I've had problems since version 5.1.3 with battery usage, even when my app is idle. I've just done a test with a blank app and my app, but have some interesting results.
If I run the blank app, and then use instruments to monitor Activity I can see it uses a few fractions of MS of CPU time every 10 seconds or so.
If I run up my real app, it shows it's using much more CPU time. If I pause the debugger, it shows no threads active except the Main thread, and Instruments continues to show CPU usage for my app.
Any ideas what this CPU usage could be, and could it be the cause of the battery drain? Basically, if I leave my app open at the login screen doing nothing with only a 3G connection it will die in 6 hours from full battery and I just don't know why as it's doing absolutely nothing. Wifi it lasts about twice as long, and obviously without my app running way way longer.
Any ideas on how I could find out what is ticking over and why?