Do you have excessive battery drain of your iPhone / iPad after upgrading to IOS8?
Here is a solution?
Backup you device to your computer using iTunes and then restore your device from this backup.
Here are Directions:
1. Connect your iPhone / iPad to your computer via the syncing cable that came with your device and open iTunes.
(iTunes may automatically open if your iTunes settings are to open iTunes when device is connected to your computer)
2. Click on the icon of the iPhone / iPad on the top left of the screen to display the settings for your device
3. Select the Summary tab
4. Select "Back Up Now" button to backup your device to your computer
After backup is complete,
5. Select Restore Backup button - this will take about 3-5 minutes. Follow directions on screen.
After restore, your battery drainage problems should be fixed.