I’m not sure a video is helpful or even a possible way to show this. It often occurs between uses of the light. So usually after hours or days of being turned off. I’ll go check the lights they are installed in now and see if/how many have forgotten their group… I’ll PM if there is anything to show. Thanks for your attention to this!
The notable differences between the 2 LED tests is TA's is at 6V while the fonarevka test are done at 12V, plus the fonarevka tests only show low amps which is interesting, but not showing the whole picture. 12V setups are not so common though.
3A is the max rated current for XHP50.2 and 4.8A is the max rated current for XHP70.2 if you choose to wire them for 6V, if you chose to wire them for 12V then it is 1.5A and 2.4A respectively, finally they are just 4 dies which CREE initially blocked user into using them 2S2P or 4S, but now they launched the so called 3V which of course and also be wired 2S2P or 4S should you want so, but technically 6V-12V is one product and 3V is another product.
Bin to Bin, for example XHP50.2 K4 vs XHP70.2 K4 at the same 3A forward current, XHP50.2 is more efficient and it is not even due to lower Vf, which is not lower.
This is the first I’ve heard of the XHP70.2 outputting less than the XHP50.2. It looks like the fonarevka plot is not an actual test but just data from cree for hypothetical P4 binned LEDs?
Are there any actual tests that show the XHP50.2 is brighter/more efficient?
70.2 is more powerful, but not so efficient like 50.2 . Hikelite already calculated, but here: this is official Cree calculator
…and the most efficient is 35.2 aand SBT90 very low eficiency
Using the Cree calculator with the XHP70.2 P2 and the XHP50.2 J4 which is what TA tested, the relative outputs from the two data sources are approximately consistent; XHP70.2 outputs 14-16% more at a given current between 2 and 3A. The difference drops to ~10% for the K2 binned XHP50.2. Considering bins higher than that is not really realistic since they are not available.
I mean no one in their right mind would buy the lowest bin XHP70.2, if you even could, which I don't think you can.
Basically the comparison is comparing the lowest bin XHP70.2 against the highest bin XHP50.2, and concluding the XHP50.2 is more efficient. It's not realistic because no one would make that choice. They would look at the highest bin available for each, then compare.
We know the CREE specs are unrealistic in several respects:
they list bins not available
in a few case they don't list bins that are available
they limit amps, which is fine for a manufacturer, but we at BLF don't follow those limits. I'm stating the obvious here with the BLF proliferation of FET based drivers, or at least an available FET output channel. We've been doing this for many years now.