It’s set up exactly as it is stock, except with a glass lens to keep it waterproof. The TIR optic is within the plastic insert (I assume to reflect light that escapes the optic) so all I had to do was remove the optic and add a lens.
By the way, at this moment all my Sofirn lights work perfectly with 10440 of 3,7V.
C01 gives the same light with alkaline as with lithium. I have only tested momentarily. C01S and SF01 are transformed into small cannons of light, with fantastic WOW effect. I have been using C01S and SF01 with lithium for several days at home for many minutes every day and they work perfectly and they also continue to work with alkaline batteries and with ni-mh, although I like them much more with lithium!
The C01S supports “honeycomb” lenses that smooth the contour of the light beam, such as the old Fenix E05 of 27 lumens:
30 minutes is not bad at all, I’m a bit impressed even by that: I measured 95 lumen, that should be about 500mA through the led and over 1.5A from the battery. The boost circuitry does not eat too much energy it seems.
Btw, a runtime prediction for the low mode: I measured 2.7 lumen for my BLF version, and it eats 29.6 mA from the battery, if the output is steady that makes for 25 hours on a AAA Eneloop.