XP-L2 V5 Output & Death test by Texas_Ace Over 2200 lumens! Still worked after 15 Amps!

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mattjk
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My tests seem to correlate with what is stated in the first post. Ran upto 10amps on a beast of a heatsink and it was getting brighter up until i passed 10a. Great LEDs should have no problem whatsoever direct driving on 4.2v

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Hi Tex, after 10A did the base of the dome lifted/separated from the phosphors?

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clemence wrote:
Hi Tex, after 10A did the base of the dome lifted/separated from the phosphors?

Not at 10A but it did somewhere between ~12A and 15A. Not sure exactly when but my guess is around 13-14A is when it started.

By the time I reached 15A the dome was starting to burn which is part of why the output was reduced.

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My XPL’s dome separated at ~10A. Improper heatsinking I think

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Geez you guys and your crappy heatsinks, gotta step up your game!

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Enderman wrote:
Geez you guys and your crappy heatsinks, gotta step up your game! !https://linustechtips.com/main/uploads/monthly_09_2015/post-4438-0-73633...!

I tried one of those at first but could not drill/tap the copper for anything. I snapped off 4 or 5 drill bits before giving up.

Although the one I use now is just as big but it is an aluminum core rated at 135W and I was able to drill and tap it in order to get a good connection for the mcpcb.

I don’t use thermal paste to help replicate a flashlights thermal path a bit better. Plus I hate cleaning and messing with thermal paste.

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I used big aluminum block (the one in many of my pics) submerged in iced water. The problem seems to be the dirty contact under the already oxidized copper MCPCB. Forgot to clean it
I have a big Pentium 4 heatsink + fan but currently soldered to a 144AR VirEnce board as my work light. At 2A (~25watt) , it’s Ts only ~40-42C @28-30C ambient.

Edit: not Ts, its the heatsink fin temp. The fan rated at 12V but ran at 5V only powered by USB

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Texas_Ace wrote:
I tried one of those at first but could not drill/tap the copper for anything. I snapped off 4 or 5 drill bits before giving up.

Although the one I use now is just as big but it is an aluminum core rated at 135W and I was able to drill and tap it in order to get a good connection for the mcpcb.

I don’t use thermal paste to help replicate a flashlights thermal path a bit better. Plus I hate cleaning and messing with thermal paste.


??? You kidding me?
All high quality flashlights use thermal paste.
Using no thermal paste is HORRIBLE for temps, literally the worst thing you can do before sticking an insulator between the two surfaces.
Even toothpaste works better than no thermal paste.

No wonder your LEDs are dying at 10-15 amps, they are probably running like 100 degrees C higher than the heatsink.
Your 135W heatsink is nearly useless if you don’t use thermal paste.

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Enderman wrote:
Texas_Ace wrote:
I tried one of those at first but could not drill/tap the copper for anything. I snapped off 4 or 5 drill bits before giving up.

Although the one I use now is just as big but it is an aluminum core rated at 135W and I was able to drill and tap it in order to get a good connection for the mcpcb.

I don’t use thermal paste to help replicate a flashlights thermal path a bit better. Plus I hate cleaning and messing with thermal paste.


??? You kidding me?
All high quality flashlights use thermal paste.
Using no thermal paste is HORRIBLE for temps, literally the worst thing you can do before sticking an insulator between the two surfaces.
Even toothpaste works better than no thermal paste.

No wonder your LEDs are dying at 10-15 amps, they are probably running like 100 degrees C higher than the heatsink.
Your 135W heatsink is nearly useless if you don’t use thermal paste.
!http://cdn.overclock.net/1/16/162af502_imageview.gif!

The LED still worked at 15A, the dome just started to burn. Also 15A is an insane amount of power for a 3535 LED to handle, this is the first LED I have ever heard of to do such a feat.

Not running thermal paste is not a big deal. It increases the thermal resistance some but not that much. The point is that flashlights will run way hotter then a big fan cooled heat sink, not running thermal paste helps simulate this.

I ran an extensive battery of tests before settling on a testing protocol.

For example in this test I actually removed the LED and added thermal paste after 10A to give it every advantage as I pushed it towards death. If you look at the lumen graph though you will notice that lumen output is actually WORSE with the arctic silver 5 then with nothing at all. output dips slightly

After that I no longer cared about running thermal paste in these tests. In other tests I saw much the same thing, only very minor changes in lumen output with thermal paste vs none. A less then 3% difference in output is not worth talking about.

Paper numbers are great but real world results > paper.

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Texas_Ace wrote:

Not running thermal paste is not a big deal. It increases the thermal resistance some but not that much. The point is that flashlights will run way hotter then a big fan cooled heat sink, not running thermal paste helps simulate this..

This is 100% not true. It makes a huge difference.
There is a reason why it is absolutely unthinkable to run computers without thermal paste.

I have no idea what you did wrong in your test, because when running an LED cooler it should give more output.
You probably damaged the LED by running it without thermal paste, that’s why the output was worse when you continued after 10A.

Texas_Ace wrote:

In other tests I saw much the same thing, only very minor changes in lumen output with thermal paste vs none. A less then 3% difference in output is not worth talking about.

If you apply the paste correctly and your heatsink actually works, then the curve should begin dropping at much more than 10 amps.
Temperature is what makes the output decrease the more amps you feed it.

And PS the point is not to have tons more output, the point is to prevent the LED from dying, and to extend its lifespan rather than having it degrade 2x faster than necessary.

Texas_Ace wrote:

Paper numbers are great but real world results > paper.

Those are results from real tests.
You can look up any thermal paste benchmarks and you will see how horrible no paste is.
I can’t believe that this isn’t common knowledge in the flashlight world, it’s just ridiculous. In any other electronic or mechanical field everyone knows how important thermal paste is.

You should redo your test properly, using an LED which hasn’t been driven to 10 amps without thermal paste, and use an IR thermometer to monitor the die temperature.
Without thermal paste you will probably see 100 or 150C+ which is why your domes are burning. With proper cooling this will not happen.
Even a small flashlight-sized heatsink with thermal paste will perform better than a 135W heatsink with no paste.

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Don’t be too dramatic Enderman. Unless you’re using extremely rough MCPCB and or heatsink at the mating surface….at our LED level applications thermal paste isn’t that magic.
I always try to lap the mating surface as fine and close as possible to get the largest contact area, so I will need the least amount of any magic paste in between. Thermal paste is just a substitute of air pockets. When your mating surfaces impeded by thermal paste, the result will usually worse than no thermal paste at all. That’s why even though thermal grease/paste have somewhat lower thermal conductivity than premium thermal pad, the grease/paste will always win. Less is better.
I seldom use ultra premium AS or whatever brands those online magazines tested, just simple ultra fine graphite mixed with silicone oil or….oftentimes just my moly-graphite bearing grease. The graphite powder is from Techline when I used to tune race engines back in 2000’s.

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You can say what you want, I tested this a few times in back to back tests when setting up my setup.

The difference between thermal paste and no thermal paste was only a few percent difference in output. The LED was not damaged at the 10A point. I retested it after adding the thermal paste at low current and it still gave the same results as the first test. I know what I am doing.

You have obviously not personally built high powered LED flashlights, so it is pointless for me to continue this discussion.

People know what my experience on the subject is, they can make up their own minds as to what they think of the results.

It is very interesting that if I am “so wrong”, that my test results are within ~5% of Djozz’s tests, who does use thermal paste….. Which is very close to the difference I noted between my paste vs no paste tests…..

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This is BLF, we don’t argue as much as we test.

Back to topic:
Tex, so it should be that my result was abnormal? I don’t have any XPL left at the moment. Will try the CRI 90 XPL2 next time. Mark should have it sooner

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clemence wrote:
Back to topic: Tex, so it should be that my result was abnormal? I don’t have any XPL left at the moment. Will try the CRI 90 XPL2 next time. Mark should have it sooner

Not sure I would say abnormal as we do not have much in the way of tests at that level. Generally the max you get on an FET driver is around 9A, so that is about the most people have used it at regularly.

In my case it lived longer but 10A is pushing the limits for sure. I mean all of the last gen LED’s died at between 6-8A, so it even living to 10A+ is amazing much less it making peak lumens at that point.

Basically it boils down to driving a 3535 LED at 10A is extreme and when running on the edge like that things will happen.

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Texas_Ace wrote:
clemence wrote:
Back to topic: Tex, so it should be that my result was abnormal? I don’t have any XPL left at the moment. Will try the CRI 90 XPL2 next time. Mark should have it sooner

Not sure I would say abnormal as we do not have much in the way of tests at that level. Generally the max you get on an FET driver is around 9A, so that is about the most people have used it at regularly.

In my case it lived longer but 10A is pushing the limits for sure. I mean all of the last gen LED’s died at between 6-8A, so it even living to 10A+ is amazing much less it making peak lumens at that point.

Basically it boils down to driving a 3535 LED at 10A is extreme and when running on the edge like that things will happen.

I was just curious. Yes, it’s extremely extreme. You perhaps do 6+ A more often than me. My most used setup is < 1A. Some goes up to 3A but it’s rare.
It’s good to know this LED is so resilient.

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clemence wrote:
I was just curious. Yes, it’s extremely extreme. You perhaps do 6+ A more often than me. My most used setup is < 1A. Some goes up to 3A but it’s rare. It’s good to know this LED is so resilient.

lol, yeah, my lights tend to be a bit on the extreme side.

Course I use TA drivers in my lights that give me a 2.5A regulated mode along with the turbo.

2.5A is enough for 90% of situations really but it is nice knowing I have 6-9A available if I want it.

Triples and quads @ ~20A are lots of fun or some of my SRK’s 30A+.

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clemence wrote:
Don’t be too dramatic Enderman. Unless you’re using extremely rough MCPCB and or heatsink at the mating surface….at our LED level applications thermal paste isn’t that magic.
I always try to lap the mating surface as fine and close as possible to get the largest contact area, so I will need the least amount of any magic paste in between. Thermal paste is just a substitute of air pockets. When your mating surfaces impeded by thermal paste, the result will usually worse than no thermal paste at all. That’s why even though thermal grease/paste have somewhat lower thermal conductivity than premium thermal pad, the grease/paste will always win. Less is better.
I seldom use ultra premium AS or whatever brands those online magazines tested, just simple ultra fine graphite mixed with silicone oil or….oftentimes just my moly-graphite bearing grease. The graphite powder is from Techline when I used to tune race engines back in 2000’s.

If you look under an electron microscope the air pockets between two metal surfaces are huge even if you lap them.
This is why thermal paste is the difference between working properly and instant overheating in computers. It has been tested literally hundreds of times in all kinds of applications, thermal paste is ALWAYS better than no thermal paste (unless you use bad thermal paste of course)

Texas_Ace wrote:
You can say what you want, I tested this a few times in back to back tests when setting up my setup.

The difference between thermal paste and no thermal paste was only a few percent difference in output. The LED was not damaged at the 10A point. I retested it after adding the thermal paste at low current and it still gave the same results as the first test. I know what I am doing.


A few percent higher output basically means the LED is running much cooler, if you look at the lumen vs temp graphs. Why it was LESS output with thermal paste, I do not understand.

If the LED was not damaged, then the only explanation for the lower output with thermal paste is that you didn’t screw your MCPBC to the heatsink properly.
Also I don’t understand how you’re doing all of these tests without monitoring your temps with a thermometer…
Next time check the temperature delta between the LED and the heatsink with and without thermal paste and you will see for yourself.
What you’re basically doing is completely defeating the purpouse of an MCPCB.

Texas_Ace wrote:

You have obviously not personally built high powered LED flashlights, so it is pointless for me to continue this discussion.

That depends on your definition of a flashlight. Maybe you don’t consider my 1.5Mcd lightcannon a “flashlight”, that’s your opinion.
My opinion is that https://yourlogicalfallacyis.com/ad-hominem

Texas_Ace wrote:

People know what my experience on the subject is, they can make up their own minds as to what they think of the results.
It is very interesting that if I am “so wrong”, that my test results are within ~5% of Djozz’s tests, who does use thermal paste….. Which is very close to the difference I noted between my paste vs no paste tests…..

And guess what? His tests with a LOWER bin get several HUNDRED lumens more than your tests. (for example the XP-L HI test)
I don’t care if that’s 5% or 1% but several hundred lumens is a lot.

Sorry that I completely disagree with your methodology, but people need to understand the big difference that thermal paste makes. Yes LEDs aren’t as expensive or important as computer components, but it does make a big difference (when applied correctly, screwed down with equal pressure, etc etc etc)

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Hi Enderman,

Texas_Ace wrote:
I don’t use thermal paste to help replicate a flashlights thermal path a bit better. Plus I hate cleaning and messing with thermal paste.

He also wrote that in the very beginning somewhere when he started all of his tests. What he does is a real life situation simulations where most of the applications have no big fanned heatsinks. So, it’s very useful to all of us. If he reached, say….1000 lumens then perhaps you can get 1000 ++ lumens in your “appropriate” fanned heatsink test rig.
Most thermal control in LED flashlights are done by stepping down the current at certain time, temp, or LED’s Vf at given current/mode, The latter is the best IMHO.

- Clemence

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clemence wrote:
Hi Enderman,

He also wrote that in the very beginning somewhere when he started all of his tests. What he does is a real life situation simulations where most of the applications have no big fanned heatsinks. So, it’s very useful to all of us. If he reached, say….1000 lumens then perhaps you can get 1000 ++ lumens in your “appropriate” fanned heatsink test rig.
Most thermal control in LED flashlights are done by stepping down the current at certain time, temp, or LED’s Vf at given current/mode, The latter is the best IMHO.

- Clemence


Well without monitoring the LED temperature there is no way to know that this is actually representative of what people are getting in their flashlights.
I often hear numbers from people’s lights that match djozz’s tests, again reinforcing the fact that thermal paste makes a big difference.
This is why all high end flashlights use thermal paste. Even a cheap chinese $20 light I bought randomly has thermal paste, although it was crappy paste.

If the point was to simulate flashlight, then either
A) the temperature should be monitored to match the temperature in a flashlight host
or
B) a heatsink equivalent to a flashlight host should be used, not a heatsink with tons of fins and a fan

I thought the point of his tests was to see how far you could push these LEDs in an optimal scenario, rather than see how soon you can kill an LED with subpar cooling.
Guess I was wrong.

PS removing thermal paste takes a piece of paper towel and a bit of water or alcohol and you can remove it in 15 seconds.

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Enderman wrote:
And guess what? His tests with a LOWER bin get several HUNDRED lumens more than your tests. (for example the XP-L HI test) I don’t care if that’s 5% or 1% but several hundred lumens is a lot.

In all the comparable tests between us (we have talked in PM’s about this as well) my results are consistently ~5% lower then his with naked LED tests, with the different bins factored in.

Which is amazingly close in reality. We were both surprised it was that close.

Once again, real world results > paper results.

Who cares what it says on paper if it doesn’t translate to the real world.

As far as using a thermometer, what makes you think I don’t? I have indeed checked the temp with an IR gun and it was nothing to write home about so I didn’t bother checking it anymore. I can touch the mcpcb during the test, so it is not nearly as hot as you would like to think.

As far as the slightly lower results with the thermal paste, the most likely cause of that is easy, too much thermal paste. I was in a hurry and just dabbed some on without really taking time to thin it out. Too much thermal paste can easily decrease heat transfer. I have seen this several times in flashlights along with all the other big light builders on here.

I used arctic silver 5, so the paste is good. I also screw the mcpcb down tight every time, that was not an issue either. I was surprised at the slight reduction in output myself but it is a perfect example of things not always working in the real world like they do on paper.

I can’t tell you how many times armchair tuners would say that X won’t work due to Y being proven. Only to go out and do X and it work just fine. I learned a lot building and tuning cars. A big thing I learned is that paper numbers just don’t always translate to the real world.

Sure running E85 will virtually always make more power then Gas but running a 3” exhaust will not limit power to 700-800whp as some would have you believe.

I have learned to test it for myself to see what is important and what is not. I mean sloppy mechanics is great because the cars he builds make amazing power and go fast yet they break every “rule” for building a car.

The end point is that the change in lumens measured with or without thermal paste is only a few percent tops. That is all that matters for these tests. No one cares what the temperature of the LED is, only what they can expect to get out of the LED in a flashlight.

Everyone that has built and tested lights with the LED’s I have tested so far has had results in line with my tests. That makes me very happy and is exactly what I wanted out of these tests.

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Little off topic could toothpaste actually be used in a pinch?

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Speed4goal wrote:
Little off topic could toothpaste actually be used in a pinch?

In a serious pinch it could indeed although oil based items tends to work better due to being thinner. Petroleum jelly works fine in many cases.

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Texas_Ace wrote:

In all the comparable tests between us (we have talked in PM’s about this as well) my results are consistently ~5% lower then his with naked LED tests, with the different bins factored in.

Which is amazingly close in reality. We were both surprised it was that close.

Once again, real world results > paper results.

Who cares what it says on paper if it doesn’t translate to the real world.


So 200 lumens / 2000 lumens = 5%??
No, it actually is 10.
Maybe you need a refresher…

btw, U5 is two bins lower than V2, and djozz’s test had part of the LED die at 6A so with better cooling it would be doing 1900+ lumens peak, 300 more than your test.
Oh and in case you didn’t notice, there ARE real tests, not “paper” or whatever you mean by that…

Hey look, again several hundred lumens less:

Do the math, it is a lot more than 5%.

Texas_Ace wrote:

As far as using a thermometer, what makes you think I don’t?

The fact that your dome is burning off and you say “I can touch the MCPCB, its not as hot as you think”

Texas_Ace wrote:

Everyone that has built and tested lights with the LED’s I have tested so far has had results in line with my tests

Really? Because all the flashlights I see that use a XP-L HI are getting about 100 more lumens than your test at 3-4 amps, and I bet if you look for flashlights running at 6+ amps you will see closer to a 200 lumen difference.

Texas_Ace wrote:

learned is that paper numbers just don’t always translate to the real world.

Again, nobody is talking about “paper numbers” here I showed you a real test that proved how bad no thermal paste was, just like every other thermal paste test in the world shows, and for some reason you think your anecdotal evidence is more valid than all these controlled experiments. Unless by “paper numbers” you mean the graphs that you and djozz put out?
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The tests you posted are not directly comparable due to different bins, tints and sources. Although even then if you factor in the Cree binning margin for error into the mix, it is still around 5% for those tests. Don’t forget that each bin can vary by as much as 14%.

I have tested the “same” LED’s on my own sphere purchased at different times from different places and got wildly different results.

Cree builds in a 14% margin for error into each LED bin. So each LED can vary as much as 14% and still be binned the same.

The highest single XP-L HI I have seen reported is around 1400-1500 lumens by many different people. With the new V3 there might be one a bit above 1500 now days. Yet those numbers say that we should be seeing almost 1800 lumens @ 6A with a U5.

Sorry, that just won’t happen in the real world, If it would why does the Astrolux S2 only make about 1300 lumens @ ~6A with a V2 emitter? Interestingly, that is exactly what my test says it should make with reflector and lens losses….

Now don’t get me wrong, Djozz’s tests are great and his latest setup is much improved but these numbers in particular just don’t correlate with real world results. I won’t take a guess as to what caused the high numbers.

The only directly comparable test me and Djozz have publicly posted are the 3rd gen square test where we both tested LED’s from the same reel:


1560 / 1480 = 1.054 Or 5.4% difference in output.

We also compared a few other LED’s via PM and we consistently came up with a ~5% difference.

Put simply the only way to compare these between setups is by testing with the exact same LED’s from the same reel.

We have done this and we have talked about it and ~5% is what the comparable tests came out to.

This is not an issue of weather our tests match up, that doesn’t really matter. What matters is that so far everyone that has built a light using the LED’s in my tests has posted results right in line with the results I got. So thus these tests correlate with the real world results people can expect. Which is the whole point of the tests.

This tells me that my hunch of not running with thermal paste would make the tests more real world accurate for flashlight use was in fact true and a resounding success.

I could not be happier with the outcome.

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Where the heck did you get 14% from? Source?
There would be no point in binning them into 20 lumen increments if they varied by 50+ lumens…

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Enderman wrote:
Where the heck did you get 14% from? Source? There would be no point in binning them into 20 lumen increments if they varied by 50+ lumens…

Each bin is 7% higher then the last. This inherently means that each bin can vary by 7% above and 7% below the rated output. Add that up and you get a total of 14% of error margin between bins.

I have seen every bit of this amount of error when buying the same tint and bin LED from different suppliers or even just different times / reels.

This is why the only comparisons between my tests and djozz that matter are the ones that came from the same reels. Which the Square did and it is 5.4% difference in output.

Since the LED’s were identical that means that our test setups were the only variable. Being 5% off is amazing and more luck then anything to be honest. We both were expecting 10-20%.

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Texas_Ace wrote:

Each bin is 7% higher then the last. This inherently means that each bin can vary by 7% above and 7% below the rated output. Add that up and you get a total of 14% of error margin between bins.

I have seen every bit of this amount of error when buying the same tint and bin LED from different suppliers or even just different times / reels.

This is why the only comparisons between my tests and djozz that matter are the ones that came from the same reels. Which the Square did and it is 5.4% difference in output.

Since the LED’s were identical that means that our test setups were the only variable. Being 5% off is amazing and more luck then anything to be honest. We both were expecting 10-20%.


No…
The bins do not increase by percentage, they increase by 20 lumens.
Bin, min, max
T3 220 240
T4 240 260
T5 260 280
T6 280 300
U2 300 320
U3 320 340
U4 340 360
U5 360 380
U6 380 400
V2 400 420
V3 420 440
V4 440 460
V5 460 480
V6 480 500
W2 500 520
W3 520 540

For T3, 20 lumens / 220 lumens = 10%
For W3, 20 lumens / 520 lumens = 3.8%

The bins are not separated by percentage otherwise the % would be constant.
The number which is constant is the lumen delta.

moridin
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Actually that depends a little on the LED that you consider. I just checked for XP-l and XM-L2. There a bin increase of 1 corresponds to 20 more lumens ( at 85°C and 1050mA). For the XP-G2 an increase of 1 bin corresponds to 8 or 9 more lumen (at 85°C and 350mA). However each datasheets states:
“Cree maintains a tolerance of ±7% on flux and power measurements, ±0.005 on chromaticity (CCx, CCy) measurements and a
tolerance of ±2 on CRI measurements.”

Wieselflinkpro
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You forgot that 20 Lumen difference at binning Current are much more at maximum manufacturer Current, and very more at 10A or 15A.
For exampe with 10 times more current and 7/8 times more Lumenens, there are more difference than 20Lumens between two binnings.

mattjk
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Someone is arguing for the sake of arguing here no names mentioned lol...

Besides thermal paste is for pussies real men solder to pill Wink

 

10a is about the limit for these which is amazing really considering the size the light output is immense i am suprised the bond wires didnt melt before the dome started lifting. My power supply only goes to 10a so i couldnt finish the job unfortunately 

 

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