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.
Conclusion:
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.
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.
Thanks,
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.
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?
Thanks,
Do you know if the Maxtoch M1 and M2 uses the same reflector? The length of the M1 is 10mm longer than the M2.
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?
Thanks,
Do you know if the Maxtoch M1 and M2 uses the same reflector? The length of the M1 is 10mm longer than the M2.
M1 and M2 has the same reflector.
M2 has side switch
M1 has tail switch and this is the reason of 10mm more
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?
Thanks,
Do you know if the Maxtoch M1 and M2 uses the same reflector? The length of the M1 is 10mm longer than the M2.
M1 and M2 has the same reflector.
M2 has side switch
M1 has tail switch and this is the reason of 10mm more
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%.
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 :
I will have a look again when I use the led in a new host (not in the mini-GT because it has a new led already), but I noticed nothing in the beam that pointed at the rectangular die shape, in this smooth reflector it produces a fine distinct hotspot with limited corona.
Corona in the X6 was round. I guess it makes sense since a reflector takes a circular average of the LED to make the beam. The same reason a square LED makes a round beam. I would expect a slightly distorted spill outline though.
Corona in the X6 was round. I guess it makes sense since a reflector takes a circular average of the LED to make the beam. The same reason a square LED makes a round beam. I would expect a slightly distorted spill outline though.
I may be remembering wrongly. If so, feel free to help me out.
My understanding has been that a properly focused parabolic reflector takes aim from one central spot. All the light from that one spot forms the hot spot of the beam, and the rest of the light from the die is out of focus. So, the die shape shouldn’t affect the hot spot at all. If it is a particularly well focused reflector, the corona may show some rounded version of the die shape. But it depends also on how bright the spill is, and how it blends from corona to spill.
—
The Cycle of Goodness: “No one prospers without rendering benefit to others”
- The YKK Philosophy
Corona in the X6 was round. I guess it makes sense since a reflector takes a circular average of the LED to make the beam. The same reason a square LED makes a round beam. I would expect a slightly distorted spill outline though.
I may be remembering wrongly. If so, feel free to help me out.
My understanding has been that a properly focused parabolic reflector takes aim from one central spot. All the light from that one spot forms the hot spot of the beam, and the rest of the light from the die is out of focus. So, the die shape shouldn’t affect the hot spot at all. If it is a particularly well focused reflector, the corona may show some rounded version of the die shape. But it depends also on how bright the spill is, and how it blends from corona to spill.
Not out of focus, but rather off-center.
A rectangular die (right) would make a slightly oblong shaped spot which is not really noticeable because of corona and also the fact that the CSLPM1.TG is fairly close to square.
Today I putted one 1mm2 white flat in a SMO reflector Convoy L6 with short tube and single 26650. You need to wait a day to measure. I’m at work and I only got a little time at home to done measuring while dark but before work.
Edit: added images.
Not out of focus, but rather off-center.
A rectangular die (right) would make a slightly oblong shaped spot which is not really noticeable because of corona and also the fact that the CSLPM1.TG is fairly close to square.
Well, any point that is “off-center” from the focal point is what I’m calling “out of focus”. Perhaps I should have used another word, like “detuned” instead?
—
The Cycle of Goodness: “No one prospers without rendering benefit to others”
- The YKK Philosophy
Corona in the X6 was round. I guess it makes sense since a reflector takes a circular average of the LED to make the beam. The same reason a square LED makes a round beam. I would expect a slightly distorted spill outline though.
I may be remembering wrongly. If so, feel free to help me out.
My understanding has been that a properly focused parabolic reflector takes aim from one central spot. All the light from that one spot forms the hot spot of the beam, and the rest of the light from the die is out of focus. So, the die shape shouldn’t affect the hot spot at all. If it is a particularly well focused reflector, the corona may show some rounded version of the die shape. But it depends also on how bright the spill is, and how it blends from corona to spill.
Not out of focus, but rather off-center.
A rectangular die (right) would make a slightly oblong shaped spot which is not really noticeable because of corona and also the fact that the CSLPM1.TG is fairly close to square.
No, the projected images of the dies are rotated as you go around the reflector. Make a pinhole in a piece of Al foil and move it around the reflector to see.
No, the projected images of the dies are rotated as you go around the reflector. Make a pinhole in a piece of Al foil and move it around the reflector to see.
They do not rotate.
They get stretched when the angle between the LED and reflector is large (aka near the center of a forward-facing reflector), but they do not rotate.
Corona in the X6 was round. I guess it makes sense since a reflector takes a circular average of the LED to make the beam. The same reason a square LED makes a round beam. I would expect a slightly distorted spill outline though.
I may be remembering wrongly. If so, feel free to help me out.
My understanding has been that a properly focused parabolic reflector takes aim from one central spot. All the light from that one spot forms the hot spot of the beam, and the rest of the light from the die is out of focus. So, the die shape shouldn’t affect the hot spot at all. If it is a particularly well focused reflector, the corona may show some rounded version of the die shape. But it depends also on how bright the spill is, and how it blends from corona to spill.
Try the pinhole experiment I described in the post above to see how it works. Every little part of the reflector projects an image of the die. The parts near the outside project a smaller image and this forms the “hotspot”, the parts of the reflector near the center project a larger image and this is the “corona”. Additionally as you go around the reflector the images rotate, so this is what I mean when I say it takes a circular average around the center of the die.
No, the projected images of the dies are rotated as you go around the reflector. Make a pinhole in a piece of Al foil and move it around the reflector to see.
They do not rotate.
They get stretched when the angle between the LED and reflector is large, but they do not rotate.
They do, we discussed this before. Have you tried it?
They do, we discussed this before. Have you tried it?
Yes, they do not rotate.
This is the same for lenses, record reflectors, and forward-facing reflectors.
I will literally upload a video right now for you to see.
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.
Conclusion:
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.
Thanks,
That's just like . . . your opinion man.
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.
That's just like . . . your opinion man.
Thanks for the testing EasyB.
djozz quotes, "it came with chinese lettering that is chinese to me".
"My man mousehole needs one too"
old4570 said "I'm not an expert , so don't suffer from any such technical restrictions".
Old-Lumens. Highly admired and cherished member of Budget Light Forum. 11.5.2011 - 20.12.16. RIP.
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.
link to djozz tests
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 :
link to djozz tests
Wow! Nice work
djozz, what does the corona look like?
Project Excalibur - Next Generation LED Thrower (UPDATE 2018-01-15: 1.7Mcd)
Portable Thrower Comparison
I will have a look again when I use the led in a new host (not in the mini-GT because it has a new led already), but I noticed nothing in the beam that pointed at the rectangular die shape, in this smooth reflector it produces a fine distinct hotspot with limited corona.
link to djozz tests
Corona in the X6 was round. I guess it makes sense since a reflector takes a circular average of the LED to make the beam. The same reason a square LED makes a round beam. I would expect a slightly distorted spill outline though.
Managed to get pretty good, although could be better.
I may be remembering wrongly. If so, feel free to help me out.
My understanding has been that a properly focused parabolic reflector takes aim from one central spot. All the light from that one spot forms the hot spot of the beam, and the rest of the light from the die is out of focus. So, the die shape shouldn’t affect the hot spot at all. If it is a particularly well focused reflector, the corona may show some rounded version of the die shape. But it depends also on how bright the spill is, and how it blends from corona to spill.
The Cycle of Goodness: “No one prospers without rendering benefit to others”
- The YKK Philosophy
Not out of focus, but rather off-center.
A rectangular die (right) would make a slightly oblong shaped spot which is not really noticeable because of corona and also the fact that the CSLPM1.TG is fairly close to square.
The OPTOFIRE - 4.63Mcd aspheric LED flashlight The SYNIOSBEAM - 10Mcd recoil LED flashlight List of the farthest throwing flashlights
Today I putted one 1mm2 white flat in a SMO reflector Convoy L6 with short tube and single 26650. You need to wait a day to measure. I’m at work and I only got a little time at home to done measuring while dark but before work.
Edit: added images.
Reviews: Lumintop GlowI, Sofirn SP36, Convoy 4X18A, Convoy M21C, Brinyte SR8 Rescue Angel, Astrolux MF01 mini, Astrolux FT03S, YLP Sherp S15, Sofirn SP40, YLP Panda 3R and Unicorn, Armytek Prime C1 Pro, Acebeam M50, Imalent MS18, Convoy M3, Nitecore TIP2, Imalent RT70, Wuben T70, Sofirn SP32A, Thorfire VG15S, Thorfire VG10S, Thorfire TG06S
Mods: Imalent MS18 dedoming, Astrolux MF01-20K, Small sun T08 MT-G2, Eagle eye X6 triple XPL, Ultrafire F13 MT-G2, Convoy C8 XHP70, Solarstorm T3 triple XP-L HI
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Well, any point that is “off-center” from the focal point is what I’m calling “out of focus”. Perhaps I should have used another word, like “detuned” instead?
The Cycle of Goodness: “No one prospers without rendering benefit to others”
- The YKK Philosophy
No, the projected images of the dies are rotated as you go around the reflector. Make a pinhole in a piece of Al foil and move it around the reflector to see.
They do not rotate.
They get stretched when the angle between the LED and reflector is large (aka near the center of a forward-facing reflector), but they do not rotate.
The OPTOFIRE - 4.63Mcd aspheric LED flashlight The SYNIOSBEAM - 10Mcd recoil LED flashlight List of the farthest throwing flashlights
Try the pinhole experiment I described in the post above to see how it works. Every little part of the reflector projects an image of the die. The parts near the outside project a smaller image and this forms the “hotspot”, the parts of the reflector near the center project a larger image and this is the “corona”. Additionally as you go around the reflector the images rotate, so this is what I mean when I say it takes a circular average around the center of the die.
They do, we discussed this before. Have you tried it?
Yes, they do not rotate.
This is the same for lenses, record reflectors, and forward-facing reflectors.
I will literally upload a video right now for you to see.
The OPTOFIRE - 4.63Mcd aspheric LED flashlight The SYNIOSBEAM - 10Mcd recoil LED flashlight List of the farthest throwing flashlights
https://photos.app.goo.gl/kjPF4mV5SJZFDQwYA
The OPTOFIRE - 4.63Mcd aspheric LED flashlight The SYNIOSBEAM - 10Mcd recoil LED flashlight List of the farthest throwing flashlights
what is the best kind of 18650 battery without blowing up this LED?.
panny 18650B 3400 6.6A? 18650 3500 10A?.
thanks
Virence Custom Built; ArmyTek Viking Pro E21A 6500k 9080 Quadtrix, Jetbeam AAA 9080 E21A 9080 5700k, Jetbeam AAA Nichia HCRI Red Led.
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