I can’t find it back on BLF but someone (JaredM?) recently pointed to this Yinding 5050 led on aliexpress as a potential high performance throw led. It has a die size that is slightly larger than an Osram PM1 die and claims to run at 8A which is definity high performance throw area. And the die is round! :heart_eyes: , which promises beautiful hotspots, from both reflectors and aspheric projection lenses.
Chinese leds are improving fast, so let’s see how this one compares to the established brands (Osram, Cree, Luminus). I bought the 5000K version here, they also sell a 5900-6300K version.
First the uniformity of the die, this is the die at 0.5 mA.
It very nice evenly illuminated with a sharp cutoff at the edge.
The hotspot (on the ceiling) from a smooth X6 reflector, underexposed to see it well on a picture.
It is the roundest, sharpest defined hotspot that I have ever seen from a reflector, a sharp edge with no petals! A round die does make sense in a flashlight. Btw, this is at 50mA, at a normal working current the tint is less green.
The tint, here measured at 2A, in the hotspot of the X6 reflector. Ouch!
Very low CRI and way above the BBL, as others have noticed already this led does look fairly green! But for a thrower led for flashlight use I’m not that bothered, it does provide a sufficiently white illumination that will do the job seeing stuff well in a distance.
The voltage/output test was done like all my more recent emitter tests, for links to my other led tests, see my sig-line below this post. I described the method in detail in my XP-L test, with two minor upgrades since that should not matter significantly for the results: I used my Integrating sphere no. II instead of no. I, and for the current I used a clamp meter, which appears to measure 0.1A lower than the power supply current-reading that I used for my earliest led tests.
Some further remarks about my led tests: 1) just one led was tested which I hope is representative for the whole batch, reflowed on a DTP copper board (XM-KDlight 20mm), 2) I used my large version II integrating sphere with high quality luxmeter, 3) the output numbers and voltages were measured with the led close to ‘steady state’ for each current, so warmed up and settled, you should be able to get these numbers in a well heatsinked flashlight. Mind that these are output numbers of the bare led, in a flashlight there will be losses from light obstructions, lens and optic, 4) output is in ‘djozz-lumen’ defined as 1/550 of the output of my Sunwayman D40A on high setting, which I hope is close to the real lumen, but at least is consistent over all my emitter tests done in integrating spheres. Last year I checked the djozz-lumen with lights measured by maukka and the djozz-lumen seems 7% to 11% high (depending on spectrum) compared to maukka’s calibration.
I added the graphs from three earlier led tests that I thought relevant in the chart, for comparison.
Test data:
In summary, yes this led performs in the same league as the established big manufacturers.
*the voltage graph starts to curve up starting at 12A which is unusual, and indeed after the test-torture (I stopped at 15A, before the led was really dead) when dialing down to 6A, the output is a bit less than on the way up and the voltage has gone up by 0.5V. Sounds like damage occurring when going over 12A (which is well over max, so small deal).
*both voltage and output of the Yingding follows the XP-L Hi U5 quite closely, but the XPL-Hi has 1.8 times the die size so the illuminance of the Yinding is way better (even if this is not the latest output bin of the XP-L hi). What I like about the Yinding voltage curve is that, unlike the modern low voltage leds, it looks very suitable for direct driving it on a single li-ion cell. I can use my favourite BLF-A6 driver again 
*for real comparison as a thrower led we need to add the die sizes to the equation. Recently I did an unscientific measurement of several domeless leds so we can use that:
Now we can calculate the output/die surface area at the maximum output. For the Yinding5050 this is 895 lumen/mm2 while its closest competitor Osram KW CSLPM1-TG makes 835 lumen/mm2. So it is slightly better. The smaller die Osram NM1 still throws a bit better at 950 lumen/mm2, but with less output and smaller hotspot. Other leds in this list: the SFT40 emits 675 lumen/mm2 and the XP-L Hi U5 emits 490 lumen/mm2.
Mind that all calculations here are based on my own led tests of single leds, while leds can vary individually and not everything may be dead-accurate. And my djozz-lumen is known to be a bit high (7-11% compared to maukka’s calibration) so to compare these numbers with other lists you have to compensate for that.
Conclusion
Yes, this chinese led does perform among the best thrower leds currently available, with great output to go with it and a round die for beautiful beams. If you can overcome the quite disastrous tint and CRI that is, but since this is a dedicated thrower led, I find that forgivable.
(At 50mA low current the tint is really really green, duv=+0.0335!)
) I will try them in a bunch of lights. The round die is super cool. Also, the Vf is perfect for true direct drive… My favorite way to run a dedicated thrower.