Just thought of this last night while I watched "The Avengers" on my ipad and noticed the battery draining while still plugged into the electrical outlet in my house. It just occurred to me about something else.
When iOS 10 first released, I noticed the immediate drop in battery power. Checking online only produced an article stating that there would be some drain on my device as it is natural for it to be reconfiguring all the apps on it. I said okay, fine. I'll wait. Still I waited and waited. Nothing. Three weeks past and I finally found this thread and it seems to fit (all but the Apple device).
But here is what I didn't include at the time. When that first update came, I was also experiencing something really weird. While reading stories in WATTPAD, a sudden voice startled me. It was British, male and was talking about how to make pancakes. This seemed extremely odd since this app is for reading and writing stories. At first I thought that Wattpad was now adding ads in their site and that this voice was from one of them. Then another hour later a newer voice came out. This time it was a woman's, still British, and this time talking about the differences in painter's pallets. I could only surmise that I was somehow picking up podcasts from somewhere because more of these audible pieces came ranging from 4 to 30 minutes every hour. Finally I presented Wattpad's developers with this issue. Of course they denied it was them due to them having no podcast of any kind like that or no ads that would be instructional in nature. Since there was zero visual media associated with it, I then assumed it was like prior upgrades on my ipad for which I recounted that even when exiting out of video, like YouTube, I could still hear the audible playing in the background (that one issue was of coursed fixed earlier on so it only lasted a couple of weeks at best).
So, I brought the issue to Apple via online (for which I believe I kept a copy of that online exchange) and even they denied that that weird podcast was their fault (believed to be their go to excuse for every problem as I'm seeing here). I don't know if it still is occurring since my solution to the problem was to just turn the volume down all the way while I'm reading.
Why I'm mentioning this is because I think there is a possible connection to it. Yes, I understand that whole refresher background thing and other apps running in the background... But I have been opting out of that feature since I first been aware of it back four or more years ago. There shouldn't have been anything running in the background unless I chose it to do so.
I think that despite our best efforts to run only the programs we find necessary, I think with this recent iOS update it has the power to ignore them (As seen in the settings for Background App Refresher being off despite apps like Wattpad and Wellsfargo indicating that they are in fact using the Background App Refresh) There is no way to currently disable that function for those certain apps.
That is why I believe the IOS 10 installment is draining the battery (and notable causing it to heat up to a point I am aware of it - so is my daughter on the newer ipad mini).
*To note* I‘m currently plugged into the outlet here at home and NOTHING is currently running (It's only turned on). It was at 100% plugged in when I started typing this comment and now at the end it's at 97%... WHILE IT’S STILL PLUGGED INTO THE WALL. And yes, I did in fact pay my electric bill.