Awesome, thanks for the update. Any beamshots of that light? Based on what it pulls on direct drive, what’s your estimate on amps each led is seeing? Thanks
Supposed a quad SST-20-DR in an Emisar D4 (with the 80% FET UI for 219C I guess) can handle the current, won’t it be “better” since it’s reported the FET+1 can achieve a lower lowest level compared to the regulated linear-FET driver from the KR4 of which it is reported that is has problems providing a stable non flickering moonlight mode?
Unfortunately, I don’t know what it pulls on direct drive. I wish I knew, but I don’t have the right equipment to measure it. I know the LEDs did not die even with a fully charged Samsung 30Q.
Beamshots of monochromatic lights can be misleading. What your eye sees is different from what the camera can capture.
Check out these C01R beamshots:
I have a D4V2 with SST-20 4000K. To my naked eye, the beam has the same profile (throwy), except it is red, and the red color is exactly the same everywhere. If I took the SST-20 4000K beamshot and edited in Photoshop to look red, that would be exactly what it looks like.
@lightdecay, how low is the moonlight mode on your D4 with SST-20-DR? Low enough to somewhat preserve night vision?
Djozz and others, is it possible that the SST-20DR, xp-g3 in red, or the Osram Flats in Red would have better thermal characteristics than previous red leds? I’m building a C8TT head with a C8f reflector and the more I think about it, the less a triple red light makes sense due to the heat of three leds, even with that C8tt host and a noctigon 32mm instead of the C8F board. Is 3x red leds on the same MCPCB/piece of copper going to go down in output really quickly to the point of diminishing returns on a triple? I was planning on using 3 sst-20 DR’s, but maybe re-thinking it. Thanks
@mountainair26,
Lately, there was an interesting discussion with Djozz about SST20-DR's thermal and electrical sustainability in my SP10R thread. It began right here...
https://budgetlightforum.com/t/-/63027/56
My experiences with red LEDs have all come to one common result: They get hot very very fast.
Sofirn's C01R with XP-E2 photo red is driven slightly above 1A forward current on High mode, getting quite warm after a minute or so.
Amutorch's New VG10 using Osram's Ostar Projection Compact LE R Q8WP (measured tailcap current: 5A!) gets insanely hot after 2-3min on full power.
I asked Barry (Sofirn) to try testing SST20-DR in Sofirn's C8F 21700 light but that would require a new, different driver. The FET DD driver would probably kill those 3 low Vf emitters when used on Turbo. Hank probably uses the 5A or 7.5A CC driver for his KR4, driving 4x SST20-DR. I suppose it's better to use more LEDs driven at less current than pushing only 1-3 LEDs to their limits.
If you want to get the best current-sustainability and output, you may want to try Luminus SBT90-R (13.5A with ~ 1.500lm). But this LED costs about $ 56,00 each and requires a special reflector/gasket as it's not a typical 3535/5050 emitter.
I have a red LED from Clemence in a Jetbeam AAA.
its a HCRI red
would the XPE red and so on be the same HCRI ?
Luxeon Star comes in a wide range of colors.
I’ve used their amber stars for modding and been quite happy with the results.
What do you mean by HCRI? Monochromatic red light is never high CRI, by definition it only has a single color.
The quads I bought from Hank use direct drive turbo for SST-20-DR.
It works fine with a single 18650 or 26650, but it is probably a lot less efficient than the 7.5A CC driver and it probably doesn’t produce a lot more light. If it is using a lot more current (I don’t know as I never measured it), it could cause your battery to wear down faster, but otherwise it is fine. My SST-20-DR quads get hot a lot slower on turbo than SST-20 4000K quads, so it might not be that bad.
so what makes clemence red led light different to say the normal red?.
i used cree luxeon rebel and ledengin lz4. rebel is almost identical to cree, similar die size, current, optics used, ledengin lz4 however is very different, more power, special optics needed, wider beam. need boost driver using 1 cell, i’m no hunter, i build multicolor lights for fun.
haven’t used modern osram leds, yet.
correct, red leds are not High CRI
wider spectrum:
“these color E17A have much broader spectrum coverage than conventional pure color LED”
xpe2 660nm (image thanks to djozz)
another example:
Thanks for all the informative responses. Really good information.
If only being used in high for maybe 30s or less, most of the time less, what’s a rough “sweet spot” current for and sst-20-DR in a triple? (c8f or s2+ with optics) Somewhere between 1.5-2a even though sst-20 is rated to 3A? I was thinking of using the 6a linear Convoy Driver intended for the sst-40 for something around 2a or less on high to each led. Is this a bad choice or does anyone have a good driver recommendation for triples with 1 cell input and 3x parallel red leds? I’m guessing that a buck driver wouldn’t really work with only one cell and 2a current to each led for very long if at all.
This could be the first light I’ve built in a couple years that does not over-drive the led past the data sheet numbers.
Datasheet says 2.1V typical, 2.6V max at 700mA, +1V at 2.0A, so 3.1V typical, 3.6 max at 2.0A, it could work as long as there isn’t much difference in Vf between the LEDs.
Sofirn is selling XP-E2 Photo Red 660nm, used in C01R, for $1.59 each. There are 7 available right now.
https://www.sofirnlight.com/xpe2-red-led-660nm-p0113.html
Any new promising red led? 
I wish Sofirn would put the XP-E2 in one of the two banks on the LT1 camp lantern. Red doesn’t attract bugs while camping.
I wonder how that would look in an FW3A:
- 2x cool white XPL HI or LH351D.
- 1x red LH351H