Thanks guys! For my Cometa, I’m excited to use what I have at the moment which is a SFT40 from Simon. The Cometa doesn’t get much use despite it being awesome even with the 3B XP-L HI. I guess I’m trying to preserve that lens from accidents.
I also have an L2 with an Mtn Electronics FET+1, Crescendo driver with an SFT40 and it hasn’t had an issue being overdriven but I’ll be more careful with the batteries I use in it.
I have Convoy’s SST40 5000K, which is extremely green despite being DA tint bin. Hope to see colour tests of the SFT40 5000K soon.
I think I can make a test of the SFT 40 6500 K soon (with emitters bought by Mouser, not a ‘special bin’ like from KD)
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General-binned SFT40 is usually pretty ugly (and very cool), the 5000k tint bins are particularly interesting because of their scarcity.
Also it seems like warm and neutral high-cri SFT40 is going to be available later this year, it would be very interesting to see if they can stand up to high current or not.
I’ve had some pretty green 6500k, so worst case, all things being equal (green) I think I’d prefer the 5000k. I think minus green would work better on 5000k. Green, green, green- word of the day.
With Luminus emitters the only real solution I think. (From full emitter swap aside.)
The general-binned SFT40 like mine from Mouser are most likely used in flashlights. Don’t think that Wurkkos, Thrunite and co. will buy special color binned emitters from wholesale or directly from Luminus.
My SFT40 from Convoy/Simon has identical tint (at proportional drive levels) to the Osram CSLNM, which is excellent for a sub-70CRI emitter. It’s in 6500K; I’ve heard green things about the 5700K variant that was previous offered. I don’t feel so optimistic about the 5000K version, but a pleasant surprise is always welcome.
Do you know from what color binning this SFT40 is, or is it just luck to get a good tint in a Convoy pre-build light?
I bought it as a standalone emitter at this link.
I don’t know exactly what the binning is–the description says N5-CE-VJ which is the greenest bin toward the upper end of 5700K, but that description is for a previous variant he offered; his new emitters are cooler and much less green. Pretty sure I’ve asked about binning in the past but AliExpress lost all of my older messages.
I missed one point, is the crystal on top covered, in addition to the phosphor, with some other protective layer, silicone or glass, or is the phosphor open and very delicate?
I’ve broken a SFT40 phosphor with a q-tip while wiping it with alcohol so my impression is that it’s sorta delicate.
I was applying some force in an attempt to clean a dark spot off.
I’ve always been kind of curious about this LED. This test clearly shows that at around 9A, It’s putting out 2600 lm. Which is amazing for a 3 V LED. But most lights in the market seem to be only getting 1500 lm out of that. At the same drive level. Hank is pushing these with a 9a linear driver and getting 1800L. I wonder why
Chances are that the driver isn’t actually delivering 9A to the emitter–there is resistance everywhere in the circuit from wires to contacts. And then one has to account for losses through optical systems.
Oh I get that. But over 30%? That’s a lot. I have an xhp50.3 hi light that’s putting out about what a test on here showed. But this threads test shows the sft-40 as being some kind of super emitter. I had no idea it produced so much output yet I’ve never seen a light clear 2000L with it
Do not take everone’s word for what light output they claim, you can take most lumen claims around with a grain of salt, 20/30% off is really common. That is because measuring light output (lumens) accurately is not trivial , it is hard, lots of parameters need controlled very tightly and people do not realise that.
With a simple home-made contraption and some flashlights with manufacturer-listed output people get ballpark numbers within 20/30%, several people on BLF have made that and it is really what most people, even hobbyists, are happy with. Some BLF-members I trust to be a bit more accurate because they have checked calibration light sources, they may be within 15% (i.e. me, and I know Marco from 1lumen has checked light sources too, and some others)
But to get within that last 5% accuracy is either very expensive (for many thousands of dollars you buy an official integrating sphere plus spectrometer and calibration light sources, and learn how to operate the setup correctly, BLF-member maukka did that) or if you brew a device yourself which is surprisingly difficult to get accurate, you need a very controlled setup (directionally insensitive light collecting geometry, spectrally neutral reflectivities, spectrally correct luxmeters, correctly calibrated light sources) that almost no-one manages to get really right (that official setup is expensive for a reason). People often think they did a good job but end up with 20% variation from the real output easily, because of a flawed setup/wrong operation/dubious calibration sources.
I also do not not think that Hank (Emisar/Noctigon) or Simon (Convoy) have very exact lumen measurents. Maybe Sofirn.
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I understand that some setups aren’t the most accurate. But even with ceiling bounce app and a paper lined box, I get repeatable results that match official numbers and I cross reference 1Lumen, zero air, and grizz numbers and they close enough. My numbers for a 519a match your test of that emitter after counting light loss from reflector and lens. Same with koef3s test of the xhp 50.3. The only thing that doesn’t match is your test of this led and all the lights that use it. Not saying your test is in any way wrong. It’s just showing significantly higher numbers than resistance losses and light losses can explain. Even fet driven lights seem to have a hard time breaking 2000L
Edit. I think it’s the high vf that’s causing the “problems”. Looks to be about 3.8v at high current. A single lithium ion is going to have a hard time doing that at 8+A. But you’re using a power supply. Ok so this guy really needs a beefy buck driver to really make it sing. Not complaining that 2000L isn’t a lot because that is a ton of output
Beefy buck driver + beefy battery + beefy or bypassed springs + beefy wires going to the LED PCB, to get that peak output. With a power supply you can always subtract the voltage drop across the wires and crank up the voltage. Best case scenario is to have a 2S buck driver, but that’s too much effort to get 300 more lumens out of this poor thing.
I do not check the voltage coming from the power supply during my led tests, the voltage is measured very close to the led itself, just 30mm of thick wire and a short piece of PCB trace between the voltage clamp and the led itself. The PS-voltage will be higher.
I believe that a well beefed-up flashlight (as said: bypassed springs, driver with thick traces, short thick led-wires, ) adds very little voltage loss between battery and led, but light loss is a different story: I have done some measurements in the past of added light losses inside a flashlight compared to bare leds and it is quite a lot, in the measured example it is 17% ( Light loss in a S2+ triple mod, added similar data for a reflector light in post#8, added data in post#20 ).
I agree that Luminus may have altered the voltage of their SFT40 leds in later batches. No promises, but I have bought some 3000K SFT40 leds from Simon last week and I may do a quick led test on one of those. For the voltage 3000K 95CRI or 6000K 70CRI should not matter.
Agreed. That’s only worth it for the SBT90.2. I am perfectly happy with an SFT 40 at a measured 1700 lm