Battery Monitor App for Nokia Smartphones can be downloaded from Nokia Ovi Store. After downloading and installing the app, when you start the application you will be prompted with the following Security Warning message, tap Yes to continue with the application.
The first tab "Estimates" displays the battery time left for different activities such as Active use, Talk, Web browsing, Music Playback.
The second tab "Statistics" display the Overall energy distribution and the daily energy distribution. This would give a clear picture of the kind of activity that are being performed by you Nokia Phone.
For more information and for how to use guide tap the Info tab. This application has been developed by Nokia and VTT technical research centre of Finland. A quite useful to have it your Nokia Smartphones.