How does Battery Sense work?

[kayb27]

Ok so I had tried switching Cortana's background tasks off and all the other apps on the list to no avail. I remembered that something similar happened with my 920 when I upgraded to WP8 and a lot of people had suggested draining the battery and turning off the phone for a while. I did the latter when battery was showing 40% and when I turned it back on it jumped to 67% (unplugged, duh). It's also a lot cooler than before. Might help some others out there.