off of a P4 P60 module using a 18650 lo-ion protected cell i get over 4 hours at 90-100 lumins runs nice and cool. same setup using 2 x rcr123 cells charged to 3.7v nom (4.2v fresh off the charger) so 7.2v i get approx 150 lumins and 60 minute runtime, but it runs very hot even thou the module is rated to max of 18v.

for me led is the way to go, one note of caution for everyday use cheap beater lights are fine but if your life depends on the light get a good quiality one and spend the extra money.