I had this issue for a while now and fixed it for about 2 months or so and now it is back. I found several threads with people having the exact same issue caused by Steam and/or Oculus drivers and the Nvidia Wireless Controller Service. I terminated steam and the service and it worked. Now it doesn't although none of the above services/programs are running and I don't have an oculus, so that's not an issue.
I am desperate to get my controller working again, it is really annoying. And it is definitely not an issue with old drivers or the battery, because 3 days ago it worked fine and it is still working after a restart of my computer. But after the restart it disconnects after 20 seconds or so and after that I can only reconnect for 1 sec. With a USB cable it works fine, but I haven't bought the Elite Controller for that. It must have to do with MS Updates, because I deleted the last updates of my NVidia Card and I restored windows to the last restore point before the issue came up again, didn't work.
Please have a look into this :(