Sofirn C01R deep red [sold out, discontinued]

I’d be happy with the standard red also


Since we’re talking about red emitters I think it is appropriate if the body also has some kind of red color.

Swapping the sense resistor, or factory customizing the sense resistor for red emitters, isn't overdriving the LED.

As I said before, they could use 0.2Ω or 0.22Ω sense resistors for red emitters and obtain higher output. This driver modification results in more or less matching power output and battery drain figures versus standard white emitters, while boosting the flashlight output. It's a win win situation, the only potential drawback is the need for driver modification, if anything.

Dark green or desert tan anodization will be very wellcome, instead red or wine red, IMHO.

Even I prefer black instead red anodization.


Some comparative figures:

Since the calculation is done for the standard red emitter, it is also fully valid for the photo/deep red one (its Vf may even be a little bit lower).

@ Barkuti: I will talk to Sofirn about the sense resistor tomorrow.

A comment on this old graph of mine: it was in the time that I still used a budget luxmeter (Tondaj) that especially gives largely deviated values for single colours so do not trust the absolute lumen values too much. The curve shapes, currents and voltages should be correct.

As you can see in djozz's output graph, Lux-Perpetua, the raw lumens for the P3 bin red XP-E2 went up from ≈53 at 350mA to ≈75 at 472.5mA in the test station, which is quite substantial. A big difference which the photo red will also enjoy.

Thank you Djozz + Barkuti. I will forward these valuable information to Sofirn and try to convince them taking extra care of the sense resistor. I have no idea how much effort they expect in modifying their C01S driver but with the obvious benefit of significant better output it should be worth it.

Do you guys think it's worth using 0.22Ω resistors for other C01S emitters, too? If it turns out to be general advantage for LEDs like SST-20 2.700K/4.000K 95CRI or LH351 2.700K 90CRI, it should be even easier to convince them.

I see the problem, according to Cree datasheet the minimum luminous flux for a P3 bin red XP-E2 at 350mA/85°C is 73.9 lumens, while you measured just ≈53; (53 × 100) / 73.9 = ≈71.72% of actual output (pretty sure slightly bit larger difference actually since djozz's P3 red wasn't at 85°C).

Interesting, because if Sofirn gets his hands on P4 binned red XP-E2s, if they dare to bump the driver current for red emitters the raw emitter lumens for the red C01R will be 80.6 × (75 / 53) = ≈114. With regards to the photo red, the raw lumens figure will probably be ⅓ of that number for standard sensitivity humans.

Sun, 11/03/2019 - 21:11


0.22Ω ≠ 0.2Ω. Since sense voltage in the C01S driver is ≈350mA × 0.27Ω = ≈94.5mV, with an R22 current is raised to I = V / R = 94.5mV / 0.22Ω = 429.5̅4̅mA. With an R20 current is 472.5mA.

Concerning raising the current for all emitters, that is a different story because they have a higher Vf, this forces the driver to output more power, working harder and draining the battery harder and faster too.

Okay, got it. ;-) I will report about any news as soon as possible.

Interested tn OD green or tan ano!

In for one in Deep Red if the price lands around $11 as expected.

For sure interested in 660nm

Red anodizing preferred, but not necessary

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:


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.