Question about Surefire G2 Flashlight

[Cigar Mike]

I have a G2 (as well as numerous other Surefires, mostly for work) and have had the same problem. It turns out those lithium cells get a little old and under no load still test out at a decent voltage, but can't supply enough current (and therefore the voltage drops way dow) to make the bulb happy when put under load. I am pretty sure a new set of batteries will set you straight.