After updating to 6.0, I had a dramatic decrease in battery life. I updated to 6.1 on 1/28 thinking that they would sneak a fix in there since it was so widespread.
Now, after charging for 9 hours, the phone was unplugged on a table with nothing running and my battery was at 78% after 30 minutes. I've had to leave it plugged in whenever i'm not walking to keep it from dying.
Me too. And lot's of other people according to the internet. Don't Apple officials read the threads in this community and respond? So much for the Apple brand. (I am sure somewhere in Apple's endless community disclaimer it will say something like 'Apple is not committed to respond to bla.bla.bla...')
Same problem with my iPhone 4 upgrade to IOS 6.1 Phone is running hot and battery life is ~4 hours. Prior to IOS upgrade, I was only charging my phone 1-2 times per week. I tried turning off almost everything, but did not help.
I picked up some info on the web, stating that there was a bug with IOS and MS Exchange mail account.
1) Record MS exchange account information
2) Delete MS exchange mail account
3) Perform hard reset
4) Re-create the MS exchange account
Phone is back to normal, running cool again, battery back to normal!
Go to -> Settings -> General -> Reset -> RESET ALL SETTINGS - and confirm the changes
This will delete ALL previous settings (WON'T DELETE DATA), and after that you'll have to spend 10 minutes to adjust the new settings you want.
But that is a solution that adjusts the phone to the new iOS version, so it doesn't drain that much battery. Remember that and if you have any further problems with a next version - do the same again!!!
After doing this I had my iPhone 5 (iOS 6.1.2):
26 minutes usage
40 minutes standby
and only 2% battery loss, which I think is a normal level of loss!