Over the past few weeks the battery on my iPhone 4 was completely drained twice a day after holding a charge for a couple of days when I first bought it last year. The main culprit appears to be the multi-tasking feature in iOS 4.3. Advice on the web began with checking the multi-tasking bar to see how many apps were open and running at the same time. Not even knowing that this existed or that the iOS 4.3 was keeping apps open, it should be no surprise that when I did look there were over 40 apps running. That's going to drain the batter pretty quickly.
In my research I found a number of ways to address battery performance issues on an iPhone and figured I may as well share them here as for those readers who have iPhones.
There were two very good articles plus comments that offered many ideas on how to address batter life issues in iPhone 4.
Disable "Ping" (Apple’s social networking/recommendation system)
* Launch Home Screen and go to Settings
* Select Enable Restrictions under settings
* Enter 4 digit pass code
* Scroll down to Ping settings and click on the switch to disable it.
It may save 2 hours of your iOS device.
Upon learning of the new MULTI-TASKING BAR I double clicked the home button and found about 40 APPS currently running. To fix this, turn off all the apps running in background: double click home button, hold an icon until the (-) symbol pops up and click on the (-) symbol for all the apps I do not want running in background.
* Turn the iPhone 4 off and then on again.
* Go to Setting > General > Reset > Reset Network Settings.
At least once per month, run the battery down and charge to full. For proper maintenance of a lithium-based battery, it’s important to keep the electrons in it moving occasionally. Be sure to go through at least one charge cycle per month.
Turn off Settings/General/Notifications, use the notification service for critical apps only.
Turn off Bluetooth, Find My iPhone, Dim Screen Brightness.
Some people experience a bug with iTunes on their Mac which can be fixed by uninstalling iTunes on Mac then re-installing it. In this case, the problem is iTunes updates, not the iPhone OS updates. NOTE: when it asks if you about removing files and folders associated with iTunes do not remove the files if you wish to keep your playlists and all that.
Restore iPhone (Back up the phone first first)