The battery life of a handset can vary greatly depending on how you use your device and your battery charging habits. If your device is running out of battery quickly， or takes a long time to start up (or even does not start up at all)， then you may need a replacement battery. Lenovo Battery BL197 - A820/A820T/S720/S720i/S750/S899T/A788T/868T/S868/S870/S889/S889/D780