Yeah, they're gone. I came into possession of a pack where half of the cells were below a couple of volts. Every single one of those would not hold a charge. The lower voltage cells self-discharged faster than others, but all were ultimately not usable.
The implication of self-discharging is that the separator is damaged and charge is leaking across that barrier. The risk (beyond your pack constantly going out of balance) is that in actual high current usage that membrane damage will get worse and allow enough current to flow to cause local heating, more damage, more heating, etc. You won't necessarily get runaway cells spreading through the pack like other lithium chemistries, but bad lifepo cells will overtemp and vent.
The implication of self-discharging is that the separator is damaged and charge is leaking across that barrier. The risk (beyond your pack constantly going out of balance) is that in actual high current usage that membrane damage will get worse and allow enough current to flow to cause local heating, more damage, more heating, etc. You won't necessarily get runaway cells spreading through the pack like other lithium chemistries, but bad lifepo cells will overtemp and vent.
