The problem actually lies within the Wi-Fi performance profiles. If you did not install the 8.1 preview, stop reading this now. During the upgrade from 8.1 preview to RTM, the Wi-Fi profiles are not properly integrated. Rather than issuing a Windows Updates for this huge problem, Microsoft has instead released a quick fix for the problem. You can get it here:http://go.microsoft.com/?linkid=9841873
That wizard will quickly fix the problem. However, it you prefer to do this yourself, open command prompt as an admin and type (copy and paste) the following: powercfg -setdcvalueindex SCHEME_CURRENT 19cbb8fa-5279-450e-9fac-8a3d5fedd0c1 12bbebe6-58d6-4636-95bb-3217ef867c1a 3
Follow that command by entering powercfg -setactive scheme_current
My standby battery life is now back to about 2 or 3 days as it was with 8.0. I hope this helps
