Few years ago, I ran my UA5 and a Hosa off my WalMart battery. Because the UA5 has reverse polarity, the "tip" is actually the shaft. When I plugged in the battery, the UA5 plug touched the Hosa plug and the battery shorted. Plugging it at home again reset the battery, and it still works great.
I changed out how I power my UA5 and never had the problem again.
I have also heard of folks that had the same thing happen to them - that their battery shorted. The batteries always reset upon plugging into the wall.
I'm guessing your battery shorted for some reason, maybe when you plugged it in you plugged in crooked and that shorted it. Not sure...
I'm thinking your battery should be fine, that these batteries have a "fuse" that shuts the batteyr down when it shorts. And then it resets upon plugging it in... Like I said, I've never had issues since that one time...
Good luck, hope that helps!
Terry