Some users have reported poor battery life from iPhones, iPads or iPod touches after the update to iOS 4.2.1. There are a number of potential fixes for this issue:
Fixes
Restore, but not from a backup (use as a last resort). This fix has proven successful for the most users thus far. It appears that bad holdover data from iPhone backups can cause excessive battery use. Restoring as a new phone will delete contacts and other data, but may resolve this problem. To do so, connect your iPhone or iPod touch to your computer, click “Restore” in iTunes, then choose “setup as new phone.” You can then re-sync your media and other data.
Check Internet tethering. Some reports indicate that the iPhone may be persistently attempting to establish a tethering connection, thereby draining the battery. Navigate to Settings > General > Network and tap Internet Tethering, then tap “cancel” if you it is trying to connect, or turn off tethering altogether. You may need to turn Wi-Fi off then back on to stop the tethering connection attempts.
Bad apps to blame? Anecdotal evidence suggests that apps incompatible with iOS 4.2.1 or otherwise problematic under the new release can cause battery drain issues. Backup your iPhone or iPad in iTunes, then delete apps from the device in groups (you can always sync them back from iTunes later). After each group, restart your device and check for the battery drain problem. Via this method, you can isolate the problematic app and remove it permanently.
Also, make sure all apps are up to date; developers have released a flurry of iOS 4.2.1-compatible app editions in the past few days.
Turn off Push. Navigate to Settings > Mail, Contacts, Calendars and tap “Fetch New Data.” Turn off Push.
Calibrate the battery. Fully charge your iPhone or iPad then allow it to drain until completely empty (device powers off on its own and displays a spinning progress indicator). Then recharge your device and check for excessive battery drain.
Close open Safari windows. One iOS application that consumes memory and processor time (and therefore battery life) in the background is Safari. Close all unused windows in the application by pressing the page switch button in the lower right portion of the screen then clicking the X at the top left of each page. See this page for screenshots.
Obsessed with tech since the early arrival of A/UX on Apple, Sudz (SK) is responsible for the editorial direction of AppleToolBox. He is based out of Los Angeles, CA.
Sudz specializes in covering all things macOS, having reviewed dozens of OS X and macOS developments over the years.
In a former life, Sudz worked helping Fortune 100 companies with their technology and business transformation aspirations.
i have turned everything of notofication wifi gps 3g data push mail app runing and i closed it by multitasking bar and my iphone 3G iOs 4.2.1 BB 5.13.4 last only a day with charging it’s weird please help
The culprit for me was the MAIL app: completely turning off my mail account solved this. I check my mails on another machine 🙁
A corrupted exchange file may be the cause, I believe the restore process from Apple do so by forcing you to re-create the account from scratch, getting rid of the bad file.
please help, if im lucky my iphone 4 lasts for 2h, 30 minutes of usage and i am always closing my apps! i tried a complete dfu restore (not from backup) and i reset my network settings. i updated to ios 4.3.1 and it is still draining battery. i did a hard reset, i turned off ping and all push email and notifications. i rarely switch on 3g and mobile data and wifi is only switched on when i am using it. please help and thank you in advance.
my iphone4 4.2.1 battery stats:
usage : 5h, 52minutes
standby : 20h, 31minutes
my iphone hardly lasts for one day, making me carry the charger wherever i go. what might be the problem ? i have done everything that was mentioned above.
Do help !
i don’t have that app but my battery is still doing it…
The battery drain problem after installing iOS 4.2.1 is
“Find My iPhone”. (it keeps running on the background, thus drain
the battery even if you don’t use the machine). Just do these and
the battery problem will be fixed : 1. Turn OFF “Find My iPhone”
(setting->email->MobileMe) 2. Install this profile
from the iPhone : http://support.apple.com/kb/TS3398