Hi All,
First off, I don't know if this will work for everyone, but it's worked for me so far.
Since updating to iOS5, I only got about 3-4 hours of battery before having to recharge, Charging to 100% before going to bed and then leaving it over night (with everything closed) I would wake up to a battery of 70+% with not actually using the phone.
So here's the steps I did to fix it for me, PLEASE BACKUP FIRST
Delete eMail Accounts, Reset Network Settings, Re-add eMail Accounts
1: Settings > Mail, Contacts, Calendars > Account Name > Delete Account
2: Settings > General > Reset > Reset Network Settings
3: Settings > General > About > Diagnostic & Usage > Don't Send
4: Settings > Notifications > Weather Widget > Notification Centre = OFF
5: Settings > Notifications > Stock Widget > Notification Centre = OFF
6: Restart iPhone
7: Re-add eMail Accounts & Re-connect to your WIFI etc
If this works for you, then good. I have no idea why it works though, if it doesn't, your going to have to wait for apple to release a fix.
My phone has been keeping a 100% charge all night now since doing the above :)
Useful, Paul, thanks.
Fortunately I don't seem to have any battery problems. Unplugged from overnight charge at 7:30am, some wifi and 3G data usage, 45 mins of music playing, a couple of text messages and a call and I'm currently at 91%.
I don't seem to have had any problems either. I always close all apps down and leave it on charge overnight. I usually also switch to Airplane mode, to stop any emails, etc. What is annoying with iOS5 is that there's no longer a global on/off switch for notifications.
Since I upgraded my phone I've kept it plugged into my PC so I've yet to see if this is an issue or not. I have noticed in the past that different versions of the iOS can have quite an effect on battery life.
1 cause of the battery drain seems to be a conflict between the old MobileMe account and the new iCloud account that gets created, quite a few people are saying that just removing these 2 accounts fix the issue as well..
I did the steps in my first post and have no battery drain issues at the moment..
I fully charged my phone, took it off charge at 11pm, I've used my phone quite a bit today and at the moment its at 93%, so a big improvement :) by now it would of been nearly dead.
This is what happened to me quite a few updates ago. Still not sure what fixed it, but I did a few restores over a few updates and that sorted it out.
So it retries a connection to the old account all the time (as it gets a "failure/retry" result)? A simple oversight which should be easy to fix really.