This is the voltage change of the battery of my
M2P from 100% to 0% battery. You can see two things :
1) The voltage difference between cells is never more than 0.02V
2) The cell voltage drops to 3.58 V when the battery level reaches 0%
Your battery exhibited something totally different :
1) The voltage difference between cells was more than 0.1V sometimes even if the problemetic cell ( #2 ) is ignored.
2) The cell voltage dropped below 3.58 V when the reported battery level was as much as 80%.
It looks like all the cells are bad with cell #2 being the worst. Furthermore, the calibration of the battery was wayyyyy off . To maximize the life of the battery and ensure proper calibration, it is essential to :
1) store the battery at 30% ~ 40% charge level
2) store the battery at cool places. high temperature kills.
3) fully discharge the battery once every 3 months. This is to ensure that the reported % battery figure keeps being accurate.