Interesting point I discovered was when I was looking into repacking the TX batteries for my 14MZ was one website showed a Fromeco "re-lion" pack (3600mAh form memory?) being used for the cells. The particular cells in that particular pack needed to be charged to 4.3V/cell to get anywhere near the rated capacity as indicated in the manufacturers data sheet for that particular cell and according to the manufacturers discharge data only charging to 4.2V/cell you struggle to get 2/3rd rated capacity.

It was an eye opener to me because unlike li-po's which we charge to 4.2V/cell, I believed all Li-ion cells could only take 4.1V/cell like in my cordless drill. I ended up going for a panasonic cell designed to be charged at 4.2V/cell for the TX battery.