[modmonster]

there are several ways a cell can fail. it can fail open circuit or it can short out. if it fails open circuit then that battery will stop and the others will have to take over as already mentioned.

if a cell shorts out then there will be an imballance and the other batteries will try to charge it and will most likely over charge it and cause damage (to the other cells in the week battery). also cells when they are damaged can show low voltage with out being shorted out so and imballance can happen like this too altough it is usually less critical because the damaged cells will usually rise back to normal voltage.