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?
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.
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.
Currently, Sofirn‘s engineering is working on a prototype, maybe even a whole new driver. Once that has happened I plan to discuss the result of the UI poll with them to see if we keep on using the „high-low“ UI or move on to a more advanced UI (at higher costs). Eventually, Sofirn is going to launch the manufacturing process. Maybe they will only offer deep red or both red and deep red, depending on their sales forecast and supply in components.
I don’t have any confirmed updates yet but I‘ll keep you updated.