Djozz, thanks for this, this will be a great little backup light for hiking, starts high and keeps it pretty good for 4-6 hours, that is what I was looking for. Much appreciated.
Measured up to 7.5 hours now, time to go to bed. Will have another look tomorrow if there is still light, I assume that just as the unmodded C01 it will drain the battery to completely empty. The runtime chart sofar:
Hmm…no regulation without a sense resistor to regulate. I guess I should have seen that coming.
I assume with something in between, like a 10 ohm resistor, we’d see in the ballpark of 12-14 lumens steady for maybe 2 hours or so, then the long decline.
Another datapoint, 14 hrs / 0.6 lumen.
Yes, no regulation, I already noticed that without resistor it does not light, it is simply is series with the led somewhere I guess (before or after boosting?, no idea how that works really).
I’m not fanatic in constant output, a steady decline is useful, like the incan days, there is not so much that demands steady brightness and a slowly fading light does not leave you with surprises.
I had ruined one black C01 while finding out about the potting. So it was spare for some fun. 
(did this to a sk68 too a couple of years ago)
LOL it`s even cut one of the Vias in half! 
That is one awesome pic! 
Well done. You can’t deny the potting crew did a good job on that one.
BTW I downloaded a copy of the SK68 picture for “recreational use”, I can’t help smiling.
Yes, that one was the best ever because of the irregularities and moving parts in the design
Looks like you could shorten the light by trimming/sanding the head and “reflector” shorter too.
Great pics and RIP C01 used for testing…
All hail the “in the name of flashlight science” !!! 
Thanks djozz, that’s an awesome photo and cut!!!
Neat, a physical cross-section of a light is way cooler than any CAD diagram!
Two more datapoints: 14hrs 0.6lumen, 24hrs 0.1lumen. I call this test a day Battery voltage is 0.57V now.
Wow, this looks nice. One unsuspecting question: is such a test available for the stock Sophia LED C01 as well?
Just in case anyone had any doubt remaining about whether there is an O-ring around the LED!
In fact, this shows it is better installed that I expected - there is a full groove for the O-ring. On the Sunwayman R01A, it is merely held in place in a shallow counterbore by the flange at the base of the emitter.
Great idea for the dead light, and nice work cleaning it up. I really like cutaways, even when it’s a simple item. There’s even a museum in my area that has an entire tank cut in half like this. I spent probably close to an hour studying it last time I was there.
Also, since I looked it up, here’s the SK68 cutaway post:
I think that someone did that for the Yuji led version, maybe even me :person_facepalming: but it is probably buried in this long thread somewhere, and this Sophia version will not be miles different. Think the same curve as above but starting at 7 lumen, less fast decline and stretching out to over 40 hours.
Thanks, sounds very reasonable.
The cross section is funny and inspiring as well
There is a runtime test of the 2018 Yuji version near the end of this review:
It made it nearly 10 hours of regulated output on a 900mAh NiMH cell. Since it is the same driver, and the forward voltage of the Sophia is very similar to the Yuji, performance of the new batch should be very similar.
With the higher initial voltage of an alkaline and their higher capacity at low loads, it should do a little better with alkaline.
I would plan to do an alkaline runtime test with the ceiling bounce app when I receive mine, but I don’t think I have any fresh alkalines in my house. I use NiMH for all important applications, and for everything else, I’ve found that the battery recycling bin at work almost always has plenty of cells in it that are over 1.5V.
One more thing for this thread.
On request of my 10 yrs old son.
He noticed that I had a new batch of C01’s and he remembered the fun of torturing it 1.5 years ago, so he demanded a fresh test. Who am I to deny anyone a flashlight test? , so there we went, and with him 1.5 years stronger I was not entirely sure. But the C01 (a black and potted one) survived fine again, battered but fully functional.
