Ok, so I got a light in the other day. The light claims 1000 lumens on turbo at 3.1 hours. High at 600 lumens for 3.3 hours. Then 250 lumens for 7.5 hours, and 30 lumens for 70 hours. These times seem fairly good right? While the turbo isn’t probably 1000 lumens, it still seems in the 700-800ish ballpark. 3.1 hours is pretty good right? And 30 lumens for 70 hours? Thats a ton of time. I’m currently testing the runtimes, so I’ll see how well those runtimes match up. I’ll be honest though, I haven’t been paying attention to numbers as long as many of you. So what are some great times as far as you know? I think long runtimes are great for camping trips. But I’m curious how you think these runtimes stack up? I’m using an xtar 3100 and the light uses an xm-l u3.
about 1 hour on high but that depend on the driver and the cell itself,just my experience until now.
another member here know better than i do 
Measure the current draw at the tail cap on each mode. That will give you a pretty close estimate with a little math.
Capacity of the battery in mah divided by the current draw in milliamps equals run time in hours. Multiple by 60 if you need minutes.
3000mah battery at a 1500ma draw will run close to 2hrs or 120 minutes.
3000/1500=2…….2 x 60 = 120
You really can’t trust most ratings on china made lights, lumens or run time.
A XM-L at 1000 lumens would have to be driven at 3 amps or more to achieve 1000 lumens. The highest capacity 18650 on the market is 3400mah. At 3 amps you should get maybe a little over a hour of run time. That’s why you have to take a current reading, their stated run time at 1000 lumens don’t add up.
3 hours at 1000lm is nice fantasy that is far from reality
Check current draw at each level and divide by battery capacity to get approximate runtime (i say approximate because brightness will fall as the battery drains, giving more runtime at lower brightness.
For example a 2600mAh sanyo 18650 when coupled with a 2.8A (2800mA) linear driver will give about 1 hour despite the fact 2.8A is more then 2600mAh because if the linear driver effect. This would give about 700 lumens out the front of the light on an XM-L chip light and start gradually getting lower due to lumen sag due to heat buildup and after a while when the battery can’t put out enough voltage to keep output on full.
Well the light is an xtar, and it mentions the caveat that the runtimes are approximate and may vary. This isn’t the typical no-name light with dubious claims. So far, the light has been running fairly solidly on turbo at 2 hours and 20 minutes. If there is a decline in output it is definitely gradually, and I’ve been taking some pictures along the way every 20 or so minutes to document it, considering I do not currently own a lux meter. I’m liking the light a lot so far.
I plan on doing tailcap measurements in the future- but right now I’m seeing how well the light performs just leaving it on.
Oh and from what I’ve read the xtar 3100 is a rebranded panasonic- and it’s brand new.
But anyway… anyone have a favorite battery miser?
706 hours on moonlight mode
My P60 dropin has a moonlight low which is meant to give around 800 hours on a 3100mAh