I just discharged one of AW's rcr123 cells down to 2.9V and placed it into the longer battery style Nano. Initially, the charger put out about 300 mah then within a minute, settled down to about 200 to 210 mah. Same test with the shorter cell Nano resulted in the same results.
FYI, there is a second thread on the topic
here.
For those not familiar with the subject - Li-Ion cells are tolerant to abuse, nevertheless there are some limits. Current limits are usually expressed in the terms of the "C" current value, where C has the same numerical value as the cell capacity. If it is for example an 10180 cell with 90mAh capacity, the C value would be 90mA.
1C (90mA in the example) is considered the maximum current that can be used if we expect the cell to live longer than a few charges. 2C (ex. 180mA) is the limit where people usually start to worry not only about the cells longevity but also whether or not they will explode during charging. 3C (ex. 270mA) is the overcurrent charge used for the best cells (i.e. probably none of the cells used by most of us in our flashlights) in the UL and BAJ safety tests. The cells are expected not to explode or catch fire during the 3C ovecurrent test but of course they can be dead afterwards.
I think that a 10180 cell would probably have higher internal resistance than an RCR123 cell so the current would be lower than tested by BVH, not much lower though. It is really amazing for me how much Li-Ion cells can tolerate - judging by some CPF posts many people regularly charge their cells with 2C, 3C sometimes even 4C and, except shorter cells life, usually nothing bad happens.