iOS 5 Upgrade: Massive Battery Drain and Crashing Phone App I upgraded to iOS 5 a few days ago. Although the installtion was a bit bumpy, everything completed successfully. However, since the upgrade, the following symptoms have occurred:


Phone battery life dropped dramatically. Locked handset warms up while the battery life drops by 30% per hour.
The Phone app closes as soon as it's opened. Calls can still be made via Contacts, but hanging up or using keypad tones is virtually impossible.


Actions Taken So Far:
1. Deactivated every location service, syncronisation, ping setting, and push notification I can find. No difference.
2. Deleted my iCloud account. No difference.
3. performed two complete restores. No difference.
3. Switched off Mobile Data. Success: battery life and Phone app restored! Although renders the 'smartphone' pretty useless.

Question:
Does anyone else have this combination of problems since upgrade, or have any suggestions to help me. I'm visiting the Apple Store at the weekend and will look forward to being reminded that my warranty is 6 days out of date.
Turn off Wi-Fi Sync.

I did it and voilá!

It seems that iPhone is constantly looking for an iTunes and tries to connect to it permanently. In fact If I had WI-FI Sync on, iPhone would appear on iTunes for a couple of seconds and then disappear.

To turn it off just plug your iPhone to your computer, open iTunes, click on your iPhone on the left bar and uncheck Wi-Fi Sync.

Good luck!