Maybe they really are better than old two bee but with domes on…
But if they are not better or even inferior to old 2B… Owners of this forum, store owners and We need to write serious complaint to CREE.
Heavy burden for Djozz… Djozz is like HKJ… Most trusted men in their field of testing… Respect guys…
But even if they are equal or if they pump more lumens(which is logical since it is bigger one) it can not change the fact that they are ugliest de domed emitter in a planet with lower lux intensity than old one…
XP-G2 S4 2B was not famous as domed emitter; Right? It was famous for it’s dedoming power and maximum lux performance?
And now?… Intensity is equal or lover than r5 bins of first generations of XP-G2’s with g damn Hulk tint.
If the lumen output is the same, a larger reflector (larger diameter and longer to give the same diameter / length ratio) will put those lumens into the same sized spot as the smaller die / reflector combo! I agree that its not really a solution to the problem because you’re losing the form factor to retain performance.
Sure. A larger die that has the same or less output than a smaller die would logically have less surface brightness, resulting in less throw in a given optic, but a larger die that has more output might have the same surface brightness and so should offer the same throw in the same reflector. Surface brightness is key to throw.
I got several emitter packages that came today so decided to arrange my modding stuff, and look what i`ve found: i totaly forgot about those
I have to arrange my flashlight stuff, wonday what i will find in there…they are kinda messy though, working, kids, family…dont have much time to arrange them lately
Cree has done this to us before (XM-L2, anyone?). Cree will do it to us again. We are enthusiasts who are running these LEDs far outside of their ratings, so anything could change for us at any time. Cree rates the XP-G2 at maximum of 1.5A. That's all the guarantee, so when we can only get 3.5A instead of 4.5A on a single battery well, that's our problem. Same goes for the slight die changes and dedomed emitter performance / tint shift.
I’m pretty sure those are not genuine cree LEDs, changing the die size without notice would be PIA for light designers because existing optics for XP-G2 would not give desired beam angles anymore,which means product redesign; it’s hard to believe that any LED manufacturer would do that without special notice on website and in datasheet.
Its a common issue with those big companies, they simply dont give a damn, they can affort it, they are huge
I usualy work with Phillips, Osram est in my work and when we just manage to apply a product in a proiect they just change it without a notice, yet the customer do care
In that case, the emitting angle isnt fixed, the flux isnt fixed too, everything has its” confort for the producer” margins, so i am quite sure its a genuine product
I received the leds from LI. I hope to test them on monday (no guarantees), but already I did a visual comparison with an old batch XP-G2 S4 2B from intl-outdoor with the stereo-microscope tonight, left old XP-G2 S4 2B, right new XP-G2 S4 2B (when mouse-over works again I will insert it):
At least it is clear that the production proces has undergone a change, as LI already showed, and led4power already reported a year ago: the new die seems slightly bigger (dedoming will give exact numbers), the number of dots on the die have increased, the phosfor is rougher (not clear on the picture, very apparent in real life), the tint of the phosfor is a bit more orange with small red bits in it which are absent in the old die. This suggests a warmer tint, and this suggestion gets stronger when the boards are inspected under 365nm light (left old, right new, btw the Noctigon boards are clearly another batch too, a different red paint is used):
But when the leds are lighted up (in series on a led-tester, picture is at ~1mA, but at 50mA the difference is the same), the tint difference is not dramatic, the old led a bit more green, the new led a bit more red, but I would place them at the same colour temperature. If both would be 2B I can not estimate by eye. I have a small colour tester coming in next month that can tell more about that.
I'm curious about any output differences. More about that to come!
I tested the new XP-G2 S4 2B for voltage and output and plotted it against an earlier test of the XP-G2 S4 2B. I followed my usual method. Some remarks:
*these are tests of single leds, mind that results will vary among equally spec'ed leds within the voltage and output bin-classes
*since last XP-G2 S4 2B test my current measuring has changed a bit, the same current reads 0.1A lower now, this is not corrected in the graph
*since last test I cleaned the inside of my integrating sphere, it reads ~1% higher now, this is also not corrected in the graph.
What can be seen:
-If you correct the new numbers to 0.1A higher current and 1% lower output, the old and new led have virtually the same output up to 3A. Above 3A the old led seems to gradually perform better, so the new led seems to have a slightly worse thermal resistance. But it must be said that I did not reflow the leds myself (based on own experiments I use solder quite generously) , both were done by intl-outdoor: a thermal pad with somewhat sparse solder could already account for this difference.
-The voltage is a different story, once again in a new batch the voltage went up: by 0.1V at 1.5A, and 0.2V at 4A. This is of course killing for single li-ion use in flashlights, and this may be the single most important cause of the lower performance reported by LI. There is of course the uncertainty of measuring just one led, it could be a particularly high voltage one.
-At 1.5A, which is the highest current that these leds are officially rated for, the performance of the new batch XP-G2 S4 2B is great, a somewhat higher voltage but I doubt that it falls out of specs with that :-(
I'm not sure if I need to proceed with dedoming and further measurements, the results sofar explain IMO pretty well what is going on with this led...
