In this case, it wasn't the voltage, which had been brought down to 5v by the motor controller, it was the 160+amps. Not milliamps, amps (3300 mah, 50c battery).
I wasn't paying enough attention when soldering a plug onto a 7 cell 5800mAhr 40c battery once. I melted the tip of my iron, and pretty much vapourised the plug's contacts... (The battery seemed fine about it - I got 6 or 8 months out of it powering a bicycle before it started to show signs of imminently-firey puffiness...)