No, because the current will fall rapidly towards the end and the led will still make a lot of light.
You are. Most XMLs will still light up at 2.5V.
XML flashlights with simple drivers (direct drive or linear) will make light for hours, but not much. I once ran a cheap Trustfire 2400 down in my UF980L. It took hours and in the end I measured about 50mA and a voltage of 2.7V. Protection didnt trip and I dont know how long it would have taken.. but it was rather dim at that point.
At about 3.6V the low level indicator flashes on the 105c driver, so if i am getting 2470 mAh from the sanyos that means i am only getting 2074 mAH from the NCR18650B.
Am i missing anything?
Would this also suggest these batteries would work best in something that can still run on 3.3 to 3.6V?
The cells are 3.6V while there’s a load on them, so if you turn the light off, the voltage should bounce back to 3.7-3.8 volts. That’s why you’re not getting the full capacity.
The cells are about 3.0V with a load on them, thats the low voltage warning
Whoops, nevermind then. 
If you look at LiCo discharge graphs, you can see that they still have juice left even until 2.75-3.0V. That’s where the extra 400mAh may have gone. 
Edit: The discharge graphs show volts of cells under load, so nevermind again.
No, thats right. The Sanyo cell is still one of the best cells for simpe single cell flashlights. When used in series or with a good boost driver the ones from Panasonic provide more capacity.
You have to be very careful with load/no-load voltages, there is a significant difference, especially at the low end. Even if you discharge down to 2.5 volt the cell will recover to above 3 volt when the load is removed.
To find curves with loaded voltage, all my battery tests can be used, there are loads from 0.2A up to 5A for most batteries.
For unloaded batteries I have only done a few tests and only after 1A and 3A load.
Yes, if you apply a high load like you do in your tests. But if you run a cell down to 2.5V in a flashlight with an AMC based driver, the cell wont recover noticeably.
Correct, the recovery is depend on the load and a led with only a weak glow is a very low load.
This also means that relying on over discharge protection at the low brightness settings is not a good way to keep batteries healthy (At high brightness the over discharge protection is a good protection).
The safest way is to monitor the cell voltage with a DMM. Different drivers and batteries will produce different results. The DMM will tell you without a doubt. Once you do this a few times you should learn the characteristics of the particular battery driver combo safe discharge time. You get that little light come on in your head that says I bet that battery is almost dead. Time to charge. Or you can check it with the DMM to be sure.
Thanks HKJ for stepping in here and clarifying.
Thanks for noticing this thread, i was initially going to PM you and ask your opinion 8)