I have HC60 headlamp and experienced unexpected behavior: Poweroutput was set to mid, ie. 210lm, which should not produce enough heat to overhead in normal conditions, also the battery drain should be normal. I went from outside to iluminated room, and after a while, the lamp just shut down, and start blinking for a while. I did not recognise any pattern. I wasn't aware of any reason for low power, so I unscrew the cap, and put it back in, to get the voltage info, and I get info 3.9V, which I then confirmed on charger, which reported same value and reported half drained battery. Manual considers 4.2 max, 3.5 low, so it is say the middle.

So what was it? Why did the light went away? There is plenty of power, power output is moderate, it shouldn't quit. And what could be that blinking?

Why I'm asking: I don't like surprises happening in locations, where surprises must not happen. I always have at least 1 backup light, sure, but still. So any ideas, what could that be? Manual does not "allow" this behavior