LED test / review – Luminus SST-40-W Specialty White N4 BA (+ dedomed) – Here it is, the next gen XM-L2!

From OP: “In dedomed state the SST-40-W is less efficient than a XP-L HI V3.”

The graphs do not appear to show this. The output of the dedomed SST-40 is marginally lower for a given current, but its Vf is much lower, around .5v lower at higher currents. At 6 amps it is using around 3 watts less power but producing almost the same output.

And Luminus has updated the production process of SST-40 since the Koef3 test.
There was one known change - they use tougher bonding wires which increases current carrying capability (SST-40 seems FET-safe with 18650 now). There may have been others.
I haven’t seen a newer test of this LED and I think it would be really useful…

It is my day off so I had some time. I tested the 5000K SST-40 that I retrieved from my Wildtrail D80 V2, on its own Palight 20mm DTP board. So I did not do the reflow myself and trusted on Wildtrail’s reflow. The rest was standard procedure. I did not make a nice comparison graph, but it is easy to get the picture.

So the bond wires blew at just over 9.5A which is not much different from my test 2.5 years ago (link), and from what koef3 found in the OP of this thread.
The voltage curve is almost exact what I found for the led that I tested 2.5 years ago.
Further, I now found a maximum (2300 djozz-lm at 8A, mind that this is a 5000K led as opposed to the 6500K led of the previous SST-40 tests), while the earlier tested SST-40 leds kept increasing output until the bond wires gave in. It can be a bad reflow by Wildtrail, but my feeling is that it is real. In the picture below you can see, apart from the toasted bond wires, that the dot pattern on the phosfor is different from the original SST-40, so Luminus gave the SST-40 quite an overhaul, which may just have influenced overcurrent performance.

I unsoldered the test led and although they did not use an overly large amount of solder (me I’m pretty bad at that :person_facepalming: ), it seemed that the whole thermal pad was covered fine.

Beautiful test! Dot pattern like on old XP/XM emitters.

We need larger emitters with super lux performance.

Thanks a lot djozz!
The results are disappointing…

Thanks, I just received an SST-40 N5 DD Neutral White 5000K from KD, now I need another host to try it in.

This is just one led tested, as always, I may have got a lower performing one, or there was indeed an air gap under the thermal pad.

I have some new die size measurements to report. Based on lumen output and throw measurements in the same light I have supposed that the SST40 die size is larger than the XPL, but I’m not sure there has been a direct comparison done. I used calipers to measure the die size of a dedomed SST40 N4 (6500K earlier gen) and of a dedomed XPL V6. The SST40 is 2.06mm across so 4.23mm^2 and the XPL is 1.93mm across so 3.73mm^2. This is about consistent with my observations: at the same lumen output the SST40 beam intensity was about 10% less.

Djozz, I'm wondering if Luckysun used an older version of the SST40 because I got 2,121 lumens with the Astrolux C8 Copper. OTF lumens should be 20% less than emitter lumens so actual emitter lumens should be about 2,550 lumens.

Astrolux C8 Copper Mode 7 2,121 lumens 6489K -0.0057 DUV 68.1 CRI -11.6 R9 41.9 R12 60 Rf 99 Rg VTC5D
Astrolux C8 Copper Mode 6 1,233 lumens 6489K -0.0060 DUV 67.7 CRI VTC5D
Astrolux C8 Copper Mode 5 609 lumens 6339K -0.0045 DUV 67.8 CRI VTC5D
Astrolux C8 Copper Mode 4 218 lumens 5363K 0.0068 DUV 67.0 CRI VTC5D
Astrolux C8 Copper Mode 3 71 lumens 5151K 0.0105 DUV 66.8 CRI VTC5D
Astrolux C8 Copper Mode 2 11 lumens 5146K 0.0098 DUV 66.6 CRI VTC5D
Astrolux C8 Copper Mode 1 <1 4890K 0.0098 DUV 72.1 CRI VTC5D

Of course: how old is old?, but at least the SST-40 from the D80V2 is a 5000K version and that is not very long on the market, and it shows the alternating dot pattern on the die unlike the oldest SST-40’s that have a square grid dot pattern.

Tell me, please, how to do dedoming this diode? I soaked it in gasoline, but it does not change. I kept it in a boiling nitro solvent, and in acetone, but the silicone dome does not change. It does not become friable and cannot be removed, as the hairs break off.

I tried a few methods and lost many leds but I never got this led to dedome properly, although there have been people who claimed they could.

At one point Kaidomain sold dedomed SST40. Also it’s likely that Simon will soon sell the SFT40, a SST40 without a dome.

I have used magnifying glasses, a fresh razor blade and some washers from the toolbox.

See my sales post where you can see how it looks. (in bed, sleeping....)

I wanted to swap out some of the old XML2 for a light fixture and thought a SST40 would fit. I wonder if it has the same hue shift as XML in this thread?

Now there really is a next gen XM-L2, post PCN 5154.

You mean the XM-L3 ?
Phosphor all over the thing, so probably worse tint shift than the L2.
SST-40 is a better choice i.m.o.

No: the XM-L2 has been quietly updated to a flip-chip structure; koef3 ran a detailed test on this emitter with some impressive results. Output is marginally higher than old XML2 at same drive currents, but the new gen is much more robust, allowing you to push more current through. I would guess that it outperforms the SST40, especially in the tint department. There's also more choice of CCTs.

The XML3 is gonna be garbage, for the exact reason you stated.

Oh, i didn’t know it was a flip chip now.
Must have been somewhere in the past 2 years or so.