SFT40 Emitter - What's so great about it?

Off-topic Chatter
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It’s a flat (domeless) emitter in a goldilocks size for compact flashlights that significantly outperforms anything in its class by a lot.

3V class, low Vf emitter capable of sustaining max output even on half drained li-ion cells

2500+ lumens from 4mm² in a common 5050 (xm-l, xhp50, etc) footprint

Overdriving safety margin that’s not common for emitters with bond wires. Aka robustness.

Smaller details - the symmetry and psuedo-roundness provided by the uncommon bond wire configuration that ‘clip’ the corners of the square die yields cleaner beam profiles (round corona instead of petals) than square or rectangular dies. And while minuscule, a [more] circular die will net more cd through parabolic reflectors vs a rectangle or say for theoretical reasons a star shaped die. The reason for this is as you light emission moves away from dead center, collimation efficiency decreases - aka it becomes out of focus.

TLDR : It’s a robust, high lumen + high throw emitter with good optical properties and is affordable and practical for use in compact flashlights.

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Thanks everyone for all the good info. I didn’t realize that 3V was such an important spec. Which what are some lights that would be good candidates for swapping to the SFT40 emitter?

Does the SFT40 compete directly with the popular OSRAM W1 and W2 emitters?

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3V is particularly relevant here due to its very high output (2600lm or so). Typically, once you get meaningfully above 2000 lumens, emitters are more and more likely to be 6 or 12v or use multiple chips. The only real exception that’s popular is the SBT90.2, but it’s problem is cost and that it requires way more power than most lights can maintain for more than 10s of seconds.

This emitter properly fills the gap between the W2 and 90.2, and is in the same realm when it comes to throw. W2 probably still edges out a win, and definitely it’ll fall short of a W1. On par with a 90.2 at 25A

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as a person, who used couple of sft40 models, incan confirm that is damn good in brightness and throw.

but it has really serious CON - it is crappy greenish.

at least those pair that i tested.

if that is ok for u, u get impressive throw and briggtness

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Another reason so many of us are excited about this, is that unlike the old XML2, the SST40 was near impossible to fully dedome. So after many many years, there is finally a 4mm² LED truly domeless that could meaningfully outpace the original high amp XML2s. Yes, the XP-L HI did a fine job most of the time, but the Vf was high so it was hard to max them out in the real world.

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Would it be of advantage in low-amp 16340-lights lights like Olights S1R*? They used to use XML2 and now, starting with the Baton 3, the SST-40 if I’m not mistaken. Also, the V11R could use a domeless LED.

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Either there are heavy tint variations or I’m not sensitive: The one I have (Sofirn SP33V3) seems to be quite neutral.

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This would do good in multi emitter lights sp36, EC03, maybe the ft02S, and definitely anything with an xhp50.2 3 volt

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I’m thinking Q8 Pro and C8F

Actually, I think its now time for 5050 mcpcb for the LEDIL ANGIE. In the end, something like an 26800 EA01S but a TIR quad.

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Is this single-cell host compatibility series correct?

SFT-40 } Nichia 219C } XML-U2 } SSC-P4

Meaning if I have an old SSC-P4 3.6v flashlight, it could take an SFT-40?

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It looks like Simon has the SFT40 back in stock. Based on sft40 flashlights are relisted again. Looks like he hasn’t updated his led section though.

Also the hype is well deserved! Just put one in my Convoy M1. It has a perfect Hotspot, there is zero Corona. I’m mean ZERO. this led will pull 11+amps with proper mnt fet driver.

M1 SFT40 MNT Fet vs M1 SST40 A6 driver, there is no comparison

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I asked Simon about the SFT40 LED’s he was selling and he said that Luminus wouldn’t let him sell them outside of a torch for some reason

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Can finally chime in since a Convoy S21B with SFT40 has arrived. Without going into technical details (other posters already nicely did this), I was simply looking for a LED that can replace the SST40 and XHP50.2 without too much trouble. I have a few SST40/XHP50.2 flashlights (Astrolux FT03 and EC01) and I just can’t stand the egg beam. The SFT40 is the only easily available emitter that you can just drop in (5050 footprint as mentioned above) and have a clean beam. And now I can say it’s true. It’s very green on low brightness, but becomes a nice clean white beam at full brightness. Massive improvement and a worthy replacement! I’ll be getting some bare LEDs to swap out those SST40/XHP50.2

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I’d rather have Xhp35, don’t understand the hype

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Well, he’s selling them these days (after CN new year that is): https://www.aliexpress.com/item/1005002783273284.html

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Good luck getting those. Last time I checked they are so badly available that even companies like Sofirn stopped selling flashlights with it.

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If 5000k or 5700k hit the streets and look ok I am think of replacing some XM-L2’s with these. Courui D01 would love one!

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Btw, one thing that’s not so great about the SFT40, is that’s not high CRI. Very noticeable if you’re used to high CRI. But that’s ok for a thrower.

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5000k would be appreciated. Especially if there was a mid CRI variant with R9≥10

1 Thank
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I agree. I really like the xhp35 HI gen 1…but those are long discontinued and supplies are drying up quick. Even the 35.2 HI is largely unavailable. Great emitter, but 12 volts needs 4S 0r boost driver.