Existing users, 
iPhone 3G battery draining too fast? Try this
Posted 13 July 2008 @ 3pm in Guides/How-Tos
The iPhone 3G has been shown to exhibit poorer battery life than its predecessor when persistently utilizing 3G connectivity. However, some have reported inordinately short battery life, which could have a variety of causes including:
- faulty battery indicator
- overactive Push mechanism
- application flaws
- hardware defects
If you think you’re suffering from unusually short battery life, try the following procedures:
Turn off Push The iPhone 3G’s Push functionality for Exchange and Mobile Me accounts can destroy battery life. Turn this option off in “Settings” and compare your new battery life to the old.
Force-quit applications If an application quits unexpectedly and you notice poor battery life afterward, relaunch the application then force-quit it by holding down the home button for several seconds. This can eliminate problematic or hung processes that might be draining the battery.
Reset iPhone In some cases, simply resetting the iPhone can resolve signal strength issues. Hold down the home and sleep buttons simultaneously until you see the white Apple logo, indicating that your iPhone has restarted.
This procedure can right a faulty battery indicator and eliminate applications that have hung or are otherwise improperly chewing battery.
Reset network settings Tap Settings, tap General, tap Reset, tap Reset Network Settings. This will cause your iPhone to restart, and will delete any stored Wi-Fi passwords as well as DNS settings and more. It can resolve signal strength issues in some cases.
Failing the above, peruse our special report on increasing battery life for first-generation iPhones — many of the same fixes may be applicable.
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6 Comments
Posted by unhappy_camper
17 July 2008 @ 12pm
Like many, I stood in line to get iPhone 3G on Friday. By mid-afternoon Saturday, I realized I had a SERIOUS battery issue. 1.5 hrs use (20 minutes phone, 1 hr music with the screen OFF, the rest web), and only 4.5 hrs standby COMPLETELY DRAINED the battery.
I’ll spare you the gory details and cut to the chase. Out of the box, my iPhone 3G had software version 2.0, rev 5A345, but found out that rev 5A347 was the current release. Clicking “update” in iTunes did nothing - “you’ve got the current version” message.
Not sure where it is on PC, but in Mac the iphone software is stored under Library/iTunes/iPhone Software Updates. If you dump the contents of that folder and then click “update”, iTunes will be forced to download the latest revision from Apple’s Servers.
Using this method to re-flash my iPhone 3G DRAMATICALLY increased battery life. Turning off 3G when I don’t NEED the high-speed data increased battery life even further. With these two simple changes, I went from 1.5hrs use/4.5 hrs standby all the way to 10.5hrs use/18 hrs standby and still didn’t reach low-battery warning (as before the change, most use was music with the screen off). If I need or want the high-speed data, it’s easy enough to go in and turn 3G back on.
If you’re suffering from inordinately short battery life with the iPhone 3G, check your firmware revision (Settings -> General -> About). If you don’t have 2.0 (5A347) or later, then you may want to try ugrading.
Posted by ktappe--2008
19 July 2008 @ 11am
I too am seeing less than 2 hours of battery life. And I have the 5A345 software. What I do not have is a /Library/iTunes/iPhone anything folder (nor an ~/Library/iTunes/iPhone folder either.) So the way I got 5A347 on there was to ensure the iPhone was synched and then clicked “Restore” in iTunes. It took a while to download the update, install it and restore the phone, but it’s all on there now. Time will tell if it worked.
Posted by backupgeek
21 July 2008 @ 11am
My original iPhone went from 2 full days per charge to less then a day.
I have had to turn off ALL push options for mail and calendar. I also turned off all location services.
Check the In Use time on your phone. If the phone thinks it has been in use for 8 hours since your last charge, then the push mail is probably keeping the phone “in use” draining he battery.
Posted by celeduc
22 August 2008 @ 1am
I came up with some more tips on how to solve the iPhone 3G energy crisis.
Posted by iphoneapp
22 September 2008 @ 5pm
Just bought one backup battery from WirelessInput.com, it works great. It can extend iPhone 3G battery to 140-150%, very compact size.
The link is: http://www.WirelessInput.com
Posted by nia_eor
23 September 2008 @ 7am
Try adding a yahoo, gmail etc: email account if you only have an exchange sync account configured.
The batter life went down to 2 hours after 2.1 update. Adding an additional smtp/imap email account to my iPhone stopped the exchange sync account from initializing the 3G connection to sync with exchange. This worked perfectly with exchange only before 2.1 update (work hone).