I think it’s more likely to be a Titanium nitride coating, not brass.
Depends if it oxidises or not. If it does, it can be brass. But brass is usually not used to plate anything except some steel brushes
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In other words, brass has good thermal conductivity. Grade 5 Titanium on the other hand does ~7 W/m K.
In any case, the copper MCPCB transfers the heat to a much larger area than the LED’s thermal pad. Until someone sets up a thermal camera and quantifies the difference in LED thermal junction temperatures when a copper MCPCB is attached to various substrates, speculating about the thermal performance is a fart in the wind.
Something to try: take an LED mounted to a copper MCPCB and attach it to nothing at all. Power it with a benchtop power supply. You might be surprised at how much output it can sustain.
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Finally got around to installing the SFT25-R 6500K into the L21B and I’m a bit disappointed at the range compared to the PM1.
Turn On at 20m with a certified light meter
SFT25-R 6500K: 1,393m
CULPM1 5700K: 1,341m
I expected it to reach a good amount further.
Edit: bezel may not have been tight enough on the SFT25R unit, could have caused lower numbers, will retest.
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Once did an experiment using a S21G copper head with XHP50.3 HI 3000k and a 3A driver.
Copper head on an aluminum body first. 5 min at 35% power. Head went up 8,9 C and tail switch went up 7 C.
Copper head on a titanium body. 5 min at 35% power. Head went up by 14 C and tail cap went up by 0,8C.
Titanium lights are beautiful, but their performance is horrible.
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That’s a 8% increase in intensity, still something!
Your optimization of the centering/focus probably took away some of the advantage of the SFT25R; in stock form the SFT25R will have an additional advantage of better centering/focus due to the easier footprint, a round die, and slightly larger LES.
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Both paired with 8 A driver?
Yes, the 22mm 8A Buck driver. SFT25R had a black spot in the centre, cleaned with IPA after install. Is 8A too high? Datasheet shows 7.5A max, but usually we can overdrive them a bit. I’ve seen others on reddit sharing theirs failing, I just thought that was flux.
Edit: Disregard that burning emitter, bezel wasn’t cranked down enough maybe. I’ll test another emitter and check.
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I have tested SFT25 only in Wurkkos TS12 6500k and Convoy T6 5000k but it is max 5A for Convoy, for TS12 I think about max 3-3.5A. Visually checked TS12 has a little better throw than T6 but T6 give stronger light intensity.
Maybe 8A is too high but that light has good thermal mass and stepdown will save led from failing. It is question if L21B relector and gasket are optimized for SFT25.
I write about problems with my last purchased L21B with round black gasket, uncentered led and dust inside with irregular beam shape and Simon send me new reflector and new black gasket which are little thicker than old and when I change old reflector and gasket with new, situation becomes much better and I get good throw like my old L21B with white square hole gasket, maybe a little better throw. Now I have black donut hole in hotspot on distance smaller than 1.5 metters but on bigger distance beam is very good.
Visualy I don’t see any diferency between new and old reflector, but beams are totaly different.
I think that 1400 meters of throw from SFT 25 is very good result!
Please tell us about hotspot, spill and sidelight differencies between SFT40, SFT25 and Osram.
That looks great.
I wish there would be a scaled up 21700 Version of the T6, it looks so good, but it’s so small…
I could do with a 18650 version. The slightly flared head is very pleasing to my eyes.
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Yes, great idea! Someting with a 40mm head to fill the gap between M21B and M21A.
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Isn’t that more or less the C8+ and M21A?
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Will the multi-cell multi TIR lights get restocked or are they discontinued? I forget the model number, but I’ve been watching for over a month w/ no luck.
S16 is very good flashlight but underated and not very popular?
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Either that or the S11 head diameter @INeedMoreLumens …
I never saw anyone comparing those reflectors
Got it today, Lightmaster says:
I like the light so far. And of course it’s super cheap and you can pump a ton of Amps into this LED - so probably great for budget mods
Edit: And a comparison to the generic LEDs Kaidomain sells:
Closest:
But still different, Chip-size is bigger on the LHP531
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