The battery drainage issue of a device running iOS 5 has been a major talking point over the months. The iPhone 4S, released in October, is no different from this problem. Apple has tried to fix the problem but has failed thus far. A fake Cydia tweak also previously claimed to solve this problem but nothing is certain at the moment.
However, here are eight temporary ways by which you can increase the battery life of your device.
1. One way to increase the device’s battery life is by disabling The Notifications and Apps. To do this, go to Settings-Notifications. Turn off the ones that don’t need to save the battery life.
2. You can also disable Ping. Just go to Settings-General-Restrictions-Enable Restrictions-select Ping and tap “OFF.”
3. Try and keep your Bluetooth off as it diminishes much of your battery life. To do this, go to Settings-General-Bluetooth (turn it off).
4. Apart from other applications, one of the main reasons for the diminishing battery life is the access to iCloud. To disable it, go to Settings-Locations Service. Here, just turn everything off.
5. Try re-booting the device.
6. You could also disable Diagnostic and Usage Reports to save battery. Just tap on Settings-General-About-Diagnostic and Usage (tap on don’t send).
7. Try resetting the Network setting. Just Tap on Settings-Reset-Reset Network Settings.
8. Delete your email accounts, reset the Network Settings and then re-add all the email accounts. Email accounts can be deleted by going to Settings-Mail, Contacts, Calendars-Account Name (tap to delete account). Next, to reset Network Settings, go to Settings-Reset-Reset Network Settings.
(Information from Jailbreakhow)