Initial charge of cells... to top-balance cells a a little above the voltage I expect the charger to finish at. Top-balancing is intended to make sure the pack voltage triggers the setting in the charger at the desired end-of-charge voltage in the charge curve without having any cells too far above or below the expected average cell value. I ended up setting to 3.8v,and letting it charge until amps dropped to zero. (several weeks because my inexpensive Mastek puts out less than 10 amps) The factory spec for Thundersky cells 'finish' vpc=3.65, so balancing to 3.80 or so insures that the cells are likely to all hit the 3.65vpc at very nearly the same time when doing a regular charge in series as long as they remain 'balanced'.