Make sure it is inserted properly. There are two indicators that it is correct. The remove arrow is on the front and point up; and the gold plates on the bottom match the gold prongs on the device.

Make sure the battery is inserted before placing the device on a charger.

Make sure it is completely dead before placing it on the charger. There is a battery icon on the top of the screen. When it is empty, the battery is dead.

The best way to get maximum use out of your battery make sure you are using an Alcatel battery and charger.