Swis, your battery life is really not too bad. By your screen shot, there is definitely something running in the background but it could just be a normal process. I admit, my activity is only if I have the screen on and/or wifi on... otherwise no activity. But I have backgrounds sync disabled, all email set to manually pull and manually sync with no notification alerts except for text and calls. Facebook can also be a culprit, which I have that set the same (all manual with no notifications). And it could also be like rjeatkrconley, said... if playstore is auto updating your apps then it would be very difficult to know when that actually happens when it happens in the background.