When mine went red they still would hold 70V too, but they still turned red. If the rene_canlas recovery method
did not work for your battery, that means the cells are too far gone to revive. The next recovery method would be replacing the bad cells. That would move you over to this thread
Rebuilding Segway i2 battery
https://forums.segwaychat.org/showthread.php?t=36985