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

Very interesting results at changing Tj. The setup used here is the same as earlier light flux vs. Tj tests.

At low Tj (10 °C and below) the light flux decreases surprisingly instead of rising, like at most other LEDs at these temperatures. I've been able to reproduce this behavior several times. Also the Vf rises significantly higher at low temperatures than stated in the official datasheet.

From this point of view I cannot recommend this LED for applications, which are used at low temperatures, like outdoor lighting or even flashlight. The lower the temperature is so lower the light flux seems. Unfortunately I cannot go lower than -5 °C Tj...

I have a question, a bug might have slipped into raw data.
Dedomed output rises from 0.8A to 1A by 25.4%.

If used in a flashlight in a cold enviroment. Wouldn’t it heat up like every other flashlight. Doesn’t seem to take long for this led to put out some heat. I would think enclosed outdoor lighting would trap heat in as well. Like with florescent light on my porch when it’s cold it comes on dim at first but after a minute or two it brightens up to full power


I cannot see any unusual values, even if the raw data are shown in diagram:

Here’s Δlm/ΔA vs. A chart.

A bit noisy in general, but the dimple at 0.8A really stands out. Though as I look at it now, it does so partially because both 0.6A and 1A are a bit low.

So that’s probably not an actual error but just measurement noise…

Does Luminus mark the cathode or anode with the dot on the corner?

See Datasheet…

thanx SO much for time spent on this

viele, viele danke fur Seine Werk.

that gave me all info, i wanted to know

seems that one of CONs about LowCRI is not actual now

Sorry i know this is an old thread

Does anyone know what the full codes are for the top bins ?

it doesn’t appear in the datasheet anywhere but they state that an N5 & P2 flux bin exist

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 don’t think anyone has posted a working chemical dedome procedure.
Slicing is the way to go.

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.