Generally, yes, as long as there isn't a constant drain that will drag one cell past the 0V point and actually started pulling current from the other cells backwards through the very discharged cell. The secret (which isn't a secret now I've posted it here
) is to recharge very slowly until the cell returns to around 3v. As long as the cell isn't held below 1.5v for a long period, it shouldn't have started to eat itself while attempting to produce the natural voltage that chemical combination will produce. It doesn't do them any good that's for sure, but most of the capacity will return if the recharging job is done correctly. Attempt to fast charge them at that voltage/depth of discharge will result in almost instant death of the cell because the lithium will start to plate on the graphite material rather than intercalate, this build up then attract the lithium to build onto the same spot and eventually create a spike that passes through the separator sheet and shorts the two plates out to each other. Because the voltage is still so low the tip will not burn off but rather fuse itself to the other plate, the end of the cell ever holding a charge again.T1 Terry
