Make it Four...
those three incidents plus the battery pack that Secura burned up in 2006--do you suppose that overcharging just might possibly be involved here, considering the charred remains of a battery thermal runaway, even though supposedly the FDR did not show evidence of overcharge and thus thermal runaway did not occur. Seeing is not believing...
What connects to the battery pack? The battery charger unit and the APU controller. One is a current source, the other a current sink. Overcharging can be caused by overcurrent too, not just overvoltage...although 32 volts is too high for trickle charging that chemistry.