You need to rule out a software issue and also rule out bad battery.
Look at the apps you have running, and don't forget apps that run in the background when closed. Make sure everything (except the 5 core BlackBerry apps) is trully exited. If you have to, do a security wipe (back up first) and select the option to delete user installed apps.
If it isn't software, try another battery. Borrow one if you can.
If it isn't software and isn't a bad battery, it would appear the problem is with the BlackBerry handset. Posted via BlackBerryForums.com Mobile