I very recently shifted from iPhone 4 to my new Lumia 920 on AT&T. I have checked for similar threads but could not find a solution. I have installed Locksider+ app for updating lock screen automatically every one hour for which I observed a drain of approximate 10-15% per hour. I did not have this problem when I used 'My Lock Screen' app. Also how would you see the apps running in the background... Any task manager to kill unwanted tasks ??
PS: I m a new user to this platform and the forum...sorry if this seems to be a repeated qn