iPad Not Holding a Charge

The problem I am having is with a 32GB 3G iPad. The device is updated to the latest OS version of 4.2.1. The device will function normally until the battery level reaches 90%. Upon reaching 90% the device will cycle off as if it lost all available charge in the battery. When I try to turn the device back on it shows the depleted battery icon along with the icon to plug the iPad into external power to charge the battery. After sitting for several minutes the device will become active again and show 100% power until it reaches 90% again. At that time the process repeats. I am plugging it into a wall outlet with the supplied AC converter and USB cable.