cause concern. Hence my use of the term guestimating at the start of this paragraph. The modified setup introduces consistency. When I block off the small hole where light enters from the LED, the reading is at most 0.1 lux, even in a undarkened room. I still do my testing in a darkened room, but with the new setup I don't have to!

    Now this is all good and well except that when I tested the Rebel 100 I was getting somewhat less than the minimum of 100 lumens (96.7 lumens @ 350 mA to be exact). However, according to the results of the CPF light meter testing which I had participated in my light meter was reading low for white LED light. The correction factor was 1.116. I applied the correction factor to my Rebel 100 results in post #127 and the numbers are more in line with what I should have gotten.

    The only question remaining was whether or not I could reliably compare my earlier results with my new ones. To answer this question I decided to retest the P4 bin Cree XR-E which I had tested last November. The original results were 85.67 lumens at 350 mA. The uncorrected results using the modified tester were 80.24 lumens at the same 350 mA. This was about 6.4% low. The corrected result was 89.55 lumens, within 4.5% of my original results. I also ended up with a somewhat narrower beam angle (new results in red, old in blue):



    It seems then that although I did not apply any correction factors to my earlier results the inherent methodology resulted in slightly wider beam angles which more or less compensated for the lower absolute lux readings. Remember that all of my earlier power LED test results pretty much fell within the ballpark of where they were supposed to for a given bin. The only problem is that LEDs obviously come in different tints, and I suspect I would need different correction factors depending upon the tint. Based on the fact that my light meter was nearly dead-on with incandescent light, the correction factor would increase with increasing color temperature. However, since guestimating correction factors would make this testing more art than science, I'll stick to using the official correction factor of 1.116. The fact that my corrected result for the P4 Cree is a little high probably has to do with that LED being a warmer (WH) tint bin.
    Last edited by jtr1962; 10-03-2007 at 10:30 AM. Reason: spelling

  19. #139
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    Default Re: White LED lumen testing

    Cree 7090 XR-E Warm White bin P4 (acquired September 2007)

    I ordered some Q5 Cree XR-Es from CPF member Erasmus. Along with the Q5s Erasmus sent me a Cree XR-E warm white bin P4 for testing. The P4 bin is specified at 80.6 to 87.4 lumens at 350 mA. The color temperature looked like roughly 3300K, so I would say the tint bin was 7A. Since the color temperature was in the incandescent range, I didn't need to apply a correction factor. The output of 83.0 lumens at 350 mA is solidly within the P4 flux bin.

    Results are shown below:






  20. #140
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    Default Re: White LED lumen testing

    jtr1962, great work. many thanks.

    just wondering why the Vf is on higher side in warm Cree XR-E P4's...

  21. #141
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    Default Re: White LED lumen testing

    Cree 7090 XR-E bin Q5 (acquired September 2007)

    I ordered 10 Q5 Cree XR-Es, bin WG, from CPF member Erasmus. The Q5 bin is specified at 107 to 114 lumens at 350 mA. The color temperature of the WG bin is roughly 6000K. The results are a little low (105 lumens at 350 mA), but remember that this is a cooler bin. My correction factor is probably a little too low for such a cool tint, and this is what accounts for the discrepancy. In any case, the difference between the actual measurement and the manufacturer's specification is less than 2%, and my setup is far from 100% accurate anyway. Even if this difference is real, it is well outside what would be noticeable with the eye.

    Vf is 3.20V @ 350 mA, efficiency is a very impressive 93.7 lm/W. Note that this is a little less than the corrected results for the Rebel 100 (98.2 lm/W @ 350 mA). However, the Rebel's higher efficiency is nearly all due to its lower Vf (3.14V @ 350 mA), and the fact that it is a warmer tint (and hence reads a little higher on my light meter). Also note that despite the slightly lower output at 350 mA the Cree bests the Rebel in terms of raw output at higher currents (298.5 versus 290.5 lumens at 1500 mA). The Rebel 100 still has a slight edge in efficiency at 1500 mA (56.5 versus 54.7 lm/W) due to its Vf increasing less with current than the Cree Q5. I took the Cree all the way to 2000 mA and it managed 334 lumens.

    Results below:






  22. #142
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    Default Re: White LED lumen testing

    Quote Originally Posted by ViReN View Post
    jtr1962, great work. many thanks.

    just wondering why the Vf is on higher side in warm Cree XR-E P4's...
    The P4s have 3 bond wires instead of 4. This and variation among chips probably account for it. I also noticed that the Cree warm white has a different colored phosphor (slightly more orange in color), although this has nothing to do with Vf.

  23. #143
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    Default Re: White LED lumen testing

    Quote Originally Posted by Erasmus View Post
    Good results on the Rebel! However I think the Q5 will beat it. Waiting for that test...
    The Q5 actually does beat the Rebel at higher currents in raw output, and comes very close in terms of efficiency. Also, due to the way my light meter responds I think my results would have been a little higher if it had been a WH tint instead of WG. I think a WH tint Q5 hand selected for low Vf could easily crack 100 lm/W at 350 mA.

  24. #144
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    Default Re: White LED lumen testing

    The warm white XR-E has an interesting beam profile. Is the "step" visibly noticable? Is the warm white using the conformal phosphor coating like the cool whites?

    My Q4 XR-E has a higher Vf than my P4 did, even though it had 4 bond wires vs. 3 - Vf is influenced more by the individual die than by the number of bond wires. Some have noticed a trend that the Q4s and Q5s tend to have a higher Vf than lower binned XR-Es.

  25. #145
    Flashaholic* Erasmus's Avatar
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    Default Re: White LED lumen testing

    Quote Originally Posted by jtr1962 View Post
    The Q5 actually does beat the Rebel at higher currents in raw output, and comes very close in terms of efficiency. Also, due to the way my light meter responds I think my results would have been a little higher if it had been a WH tint instead of WG. I think a WH tint Q5 hand selected for low Vf could easily crack 100 lm/W at 350 mA.
    Does the lightmeter respond better to lower color temperatures? There should be a correction factor for the high color temperatures, because these Q5's put out at least 107 lumen at 350 mA. From the LEDs from my group buy I tested 5 of my own LEDs and none of them comes above 3.26V @ 350 mA, while most people say their Vf is higher than lower binned XR-E's. Maybe these are from a different production with a lower Vf? Anyway I also have tested 2 with around 3V @ 350 mA, one only 2.98V! They put out at least 107 lumen and the power consumption for this particular one is 1.043W which results in an efficacy of 103.48lm/W @ 350 mA! Woohoo!

    Jtr1962, thanks for these great tests!

  26. #146
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    Default Re: White LED lumen testing

    Remember:

    http://www.cree.com/products/pdf/XLamp7090XR-E.pdf

    Page 2:

    "Cree maintains a tolerance of +/- 7% on flux and power measurements"

    Thus, that 107-114 lumens bin could still contain samples in the range of 100-120 lumens.

  27. #147
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    Default Re: White LED lumen testing

    Is the blue only (no phospher) LED version of any of the better 5mm white LEDs available.
    Ron Schroeder
    Brookhaven National Lab

  28. #148
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    Default Re: White LED lumen testing

    Quote Originally Posted by evan9162 View Post
    The warm white XR-E has an interesting beam profile. Is the "step" visibly noticable? Is the warm white using the conformal phosphor coating like the cool whites?
    The step is slightly noticeable (it looks like a faint ring). The phosphor coating method looks very similar to the cool-whites, so yes, I would say it's conformally coated. I also noticed that my P4 warm white does have four bond wires, same as the Q5s.

    My Q4 XR-E has a higher Vf than my P4 did, even though it had 4 bond wires vs. 3 - Vf is influenced more by the individual die than by the number of bond wires. Some have noticed a trend that the Q4s and Q5s tend to have a higher Vf than lower binned XR-Es.
    Possibly true. Another one of my Q5s tested slightly lower than the first one (103.77 lumens) but Vf was also lower (3.16V versus 3.20V), making efficiency nearly the same.

  29. #149
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    Default Re: White LED lumen testing

    jtr1962,

    I had a chance to test the WG Q5's ordered from Erasmus by a friend that I was doing a mod for, and I was rather bothered by a few things. I also noticed that the Vfs were unusually higher than older XR-Es. Out of two Q5s that were next to each other on the cut section of reel, I measured 3.48V for LED A and 3.38V for LED B. LED A had an annoying overly blue-purple tint, while LED B had an annoyingly overly green-ish tint. LED B was actually noticeably brighter than LED A when able to compare them side by side using a special paper shade that blocked the light (casted a shadow) that allowed me to directly compare the two on my ceiling or wall. Finally, the beam from both (with or without an optic) shows a distinctive checker pattern on the wall. Have you noticed such oddities as this?

    All things were not negative. Both oddly colored LED A and B (Q5s) were easily noticeably brighter than a perfectly white Q2 LED that had a lower Vf. So my friend got what he paid for: a brighter LED. It is too bad you have to sacrifice color an efficiency for brightness nowadays.

    Well, thanks for presenting this updated test rig to us. It is great to see that you are willing to improve the quality of our tests. How does these new numbers (from the fully enclosed box) compare to the results from evan9162 or Newbie? Are you willing to pass around a few LEDs, such as the XR-E P4, the XR-E Q5, and the new Rebel 0100, to evan9162 and Newbie? This is not to dis-prove your own results, but instead to allow us other hobbyists to get the most accurate information from the only three persons that are willing to measure the Lumens of the high power LEDs that we use often. This is for more consistent numbers between testers (which inconsistency seems to come from the two variables: color and Vf). Thanks again!

    -Tony

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    Default Re: White LED lumen testing

    Quote Originally Posted by Gryloc View Post
    jtr1962,

    I had a chance to test the WG Q5's ordered from Erasmus by a friend that I was doing a mod for, and I was rather bothered by a few things. I also noticed that the Vfs were unusually higher than older XR-Es. Out of two Q5s that were next to each other on the cut section of reel, I measured 3.48V for LED A and 3.38V for LED B. LED A had an annoying overly blue-purple tint, while LED B had an annoyingly overly green-ish tint. LED B was actually noticeably brighter than LED A when able to compare them side by side using a special paper shade that blocked the light (casted a shadow) that allowed me to directly compare the two on my ceiling or wall. Finally, the beam from both (with or without an optic) shows a distinctive checker pattern on the wall. Have you noticed such oddities as this?
    So far I haven't noticed such radical tint variations or poor beam patterns, but given that the Q5 bin is cutting edge this wouldn't surprise me. All my Q5s so far seem to be similar in tint. The only beam irregularities are the usual rings which the Crees have. As for Vf, one of my Q5s tested at 3.20V at 350 mA, two others at 3.16V. I haven't tested the others yet.

    Well, thanks for presenting this updated test rig to us. It is great to see that you are willing to improve the quality of our tests. How does these new numbers (from the fully enclosed box) compare to the results from evan9162 or Newbie? Are you willing to pass around a few LEDs, such as the XR-E P4, the XR-E Q5, and the new Rebel 0100, to evan9162 and Newbie? This is not to dis-prove your own results, but instead to allow us other hobbyists to get the most accurate information from the only three persons that are willing to measure the Lumens of the high power LEDs that we use often. This is for more consistent numbers between testers (which inconsistency seems to come from the two variables: color and Vf). Thanks again!
    My numbers compare fairly well to evan9162 and Newbie's numbers. I think my corrected Rebel 100 results were within 2% of evan9162s. Newbie's were somewhat lower, but not horribly so.

    Yes, I would be willing to make some sort of test rig with a few sample LEDs to pass around. This is actually something I've been thinking about doing for a long time. I would include a power supply set to 350 mA (perhaps also with several other current settings) in order to eliminate that variable. The rig would allow a direct comparison of our results. All things considered, I'd say we're all within 10% of each other. However, it would be nice to determine empirically exactly how close our results are.

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