np with the color, standard red body color works for me too…
@ Barkuti + Djozz: Sofirn's engineer says there is not enough space left on the C01S driver to use an R20 sense resistor. He also tested the XP-E2 deep red LED using the C01S driver.
His feedback is:
红光vf太低，红光低亮的时候，这个电压不足以支撑单片机工作了
the vf of red led is too low, when at low mode, the voltage is not high enough for the chip
What do you suggest Sofirn to do?
As I’m not an electronics person, the short answer is: I don’t know.
People like HarleyQuin, DEL, LoneOceans could maybe help designing a driver.
Btw, it sounds a bit surprising that a R20 resistor can not be added. Perhaps not with the current layout but with some shifting traces or switching positions I can imagine it can be done. In that case maybe Lexel is your partner, if he is willing to do that, if Sofirn can provide the current driver layout digitally, he is very handy with drawing lay-outs, and he is fast.
Interested in 1x deep red 
If I put 红光vf太低，红光低亮的时候，这个电压不足以支撑单片机工作了 in Google Translator I can discern among a bit of nonsense :-) that the Vf of photo red emitter is too low for the driver to work properly.
So, it doesn't matters if they can't fit an R20 in the C01S driver (I bet I'd fit it ;-) but of course they're speaking from a manufacturer's pragmatic viewpoint), as djozz points out the C01R needs a new driver. 
Thank you both. I asked for the driver schematics but I could imagine they don't want to distribute them around for reasons of nondisclosure. Anyway, I try my best to keep the link alive between BLF and Sofirn's engineering. I was told that Sofirn's engineer will find an alternative way to make the XP-E2 deep red work with the C01S driver. I don't have any details yet. Maybe they find an alternative way to modify the sense resistor. As far as I can understand their response Sofirn tries to avoid using an individual driver (design) for C01R as this would go in line with significant cost increases.
[quote=Lux-Perpetua] …
Thank you both. I asked for the driver schematics but I could imagine they don't want to distribute them around for reasons of nondisclosure. Anyway, I try my best to keep the link alive between BLF and Sofirn's engineering. I was told that Sofirn's engineer will find an alternative way to make the XP-E2 deep red work with the C01S driver. I don't have any details yet. Maybe they find an alternative way to modify the sense resistor. As far as I can understand their response Sofirn tries to avoid using an individual driver (design) for C01R as this would go in line with significant cost increases.
[/quote]
The C01S driver design is no big deal, many people here could even design one from scratch in little time…
As said before (based on Sofirn engineer's report) the C01S driver needs some modification to properly drive photo/deep red emitters. It is a bit surprising, imho, as alkalines will quickly drop below 1.5V under load (I doubt there is a problem with Ni-MH).
Concerning the problem with the sense resistor, it seems like a porky pie to me, smells like they're hesitating to make further driver modifications plus having to purchase a reel of sense resistors. But in light of the engineer's report, they will have to modify the driver for the C01R. So, I find little reason not to swap the sense resistor too. You can tell 'em this without beating around the bush. ;-)
Ok, so THIS is the point where the C01R idea officially mutates from a simple “give us a small run with a different LED and a colored body” into “please rework an existing production template and build something special just for our small run - please?”
In layman’s terms, what exactly do we loose if they give us a red LED on a standard L/H C01 driver?
Is the issue only affecting XP-E2 Photo Red 660nm, or is XP-E2 Red 625nm also affected?
Interested in 2x deep red please
They both are very low voltage.
If I understood everything correctly, the C01S driver "as is" will not be able to handle the low Vf of XP-E2 deep red at low currents (= moonlight or low). Eventually, we would only have a high mode here without doing some tweaks on the circuitry. Consequently, they look for a solution that can be deployed without changing the entire driver design. I hope I get some detailed news soon but for the time being Sofirn told me they will find a way to make their driver work with XP-E2 deep red.
And what about to try different LED?
It will be hard to find another comparable LED with "better" specs in terms of the LED's forward voltage (Vf). They may try Samsung's LH351H or Luminus' SST-10R but I doubt these will be much different to Cree's XP-E2 deep red. Furthermore, it's challenging for Sofirn to source less frequently demanded LEDs as they have contracts with certain suppliers who cannot supply every LED we deem to fit into the C01R. :-( Provided that there was enough demand for further color-LED versions, e.g. with XP-E2 blue, green, amber, ..., it could be worthwhile to develop a separate driver. But for now, I hope they can surprise us soon with an alternative idea.
I once received and fiddled with a C8S Sofirn buck driver (sense voltage: :facepalm: ≈0.23V), it worked but as usually happens with very high sense voltage drivers can't really say great things of it from a modder's viewpoint, imho burns too much power in the sense resistor and this means lesser efficiency and small room for overcurrent purposes.
What where the Sofirn managers thinking when planning the C01S? They probably cheapened to the brim in the driver for maximum cost savings, and the price paid is lack. It strictly is a boost driver, blows up with li-ion cells (no multi-chemistry). Its sense voltage, at ≈95mV, could be better, and also detrimentally contributes to a high minimum Vin to Vout difference.
Well, hope they can do some optimization to the driver for it to end up working. I wouldn't really mind if it means the low mode ends up being slightly more bright than it should, just slightly of course. Hope they also rework the current sense thing to reduce the Vin to Vout difference, and as a side effect we get improved driving current for red emitters.
The color E17A is a 3V LED due to being phosphor converted from blue.
However, it probably won’t appear as deep of a shade of red as a photo red, nor be as efficient as standard red.
Additionally, it was already mentioned Nichia’s can be hard to source in small to medium quantities, and as reported by Clemence, these chip scale packages are more difficult to solder to a board. Perhaps they could buy enough from Clemence, but almost certainly at a higher price than buying straight from a distributor, especially if Sofirn normally has their LED’s flowed onto PCB’s by a shop with pick and place equipment and other aids.
Interested in 2-4.
Id buy 1 or 2
Interested in 1.
Sofirn told me a prototype will be ready soon. According to their engineering dept. they will not be able to reach 470mA but they will try to get as close as possible.