As always, great review. Can you tell us a little more about the red battery warning light in the switch...does it start to blink while on? does it blink while off? Did you happen to notice at about what voltage the warning started or can you give a guess? Is it bright enough to be noticeable? Does the blink rate increase as the battery drops down?
Well, this is interesting - there doesn't actually seem to be a low voltage warning on the S10. Sorry for the confusion.
That review text was left-over from my earlier Baton series reviews - I hadn't actually tested for the sensor here. And since my runtimes are largely automated, I don't typicaly notice sensor functioning until I explicitly set out to examine it. This is what I get for posting a review while I am away travelling.
I note in the specs there is no mention of a sensor, and I found no evidence of it on either RCR or CR123A. I will confirm with Olight.
I did a runtime test on med (70lm) with a no-name brand CR123A. When the battery voltage drop to 2.0v after 6.5 hours, the light start to flicker (My Zebralight H51w did the same thing). If I switch to low mode the flickering stops, and it will continue on low for another 30 minutes and then auto shut-off at 1.9v. And it can still turn back on moon mode and last for a very long time.
I saw no sign of flickering in my initial testing, on AW RCR or Titanium Innovations CR123A. But I just tested an old Ultrafire protected RCR, and got high-speed flickering (kind of like a strobe) on Hi, <3.8V or so.
I don't see this on any of my AW cells, so I can only assume it's the circuit's response to a poor quality battery that can't reliably provide the required power.