iPhone OS 2.2.1: Battery Drain

Dozens of users have reported dramatically reduced battery life under iPhone OS 2.1.1. A sampling of iPhone Atlas readers:

• "Ever since I upgraded to 2.2.1 I have noticed that the battery life of my iPhone has significantly diminished. For example, my phone might have full/near-full battery charge at night, but in the morning it is down to 10%. Before the upgrade there would be almost no battery loss over night. I'm finding that I have to recharge it 2-3 times a day even with little use."
• "Now the battery indicator never goes down. This gives the impression that there is better battery life, but instead, the battery dies instantaneously without warning.
• "I notice my battery not lasting as long as before the update."

Potential fixes include:

Drain the battery completely Use your iPhone until the battery dies completely (indicated by a battery icon appearing on the screen when the sleep/wake button is pressed), then fully recharge the device. It appears that the full discharge may reset circuitry that prevents a full charge from occurring, despite iconic indication of a full charge.

Turn off location services It appears that the Maps application and some third-party applications that use GPS functionality fail to power down the necessary hardware components when they are no longer in use. Navigate to Settings > General > Location Services and turn these services off when you are not using Maps or another location-enabled app.

Turn off Push then restart The iPhone 3G's Push functionality for Exchange and Mobile Me accounts can destroy battery life. Turn this option off in "Settings" then restart your iPhone by powering it off then on.

Restore the iPhone with original settings Launch iTunes and select the second option in the "Version" section on the Summary page for your iPhone. This restore process will erase your iPhone software and data, including all settings, which can be restored later via iTunes.