The 8330 is different than any other phone I've had. If the battery is low, and starts beeping, it will take a little while to stop beeping when you plug it in. Instead of stopping right when you plug it in, it will continue until it is no longer at the critical battery level. And like you said, it will keep beeping while you're on a call even if you plug in. Annoying a bit if you're talking to the wife and can't hang up.
![Smiley](http://www.blackberryforums.com/images/smilies/icon_smile.gif)