Unfortunately I haven't carefully monitored the time I've used this so far, so the best I'll be able to do on this set of batteries is estimate my use so far, and keep track from here on out. I'll time the next set exactly.

In the mean time, there is someone over on another forum who tested it with rechargeable 5000mAh NiMH cells. He got 4.5 hours of "good bright light followed by a dwindling faint light for another while". 4.5 hours from a rechargeable is respectable indeed, I may end up taking the rechargeable route on this thing in the future. The Duracell batteries that come with the light are 7000mAh, so I think you can expect 5 hours 45 minutes or so from the batteries that come with it. Then again, I also read that Alkaline are horrible in runtime due to poor high drain performance, so who knows.

What I do know is that I have a 45 minute commute home last night, in addition with about an hour of playing with it on Sunday and helping a friend fix a flat on her car, and the beam seems the same as when the batteries were new. So I’d say I’m currently @ 1:45 or so and going strong, I’ll keep you posted and try to time it exactly on my next set of batteries.