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.

Enderman wrote:

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?

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

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.

blueb8llz wrote:

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?

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.

freeme wrote:

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

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.

LightRider wrote:

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.

RotorHead64 wrote:

Nice work! The charts look good to me.

Let’s hear more about that sphere.

Thanks, I will see about making a thread for the sphere in the coming weeks.

Jerommel wrote:

Nice bit of testing TA 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 !

Yeah, I liked this setup, it was how I had it setup in Excel and figured a screen shot of the whole thing could work well.

I am thinking about adding some more numbers that will extrapolate the readings out for higher/lower bins based on the data sheet specs of 7% per bin. Anyone seen an example where this doesn’t hold true in the real world?

djburkes wrote:

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.

Look at the bright side, we now have a nice test to show what they can do!

mattlward wrote:

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

Thanks, I am very impressed with the output, hope to build a light with the other one to see how the beam looks later.

blueb8llz wrote:

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.

Yeah, if people keep asking I will just have to get off my butt and do it. I didn’t think there would be a lot of interest with so many threads already floating around on how to make a sphere.

CRX wrote:

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

Hmm, have you clicked the impages to view them full size? You might have to click them again after they come up full screen to zoom in all the way depending on your screen size. On my screen anyways the numbers are readable if zoomed into full size.

I can try to make them a bit larger if needed though.

mrheosuper wrote:

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

Indeed they are! Now to find some 90+ CRI versions or even some higher bin versions, ~2500 lumens should be possible with a W2 bin.

clemence wrote:

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

Thanks, I figured it would not hurt to toss those in since they are just a matter of simple math.

Enderman wrote:

True, but I always like using overkill cooling solutions so it’s not like my flashlights will perform like regular flashlights Liquid cooling would still be able to keep temps lower than 85C when the LED is producing nearly 100W of heat or more. You can get a lot lower with phase change though, sub-0 cooling for an LED

Liquid cooling in the classic computer sense is mostly about space savings then actual cooling ability. I for example have always used air cooled setups in my overclocked computers and while it can be very hard to fit the heat sinks the final temps are only slightly higher then those using water cooling with the same setups.

Same with a turbo cars intercooler. after the system is heat soaks all the matters is how fast it can transfer heat to the ambient air. This is determined but surface area and ambient temperature more then anything else. In most cases the air cooler actually has the advantage in surface area (unless using a massive waterblock) and this makes up for some of being inside the computer where the ambient temps are higher.

The Miller wrote:

Nice tests! Yeah please make a (pic heavy ) topic on that tube!

KawiBoy1428 wrote:

What he said!

lol, well if people really want to see it then I guess the people must be appeased. I will see if I can find the time in the next few weeks.

djozz wrote:

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.

All good points.

1: Yes, this was my biggest issue with the “normal” PVC setup, where you put the light would change the reading drastically and that was unacceptable for me. Thats why I set out to improve it and it is now truly integrating as good as the josh sphere anyways. It doesn’t matter where I point the light inside the sphere the readings only change by ~3-4% tops.

Although I have centering rings 3D printed that ensure the light is always in the same place and this means that the readings are even more stable in real world use, the depth that the light is inserted into the sphere plays a FAR larger role then where it is pointed. That can effect the readings by 10% or more easily.

2: This is an almost non-issue for me as I have 3D printed up a wide selection of “centering rings” based on the design that josh uses. These do several things at once. First they are perfectly sized to the head of the flashlight I am testing, allowing no light to escape. Second since they are covered in reflective foil that all act like a large reflector so the reflector in the light itself has minimal effects.

The light also bounces around a lot before reaching the meter so it helps balance out small variations. Now lights that have a thick black bezel do effect things a bit but there is nothing that can be done there.

djozz wrote:

smart to cover the inserts with reflective foil, it was one of my objections to Josh’s sphere that he used inserts that alter the reflectivity of the sphere, in your case I agree that it will create a fairly constant large reflector for any (edit: reflector- )flashlight.

Looking forward to your thread!

I think josh changed his design to include the reflective tape based on you if I had to guess. My sphere showed up with the reflective tape when I got it and it is where I got the idea to use it on the PVC version.

The change combined with the rings made a massive difference in consistency. The other big change was the internal baffle. Although that is a bit hard to explain here although it is quite simple really and works amazing.

will34 wrote:

Thanks for the tests! Looks very promising…

About the improving the chart, I do have a few small suggestions:
-Place lumen on the primary axis and Vf on the secondary for easier reading
-Reduce Vf axis range to 0-5V, and remove the unused decimals for current and vf
-Bigger font, adding axis titles optional

After this you’ll have a very nice chart that you can use for future tests, and adding more lines just requires a few clicks.

1: I swapped the axis’s because most people are more interested in the high end range of the lumen curve vs the low end. This makes the high end easier to read I figured. The right side axis is what all the guidelines are based off of. If people would prefer the lumen axis on the left side that is easy to swap.

2: I increased the Vf range so as to move the VF line away from the lumen line. It was confusing when they were overlayed in the same range although that was before I added the colors. I could knock the VF down some to put it more in the center of the chart if people think that would be easier to read.

3: Which font are you referring to? I should add axis titles, I forgot to do that.