Just wanted to share this link.. not sure if anyone have seen this or try this yet?.. see below the detail i pulled from the internet.. http://www.iphonejailbreak.me/tweak-systems-power-profile-to-increase-battery-life-in-ios-5-x/ If youre a heavy iPhone user like me, your battery probably wont last more than a day. Check out this jailbreak tweak that might help squeeze out more juice from your battery. Just like a computers operating system, iOS also comes with power management that adjusts how much your device uses power. By editing the com.apple.SystemPowerProfileDefaults.plist file, you may be able to increase your battery life. I left my iPhone overnight at 85% battery power with WiFi, 3G and GPS turned on. By 8am the next day, it only consumed 2% of power. Not too bad, huh? Lets cut to the chase, heres how to do it: 1. Download DiskAid or i-FunBox. 2. Download one of these power profiles: see attachments Ultra power saving profile ultra_power_saving_mode.zip Medium power saving profile medium_power_saving_mode.zip Default power profile default_power_profile.zip 3. Launch DiskAid or i-FunBox and browse to the following folder location: /System/Library/CoreServices/powerd.bundle/ 4. Replace or overwrite the com.apple.SystemPowerProfileDefaults.plist with the one you just downloaded in step 2. 5. Reboot your device and youre done! If you like to revert to default power profile, simply use the default power profile plist file. I havent tried this on iOS 4.x yet but if you would like to try (at your own risk), the .pfile file is located at the following folder: /System/Library/SystemConfiguration/PowerManagement.bundle Good luck and share with everyone if this helps!