I gave my Dorcy K2 a good workout outdoors tonight and I think I noticed the brightness occasionally drifting downwards for a moment and then back up again. I don't know if this is battery fatigue, regulator drift or some combination of both.

I was pretty impressed with the runtime; I was running it continuously for about 2.5 hours and it was still going strong. I'm just wondering about the brightness "breathing" up and down like that.

Has anyone else noticed this?