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

Soldering is the best option but hard to do without getting air bubbles stuck underneath, and also makes upgrading a pain because you can’t just remove two screws and swap MCPBC+led.

Looking forward to see your test results and of course the setup Enderman :slight_smile:

It will be valuable and educational for us all to see different approaches. There are much more lurkers than doers here. I’m sure many will appreciate what we can see and compare than just talks.
+5 to all the doers
+1 to all the speakers
+10 to all the doers that share their findings
–10 to all those ……. (fill the blanks anyone?)

- Clemence

Yeah big thanks to all the doers too. I mean i do quick tests but i would never go the extemes that some do but its interesting to compare and the graphs are useful!

Thermal paste just avoids hotspots. If the surface is nice an there is already a heatspreader in between, the benefit diminishes as a hotspot between spreader and sink is not such a big problem in our application. If the hotspot were directly on the heat source the problem would be real. Luckily the LEDs are soldered to the board.

It surely will not create a difference of LED burning up and LED staying cool.

its still free lumens though, thus I always use thermal paste.

Yeah, some day I plan to get myself the proper gear for doing controlled testing myself.
I already have good voltage, current and lux measurement, I still need an integration sphere though.
Maybe one like this?

I won’t do these kinds of “flashlight-host-like” tests, I actually want to see how well the LEDs can perform in an ideal scenario with the best cooling possible, with controlled ambient temperature, etc etc etc

You can already see from djozz’s tests that with a tiny bit of thermal paste you get hundreds more lumens, just imagine what a decent watercooling setup and liquid metal paste can do :slight_smile:

This is not true, when all else is kept the same, the difference is ~5.4% as seen in a direct comparison test with the only variable being lack of thermal paste and my setup vs his.

This is about the same I noted in my own tests, 3-5% difference with paste properly applied.

I was mistaken though, it is a 7% margin for error not a 14% with Cree LED’s. Although that is only guaranteed within the rated current range, that goes out the window when you are driving them with 2-4X the rated current.

It also does not factor in dishonest sellers mis-marking LED’s causing even larger variances.

I already proved you wrong about this a page ago, go back and look at the your vs djozz’s graphs.

1830 - 1580 = 250 lumens.
250 / 1830 = 13.7% difference, not 5.4%

2) This is a U5 vs V2 bin too, and U5 is TWO bins below V2. Yet the lower bin is hundreds of lumens brighter? lol

3) Then there’s the fact that part of djozz’s LED failed and that’s why the curve shifts down at 6A
If that part of the LED had not failed you can tell that it would be at 1900+ just by looking at the graph.

4) same thing with the XP-G3, his results are hundreds of lumens higher than yours.
Seriously, this is ridiculous, why are you arguing against your own data?

This will be my last response on this matter. It is a long read but If people read this entire post, I think people will have enough data to make up their own minds.

Those tests are not comparable as I showed you before.

The tests that ARE comparable are all that matter. And they show a 5% difference.

The fact is that a U5 XP-L HI making 1900 lumens is simply not possible. It doesn’t line up with a single trusted members real world results. It is up to you to show that those results are valid and comparable. They are not.

If they were representative of the real world results then you would see more then ~1400-1500 lumens out of a XP-L HI V2 (which lines up perfectly with what my results says it should do BTW)

Here are some paper numbers for you.

Compare the results of that xp-l HI test to official Cree specs: http://pct.cree.com/dt/index.html

The XP-L HI U5 should be putting out ~900 lumens at 3A with a 50C temp, yet in the test you are saying is comparable to mine it puts out over 1100 lumens at 3A. A difference of 22% from official cree specs

Even Cree disagrees with your claims.

Now lets compare my results to the official cree specs:

My XP-L HI V2 is reading 1005 lumens at 3A compared to the official cree sheet which says it should be 991 lumens… A difference of 1.4%

If you go run my other tests you will see that they also line up within the margin of error on the LED’s from trusted sources for the most part.

If you factor in the difference from the official cree specs of 22% then you end up with 1900 lumens - 22% =1482 lumens + 46 lumens for the bin difference = 1528 lumens You then have a 7% margin for error on top of this, bringing the number up to a max of 1630 lumens

Now if we run my numbers in the same way we have a 1.4% difference from the spec sheet. 1620 lumens - 1.4% = 1597 with a 7% margin of error bringing the number down to as low as 1485 lumens.

So as you can see the numbers overlap great when you look at the data from an unbiased perspective. The tests are not comparable though as you can obviously tell because there are too many margins of error involved to get results remotely comparable.

The XP-G3 tests tell a similar story, his numbers are 7% high and my numbers are 6% low compared to the official cree specs. So figure that he got a high binned emitter and I got a low binned emitter.

When you factor in these differences in the XP-G3 numbers you end up at 1636 lumens for his XP-G3 test. Mine ends up at 1668 lumens. That is a 1.9% difference between our numbers.

Yet even with those big variances to deal with, when you run all the numbers, you still end up with less then 5% margin of error between our numbers. Way better then either of us thought it would be. The same goes for other tests I have done on the “same” LED’s purchased from different suppliers. Large swings in output, Cree uses the 7% margin of error liberally IMHO and sellers are not always honest about what you are getting.

This is why these tests are not comparable, you can’t compare a single part of the system with these tests, you have to factor in a bunch of different factors and that is not science. With margins of error this large you can make the paper numbers say whatever you want

In the test where we ran the same exact LED from the same reel and the only variation was our setups and thermal paste. The results were 5.4% different This IS comparable as there are virtually no margins of error with the LED itself to factor in.

Just because I don’t put a lot of stock in paper numbers doesn’t mean I don’t use them. I like to do all the math on paper and see what something should do, then I go out and test it in the real world to see if things match up.

After I see what it does in the real world, I toss out the paper numbers and focus on whatever I find to be true in the real world.

Wen I say I ran extensive tests when setting up my test protocol, I ran months worth of tests to get the best numbers I could possibly get that lined up as good as possible to real world results.

If you disagree with the test setup and results that is fine, it is a free country and you are welcome to that opinion.

I on the other hand could not be happier with the results. They line up with the cree data sheets. The line up with real world results and use. They give people a good indication of what they can expect from a given LED in the real world. Exactly what I wanted since this is a flashlight board.

Even a mainstream lighting setup would not run them any cooler then my heat sink setup, cooling costs money and noise, things that lighting manufactures are not willing to sacrifice anymore then they positively must. Generally lighting LED’s run much hotter then I am.

I am starting to understand why Djozz got so burned out running tests though, I don’t see me running too many more with my life getting very busy going forward anyways.

I even tested all of this for you, real world testing shows that the difference between thermal paste and no thermal paste with high clamping force is less then 1% or about 15 lumens. Not even remotely the hundreds of lumens you claimed.

Just how important is thermal paste? The results may surprise some people... Tested by Texas_Ace

This is why I don’t put much weight on paper numbers.

P.S. Djozz and everyone else, please do not take this as in anyway putting down djozz’s tests. As our direct comparison tests show, our setups read very similarly, so I can’t say much anyways.

He puts in a lot of hard work and will hopefully keep doing so. I know I will be using his data going forward anytime I want data for a new LED on the market.


P.P.S. That said Those particular XP-L HI numbers are off for some reason, why I have no idea but I have had tests with numbers that just don’t make sense as well. It just happens. All sorts of possible reasons. It is an old test with his old test setup IIRC so not worth talking about.

So your point is that since there is such large variation, neither your tests nor djozz’s test mean anything because they never represent the real numbers?

Half your post is saying “there is huge variation” and the other half is “they line up with cree datasheets and real world results”, which is it? xD

You also contradicted yourself when saying that the temps were fine and you could “touch the PCB” and at the same time saying the dome is burning off.

At the very least your tests are comparable between eachother… but that’s about it.
The difference between flashlight host size also means that your results are only representing one scenario, A large SR90 sized host provides much better cooling than an S2+ host, which is what your “no-thermal-paste” setup seems to replicate.
Since temperatures aren’t included at each point in the graph then it’s not possible replicate these numbers at all, which is one of the main requirements of the scientific process.
With temperatures, it would be possible to replicate the same scenario because at the same voltage, current and temperature the only variable that you are testing is the bin itself.

If you actually ran months of tests then I would have expected a proper statistical graph with error bars, standard deviation, multiple samples, an error quantization histogram, and die temperatures :confused:

PS - no I don’t believe djozz got a magically good U5 and you got a horrible V2.

Thank you all for doing such LED tests. It is very helpfull and I know it takes much time.

Thanks a ton, TA and djozz, for all the tests you provide, your time and effort.

2019, I am looking to build a new work light with 10 hour runtime. So, 2 cell, 1 to 2 watts max.

Obviously, the buckpuck 700 would have improved runtime, with lower fV over xpl1. Cri improved over v6 4k xpl1.

However, I can make it modular by using the amc7135. The rear cell can be removed, for a single cell edc with typical pathetic runtime short of a day at a work level of lux needed to see extreme detail 2 meters and down. This design allows for safer charging, and ability to have a pwm dimming board on rear battery pack, for easiest, best control of current with dial, like the buckpuck. Hey, I use my lights for work. Runtime is everything.

So, anyone confirmed if the amc7135 will make use of the lower forward voltage for better runtime? Or does it just burn off the excess voltage? I never use cells not rated down to 2.5 volts. My buckpuck cut out just before this. The amc7135 cuts out somewhere above 2.93 V. I can only access 85%rated cell capacity with the amc7135, while I get 100% capacity out of the buckpuck 700.

And yes, I exclusively do white wall inspection. Hoping eye rods are not off kilter by spill tint shift. I see no beam shot indoor yet. Higher cri, with no discernable drop in intensity is the goal, along with increasing runtime.

First off it would seem a simpler option would be to just carry an extra cell but I can understand if this is not possible.

Far as the 7135’s, they burn off excess voltage but as the voltage gets closer to the LED Vf then they will simply be on 100% like an FET giving quite high efficiency actually.

Also, just so you know, you can getting around 95%+ of the cells capacity at 3V, below that there is very little power left in the cell. I forgot the exact numbers but you can look it up. It is not a linear drop in capacity vs voltage.

AMC7135’s just burn off excess voltage. So when using them, the only advantage of a low vF LED is when the battery voltage falls, output will be retained for a while longer.

Overly simplified examples… assuming an AMC7135 voltage drop of ~0.12V:

  • LED with vF of ~3.4V. When the battery is at 4.2V, the 7135 is burning off the extra 0.68V. When the battery drops below 3.52V, it begins to fall out of regulation (that is, the amperage will begin to drop) because the 7135 can no longer supply the voltage needed for both the 7135 (0.12V) and the LED (3.4V).
  • LED with vF of ~3.1V. When the battery is at 4.2V, the 7135 is burning off the extra 0.98V. When the battery drops below 3.22V, it begins to fall out of regulation (that is, the amperage will begin to drop) because the 7135 can no longer supply the voltage needed for both the 7135 (0.12V) and the LED (3.1V).

Buck drivers have their own inefficiencies, but you should see extremely consistent regulation and somewhat better battery life (though probably not a world-shattering difference). Here’s a couple graphs. These are different lights, so ignore the overall lumens and runtime. But note the difference in the consistency of the buck driver vs the effect of falling out of regulation with a AMC7135-based driver:

Click for larger images

EDIT: I see TA beat me to the punch, oh well

maybe but you did a better job of explaining it lol.

Thanks! Answers the runtime question.

I haven’t seen any Xp-l2 beamshots. I am interested in the white wall artifacts, the side by side with the xpl1. I have put up with beam artifacts before with white wall inspection. Some beam artifacts can be mentally corrected for, and others cannot.

For example, I think the xpl hi I built, using a 31mm smo has a purple dab in the spot that is over the top, for what I need. Great throw at 700ma,at Lea, st - good for some work. But I might be fine with a ring around the Hotspot, as long as the 12 degree Hotspot had excellent brightness, uniformity and cri. Most everything in real life is a tradeoff. Just trying to get an idea on the degree of tradeoff I would be committing the light to (with beam, cri, ring artifact, color shift in Corona, slight lumen drop, slight runtime improvement). A few good descriptions here, but want more, and representative ww picts. If it can not be photo captured, is it really that bad?

If you are at all concerned about beam artifacts, the XP-L2 is probably not for you. Try it out for yourself though. I’ve tried several (70 CRI, 80 CRI, 90 CRI, 4000K, 5000K, EasyWhite vs non-EasyWhite) and can’t stand any of them. We’ve seen some low vF LEDs lately (SST-20, SST-40), some with great output and CRI (LH351D), super high CRI (SST-20, Optisolis, E21A), and uniformity (Luxeon V & V2)… but finding an LED will all or most of those attributes? Let me know when you find it!

Me too! I keep searching for that unicorn LED but have not found it yet. The closest I have gotten so far is tint mixing which can fix most of the issues except the tint shift. That needs a diffused optic.

My EDC is still a triple XP-G3 high CRI mixed tint setup for this reason. I simply have not found anything nicer.

Although I recently tried some SST20 LED’s and if I could find the bin I want, I think that could get close, particularly if I tint mixed some high CRI 4000k with a ~5000k to end up close to my ideal 4500k mark.

The XPL HI's, to me, are about the best beam/tint around. I personally prefer the V2 5D's being sold by MtnE and IOS, but I do favor the 4000K neighborhood. The 3500K SST-20's from Blue are also looking very good to me in a ROT66, but XPL HI's in the 5000K range I've seen look good as well.

Similar to TA above, my favorite EDC right now is a modded SWM C20C with a triple of XPL HI U3/U4 2700K 80+ CRI, from MtnE. It's a little on the warm side for me, but I like the cozy/home sort of glow you get from it, a classic look.