Battery drain
NOT battery drain.... You need to learn to use your phone correctly.
Search these forums for tips on extending battery life....
No, not really. Im sure there are things that help, but that doesn't mean that 8.1 doesn't cause battery drain. I turned off NFC, turned down the brightness, and turned off Bluetooth but my battery drains a lot faster than it ever did. Im not streaming anything. I don't even have an app open right now. I talked on it for like 3 minutes this morning. It goes down almost 10% per hour.
8.1 doesn't cause battery drain!!!
Rogue apps, user's pattern of use. It's not the OS that causes 'battery drain'. I have owned WP devices since WP7 and have yet to have battery drain on any of them.
Use and charge your phone for a week or so and then see if the battery is better. It usually will be.
Failing that: Hard reset...