As for condemning that pack outright................

One of the most valuable tools we have available to us nowadays is the smart charger. The Accu-Cycle Elite and the TritonII are examples. Their hidden value is how well they tell when one of our batteries is dying on us. Every time you recharge, if you look at how much capacity had to be returned to the battery and think about how much you used that battery flying that day, you have an idea if the sucker is starting to lose it's capacity. And you can then use the greatest diagnostic function we've ever had. You can cycle the sucker and see if it's really going bad.

Don't trash that battery without a trial. If you don't have a smart charger, it's time to get one. And you have an excellent idea why it's good to have. It's worth putting off the next model or engine to get one.

As for the crash...... who knows, but it could be anything that wasn't looked at.

Like a throttle servo that is stalled at WOT and drains a perfectly good battery in flight.