I've had a few days with low battery last week and have spent a bit more time looking into the Usage menu. Right now I have 51 minutes of usage logged, even though I haven't used the phone since I pulled it from the charger. I haven't got any applications running in memory either. So this is quite strange. I also don't have any notifications on (not because of battery, but because of the hassle) or location services. What could be running in the background that counts as active time?