With a DMM and/or clamp meter?

Wellp, some sort of voltage source is still required, one at least capable of our desired emitter current output and input, with enough voltage headroom for wire and contact voltage drops. A standard 5V 5A power supply may do, or maybe some sort of battery holder gizmo with 2S cells in a low state of charge and some :-) long wires. Heatsinking the driver inside an S2+ pill is a good idea just in case we do not have full input voltage control. If we use a multimeter for current measurement place it somewhere in the circuit, maybe with alligator clamps between spring and voltage source. If clamp meter place it around some connecting wire.

Android's ElectroDroid application has a handy voltage drop calculator where you can set wire lenght, gauge, current, etc.

Cheers ^:)

Osram 1mm2 and 2mm2 (bottom) vs shaved xp-l and xm-l2 and xhp35hi

:wink: just to compare the emitting area

Maxtoch M2 Archer with new Osram 2mm

1100m to the church.

180 kCd measured form 3m, from further distance should be more.

Is the corona now oval instead of circular?

So if the the oem specs are to be believed for the Archer M2 (600m beam distance = 90kcd), you have AT LEAST doubled the candela.
The Archer M1 uses a de-domed SST-40 and oem specs are 800m / 160kcd so compared to that the results are a little less impressive.
Can I assume the Archer uses some sort of FET / direct current driver and you are still using it? What battery are you using? Can you take tail cap current measurements?


I did some measurements on 3 of the best 2mm^2 LEDs, the dedomed XPG2 (new style), close sliced SST20, and white flat 2mm^2. The white flat is from Mouser and the item has a range of possible bins so I don’t know the exact bin. I measured the output by measuring the lux directly above the LED (80cm away) and assuming the light emitting surface is a Lambertian surface, which is a good approximation. See here some more information about this method. I use a Tondaj LX-1010B lux meter. The lumen numbers are approximately close to others’ measurements, but assume the usual 10-20% possible error.

I then measured the beam intensity of each LED in an EE X6 head powered by a constant current power supply. dedomed XPG2: 95.2kcd at 4.5A, sliced SST20: 92kcd at 4A, white flat: 111kcd at 6A. I calculated the luminance by dividing by the reflector area of 620mm^2 and assuming 90% reflector and glass efficiency. Then I scaled the output graphs according to this information and the luminance vs current is displayed below.

The white flat and dedomed XPG2 curves have close to the same relationship in the output and luminance graphs, which is expected since their dies have very similar areas. But the sliced SST20 luminance curve is high compared to its position in the output graph. I think this is explained by a non-uniform luminance across the SST20 die. The SST20 has a close slice, but obviously some silicone remains on the die, as pictured here. Near the edges of the die light can reflect off the silicone/air interface and exit the die to the side. This light doesn’t contribute to the light coming directly from the die; it bounces to the side and a higher fraction of it gets absorbed or emits to the side where it isn’t useful. You can see by looking at the lit die that the edges are less bright than the center, pictured below.

The other LED dies are much more uniform in brightness over their surfaces. I think this is the reason for the SST20 having a lower output than the other LEDs. But the measured luminance is high, even higher than the other LEDs for most of the curve. This is because measuring the luminance by measuring the beam center intensity from a reflector only measures the LED die-center luminance.

These 3 LEDs perform relatively close to one another at a given current, but in real world use there are big differences. The dedomed XPG2 still performs well, but the high forward voltage means the current can be low, especially in a mulit-emitter light. The SST20 improves upon the XPG2 in this aspect with its lower voltage, but dedoming difficulties hold it back. The domeless white flat with its very low voltage and higher max output is the clear winner in some applications (multi-emitter), but driving a single emitter optimally might be more difficult.

What about the Nitecore TM16GT?

Thanks for the comprehensive data EasyB. Any reason you settled on 6A for the white flat? Curious what it could do in the EE X6 host with 8A.


From my measurment stock M2 has 75 kCd ( 3m lux reading distance )
With Osram 2mm^2 180 kCD ( 3m lux reading distance )

M2 Archer has step down driver set up to 6A to the led.
The stabilization is from 4.2 to 3.3V

You’re welcome. No particular reason for 6A except that it’s a moderately high current I might expect in a quad light with these emitters. Based on my output measurements the throw at 8A should be about 10% higher than at 6A.

Do you know if the Maxtoch M1 and M2 uses the same reflector? The length of the M1 is 10mm longer than the M2.

EasyB I added your test in a first post.

M1 and M2 has the same reflector.
M2 has side switch
M1 has tail switch and this is the reason of 10mm more

Thanks smokuxx1987! Good info, and even more impressive results given your previous readings. Good work.

Thanks for the testing EasyB. :+1:

Ahh, thanks for the clarification. Seems like the 2mm White Flat doesn’t perform too much better than the dedomed SST40. Maybe if the White Flat was driven to 8A, it might pull ahead more.

Nice testing EasyB! Even with the unavoidable uncertainties it gives the insight that these leds from different manufacturers are all close to each other.

Have someone found good centering ring for these and C8? Im using one from old Fenix right now, but it is for little bigger led and is little difficult to tune up although height is pretty good.
Btw org C8+ with XPL HI 6800lux and now 13200 with 2mm2. Own measurement method, maybe better to say I managed to gain 94%.

There is no from the shelf centering ring for Oslon leds, but if you can find one that fits your reflector and has a square cut-out for a XP-size led, you can make your own second cut-out for the Oslon led at 45 degrees from the XP cut-out using an exacto knife or scalpel, like I did for the mini-GT :

Wow! Nice work :o