My Ipad 2 with OS 6.1.3 has issue with battery drain. What can I do to solve this?

Try turning off the following:

Settings>Mail, Contacts, Calendars>Push>OFF

Settings>Notifications>Mail>Gmail>Notification Center>OFF

Settings>Mail, Contacts, Calendars>Fetch New Data>Off

You may have to backup and do a restore.

Suggest you setup as new and try battery life again.

Before you Restore first try a Reset, it is quick and easy.

From the Home screen double tap the Home button to view the multitasking bar at the bottom. Tap and hold an app at the bottom till the icons wiggle with the minus ➖ button visible. Tap the ➖ button to close all apps then tap the Home button to get back to the Home page. Press and hold the Sleep button till you see the Slide to power off message and power it off. Once powered down completely press and hold the sleep button till the Apple icon appears.

Something may have gone amiss in the upgrade to iOS 6.1.3 on your device.

To correct this follow these steps:

1. Backup your device using iTunes or iCloud.
2. Use iTunes to completely restore your device as new.
3. Setup your device and monitor battery usage to see if it is normal. If not, you may have a hardware problem - if so, contact Apple support.
4. Restore your device from your backup above.
5. Check battery usage to confirm that it remains normal.