Turning off background App Refresh is not what you need to do. It's there to help. Apps that run in the background do so with or without Background App Refresh being on. The problem is apps like Facebook that hang out in the background too long. Most apps don't stay in the background but a very short time. That's normal and doesn't use a lot of battery. Refresh was put in place by Apple when iOS 7 began. It's to help apps in the background to be more efficient. Turning it off only hurts. I have a small number of apps that stay in the background too long. I try to keep those swiped out of multitasking when I'm done with them. But I don't swipe all apps out. Not necessary. You probably only have 2 or 3 problem apps. What is your usage time?
Yesterday I only got 6 hours 45 minutes usage because of Facebooks nonsense. The worst part is I have to keep it on my phone because all my games are connected to it. It's seriously getting ridiculous. Before the most recent update from Facebook I was getting seven and a half hours to eight hours usage now this