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

Ok, this is the first official release of an LED test from my setup. I have a few others already complete that I will be releasing as I get the time to make the charts all pretty and ready for upload.

Cliff notes version

- My sphere and setup is finally calibrated to a level that I feel good about releasing numbers from

- I figured out how to turn a PVC sphere into a true integrating sphere that reads the lumen value directly on the lux meter so no math is involved

- The lumen readings line up perfectly with the Cree data sheet confirming that the readings are indeed accurate

- The XP-L2 is a tank of an LED, handling up to 10A without any damage and over 15A with damage but still working!

  • Over 2200 lumens (2450 peak from cold start) from a 3V single die LED in a 3535 footprint, that is over 40w of power through a single LED! It handled 70W at peak while still working!

First off thanks to djburkes for donating the LED’s! If anyone else has a new LED that you think would be worth putting through the ringer, let me know.

So I will start off by giving a quick rundown of my setup. I have 2 spheres actually, the Josh BLF “standard” sphere and a PVC sphere I made using the stuff I learned from Joshes sphere. Long story short, I have been dialing it in for the last few months to get it as accurate as possible, I am quite happy with the current setup. It is FAR FAR better then the plain jane PVC setup I started out with.

If people would like to see what I did to my sphere, let me know and I might be talked into making a thread on it, the biggest difference is that it is a true integrating sphere and doesn’t allow any light to escape. It also reads the lumen readings out directly on my lux meter, no calculator needed!

Now that it is setup to my satisfaction I can start releasing numbers from it as I will not be changing it any more. Thus my numbers will remain comparable. They are also pretty accurate if I do say so myself, this test for example lines up perfectly with the Cree data sheet.

For the test itself I have the LED’s all reflowed to DTP copper stars unless otherwise noted, they are then mounted on a PC heat sink with fan that I setup to hold said stars. The fan is running the whole time.

I then start the test and work my way up in current using my DPS5015 to power it. I stop every .25A to take a voltage, current and lumen reading.

The voltage drop over the wires is calculated out in the corrected voltage column, thus giving the actual forward voltage (although remember in a flashlight that resistance will not be subtracted).

Now to the test itself!

Ok, so djburkes sent me 2 XP-L2’s to test. I have to say I was not expecting much from them to start but I am VERY impressed with the results! These things are TANKS! I took this guy all the way up to 15 amps and it still worked! Although it was hurt pretty bad at that point.

The test really went great up to around 10A (A whopping 40W), the LED was not even hurt up to this point as I retested it at 1A and it had only lost 1 lumen!

After that it started getting stressed, by 12A it had been hurt a bit and after 13A the tint started turning a bit blue. Somewhere around 14A it started burning the dome, it literally cooked the dome off but even at 15A it was still kicking! I left it there for a little while as well. An astounding 70W of power was passing through it!

The spikes in the graph are when I retested from a cold start to show what would happen in a well cooled flashlight over the first 30 seconds or so. I generally try to time this around peak output.

I plan to install the second LED in a Convoy S2+ tomorrow and see what kind of results it gets there but I was too excited and had to post this test now.

So enough with the talk, time for data!

Click images for larger versions that are easier to read! Or download and zoom in all you want.

I am quoting a post from later in the thread where I put the second LED in a S2+ to see what it did in the real world:

EDIT 1-16-17

I tested an XP-L V5 as a comparison and the results were interesting. Keep in mind the lower Vf of the XP-L2. When compared by wattage the XP-L2 is slightly ahead of the XP-L the entire time. AKA, the XP-L2 is more efficient overall.

Also in the real world the lower Vf means we get much better numbers from the XP-L2 then the XP-L since we can pull much higher currents.

If anyone has any comments on the layout of the charts, the data in them or anything else please do speak up. I would like to standardize my test layout now before I release anymore so that they are all easily comparable.

Holy crap

What if you liquid cooled them when doing testing to keep temps below 50C?
Do you think you would get more amps through it before the output starts decreasing?

Thanks for testing. Interesting info, but what’s more interesting is your pvc sphere! It sounds like a winner. How much did it all cost to build? And would it still the same amount of time to get another sphere up and calibrated since you have experience now?

Do you have a set of standard XP-L data to overlay with?

If you mean like liquid nitrogen then yes, it would do a lot better :wink:

If you mean like the normal PC style setup liquid cooling, it would improve things a little but much like PC’s the cooling is still limited to the ambient air and as such liquid cooling would not drop temps all that much once the internal fluid was heat saturated.

I could actually improve cooling on this setup more then it is now but I did not was the results to be too far off from what we can expect in a flashlight for at least the first 30 seconds. It is already cooled way better then a flashlight, more would simply further remove it from what we would see in the real world.

In the end with improved cooling I think it could make another ~100 lumens but we are reaching the limits of how fast the 3535 footprint and copper star can transfer the heat away from the die more then the heat sink itself.

If this was in a 5050 footprint I am guessing it would make a reasonable amount more lumens all else being the same.

I am quite happy with how the sphere turned out. I have not wanted to really post about it till Josh finished with his GB on his spheres. They are nice spheres, just not really suited to the power of flashlights I deal with on a regular basis. It is also many times the size and it was hard to fit it on the desk.

The ideas I got from it through are the only reason I was able to build mine, I blatantly stole the ideas from him. They work.

As far as cost, it is normal PVC P trap sphere with a few 3D printed parts, total cost was around $35 and a lot of time dialing it in, excluding the meter (cheap H1010A that works great, I have 2 of them and they both read exactly the same, purchased 6 months apart from completely different suppliers).

I suppose I could build more of them, they would not be very cheap due to shipping and time involved with calibrating them. Although I suppose I could try an idea I have had to “standardize” the 3D printed parts and it is possible that it would be consistent enough for what we do.

If people really want to see it I will snap some pictures and make a thread now that Joshes GB is done and he is going open source I feel ok doing it.

I don’t have any XP-L’s out of lights with “trustworthy” suppliers with which to compare right now. Actually I might have one from Convoy come to think of it, I will have to check.

I don’t want to test some random XP-L and let an unknown bin skew the results. Sadly I don’t have many LED’s with known bins left in my spare parts.

Although all my “unofficial” tests thus far have been spot on the cree data sheets.

If anyone has some spare known bin emitters that I could use to get some “baseline” results for my setup for comparison sake let me know.

Where can these be purchased?

The ones that were donated to me were originally purchased from Mouser. They are only V5 bin though, there should be V6 and even W2’s floating around before long (although W2 could be awhile).

I am very interested to see how the other one looks in a light.

Nice work! The charts look good to me.

Let's hear more about that sphere.


I want some !

Nice bit of testing TA :+1:
I like the rows with numbers too, in this case showing this XP-L2 will still do 100LM per Watt at 15½ Watts, at just over 3½ Volts !

Very nice work…I was hoping it was something that I was doing wrong because I really didn’t want these to fail. I’m going to say it was the product of a bad reflow on my part…you live and you learn.

Those are some freakin’ awesome LED’s! Nice tests suite as well. Gotta see the sphere as well.

I think it would be awesome if you started another thread for your pvc sphere. I also have Josh’s sphere but I wouldn’t mind having another. Doing calculations and the off wall can be troublesome if your just in a hurry. And 80% of my lights don’t fit the opening and is too powerful too many lumens.

Cool, thanks. Regarding the graphs, would it be possible to enlarge or bolden the numbers ever so slightly?

Hi TA, about your set-up,

1) you may want to check for integration quality of the device.

If that is not good, your calibration will only work for emitters with comparable emission profile. For example, a flashlight that uses optics to make a radical different beam from a bare led, will read different from a bare led. Every type of emission pattern will require its own calibration.

If integration is good however, it does not matter what type of light source you measure, a fixed calibration is inherent to the design.

The easiest way to check integration is using a small zoomie in spot modus on low setting (actually the goal is a constant output, and flashlights are more constant on low settings, best is a constant current setting, like the lower settings on the BLF-A6 driver that uses an 7135, same for an old-school AK-47 or similar). Shine it into your device at various angles and record the reading. My sphere gives a maximal variation of 3% for any angle that the zoomie is pointed in. See here.

2) you may want to check for the influence that the to-be-measured lightsource in the entrance hole has on the calibration.

Unfortunately, with better integration, this influence increases. Your lightsource is part of the inner surface of the device where photons bounce around. In a well integrating device, photons will bounce around multiple times before being absorbed somewhere, so the photons have multiple chances to ‘meet’ the entrance hole. The entrance hole is a photon ‘leak’ which is is no problem at all because it is accounted for in your multiplier. However, if this leak is not constant (i.e. a shiny bezel shines light back into the sphere, while a black bezel absorbs the light) your multiplier will be influenced by that.

There is two ways to deal with that. Either you can accept this variation in which case you want to have an idea which order of magnitude this error is, or you are going to measure what the error is for each light source and correct the multiplier for that. you then need a build-in constant light source in your device for measuring the correction.

In my big 46cm sphere with 30mm entrance hole, that I use for emitter measurements, I find that entrance hole effects are minimal, I have a fixed multiplier for all emitter tests. For bigger flashlights I open up the hole to 80mm, in which case I do have to correct for the lightsource, if I do not do that, the error can be up to a few percent.

In my small 16cm sphere I need to compensate for the different reflectivities of what is in the 40mm hole every time, the error would be too large for my standard if I do not do that.

Xp-l2, maybe you are not for thrower, but you are a little monster

I really like the addition of wattage column! Not every LED has same Vf to begin with. Wattage is a better parameter to define an LED performance. Great job Tex.

- Clemence