im not sure why Djozz is rating the 351D with such low output. If you look at Texas_Ace tests it pulls way higher. If you subtract like 22-25% from his numbers to account for 4000K and 90CRI you will probably be close to your estimated output.
I would guess ~1200-1250lm Samsung and ~1650lm Luxeon V? Both will look way better than the XPL2 with SMO reflector. Not much tint shift in corona. They wont be “rosy” like a Nichia 90CRI but shouldn’t be green either (this is personal preference, I guess some people like that pink color)
You are right contactcr, I substracted too much to account for high CRI, a few years ago it used to be close to 40, but I looked up the specific bins for these Samsung leds and from the 5000K 70 CRI (W2 bin) to 4000K 90 CRI (S2 bin) you loose just 18. So starting with TA’s numbers, at 4.7A you still have 1435 lm leftover, in a flashlight OTF that should be just under 1200 lumen, compared to well over 1400 lumen for the Luxeon V.
So the Samsung will be 200-400lm less output but CRI90 vs CRI70.
Hmmm tough decision, I only have one CRI90 light but it’s 5700K (Nichia 219) even though it a nice pure white it’s still a bit cooler than I’d prefer.
I’d maybe try the Samsung but I suppose I’d need to buy 10pcs ($22.05) and I don’t do the reflow so I’d have to learn that too. Luxeon V already on the L4P 16mm board, $9.36 for 1pcs. on the board (or $14.42 for 2pcs.)
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It sounds like both these LEDs are better than any 4000K Cree LEDs, I suppose i should just get both and compare them and learn to reflow, then I can upgrade many lights to Hi CRI.
If I read everything correct these are the footprints?:
Luxeon V……………….4040 (XML is 5050)
Samsung LH315………3535 (same as XPL)
Reflowing is seriously easy. If you have 63/37 leaded solder you cant get it wrong. I use an old pan i dont cook on and its super easy to tell when the solder flows.
XPL-HI 4k is nice for a cree offering. Not high CRI but good beam and tint. I still like the V better but both have their uses. Especially since the V has a unique footprint
The thermal interface is very good just like Lumileds claims. Here’s a thermal video which shows that the temperature difference between the emitter and MCPCB is very small. You can barely see any difference in color.
Current increases from 0 to 5 amps in 200mA increments every 5 seconds.
Difference between emitter and MCPCB
Also Fv up to 5A created during the automated test.
Not being a CRI connaisseur (well, I’m not connaisseur of any thing really :D) I do have to say that I have only 2 lights with this LED installed. I must say that all the nights I use them at home and I never thought the CRI was only 70
The beam, tint and the colour rendition of this led is super, even not being 90+ CRI!
Soon I will get more from led4power and I will not regret that!
You should take into account that most of the output is in the hotspot. The average is therefore still above the BBL.
Here’s a measurement with a Convoy diffuser for a very effective averaging (but not necessarily perfectly neutral as can be determined from the CCT change) and d-c-fix:
Duv value tells the distance from BBL. Still above in both.
Thank you for this and your other very informative test results. I hope to someday understand much of your reports.
Here is what may be a very dumb question. One of my favorite aspects of this emitter is how it picks up reds (my personal experience). I, however, do poorly in tests where I have to sort colors. So I don't put much stock in my experience. Anyway, my question is: Doesn't the -32 R9 mean the emitter has poor color rendition when it comes to reds?
Depending on the answer, can someone please help me reconcile my experience with the test results?
The R9 value of –32 means that compared to a reference blackbody radiator at the same color temperature the spectral intensity in the deep red wavelengths (above about 640nm) is very small. This results in duller red colors, but that doesn’t necessarily mean that the reds are anywhere close to invisible or grey.
Thanks maukka. Seems I need to get out tonight and do some side by side comparisons to help me reassess what I think I'm seeing. I'm thinking the tint is what caused me to assume I was seeing reds better.
It very well might be idk never damaged a led doing that way. That’s the way old lumens told me to do it. Instead of exposing the led long exposure to hundreds of degrees the solder melts and is cooled to the touch in 20 seconds
All the datasheets spend like 2 pages going over the proper temp and time to do it so i assume there is something to it. You might have damaged one just not enough to make it not work
Lol very true. I have no way of measuring output. Only current draw at the tail or led I’ve used my iron a couple of times. But takes to long for me. I’m sure there is something to it.
Super efficient!
It would be interesting to see at what current the efficiency peak happens. Every LED has such a peak. Sometimes very small LED actually have a better maximum efficiency compared to larger ones .
