I get the feeling that after updating my WP to 8.1, the battery drains faster. Does anyone else get the same issue? is there a solution for this?
The new battery saver app introduced in 8.1 should show you battery use by app since you last rebooted the phone. On a phone that has just been turned on, it points a finger of blame at HERE Maps and People; obviously your battery usage will be different, and activities like chatting Cortana up will use a fair amount (after all, speech recognition isn't trivial, from a processing perspective), but this new app should let you identify if it's using a specific app that's causing the issue, if it's background tasks.
Of course, if you're actually using your phone more, I'd expect the battery to be used more :)
High battery drain after updating to WP 8.1 is not an isolated problem its all over the forums.
I'm pretty sure this is the problem with geofencing.
Geofencing is a new feature in Windows Phone 8.1. The phone keeps on checking your location continuously even though the app doesn't require it. Example IE, WhatsApp, etc. (pretty much any app). This is just like using Nokia Drive for 4 hours and your battery dies. Constant use of GPS reduces battery life and heats up the phone for no reason.
Whenever Geofencing is processing, the phone does it silently (the location icon on the top bar is not displayed - it is stated in location settings page of the phone)
How do i know its the problem with Geofencing?
Here is a little experiment that anybody can try (please don't mock this post if you haven't tried this out):
Turn off location and use your phone normally for a day and you'll notice the battery performance is like pre-update. And phone doesn't heat too.
It has been my experience that Windows Phone "always" has a rough first day or two after a major update or a restore. I've reset various phones of mine on a somewhat regular basis and the following day always seem to be an irregularly bad battery day.
If the trend continues, I would use various battery monitoring tools to track down the situation. It is also good to note that 8.1 now allows you to have more apps running in the background thus giving you more chance to use battery faster. It also gives you the tools to reign it back in too.
Perhaps it is related to this: http://forums.wpcentral.com/windows-phone-8-1-preview-developers/278439-must-read-lumia-920-owners-running-8-1-whatsapp.html
I have the exact same thing. Phone gets hot and battery drains within 20 hours with or without wifi. Whatsapp is always running even when battery saver is enabled. It should get an update asap. But I haven't seen a whatsapp update since FB bought them.
Here is a topic on MSDN about battery drain with the wp8.1 preview: http://social.msdn.microsoft.com/Forums/en-US/7252d7a5-affe-4e74-9d3c-9a55ccb5ca7b/battery-draining-faster-after-windowsphone-81-update?forum=winphoneosissues