Fix: iPhone 7 Battery Draining Fast
I FIXED THE SAME PROBLEM ON BATTERY DRAIN ON MY iPHONE 7 PLUS! I had the same problem on my new iPhone 7 Plus 128gb phone running iOS 10.02 and here is how I fixed it!
First of all the way you know you have a problem (and also the way you know you have fixed the problem) is when you go to Settings>General>Battery and scroll all the way down and look at TIME SINCE LAST FALL CHARGE. If your usage time is the same as your standby time you know you have a problem and basically the iPhone is running continuously and not going into standby mode. THIS USUALLY IS BECAUSE AN APP ON YOUR PHONE IS MALFUNCTIONING AND YOUR PHONE IS RUNNING THE APP CONTINUOUSLY. You might get clues to this under the list of apps under BATTERY USAGE on same page but that wasn't helpful to me as it doesn't seem to show which app is running continuously.
Here is what I did to fix the problem and any one of these might fix it and I am not sure which one actually fixed it so here are things to try....
FIRST OF ALL MAKE A GOOD BACKUP BY CONNECTING YOUR iPHONE TO YOUR COMPUTER AND USING ITUNES.
1. If you are running Facebook on your phone then delete it and reinstall it as this app is one of the biggest culprits. Takes 5 minutes and might fix it.
2. Then do a soft reset....the way you do a soft reset on the iPhone 7 or 7 Plus is DIFFERENT THAN PREVIOUS iPHONES. Due to the new home button requiring power to work, Apple has changed the buttons used to force a restart. You now need to hold the wake andvolume down buttons at the same time. After a few seconds of holding in the buttons, the Apple logo will appear on your iPhone's display, indicating it has restarted, and you should be back in business. This takes only a minute or so..
3. I then "Reset all Settings" by going to Settings>General>Reset >Reset all Settings. AGAIN MAKE SURE YOU HAVE A GOOD UP TO DATE BACKUP DONE BEFORE YOU DO THIS. I didn't think this step did much and this doesn't erase content but you lose all your settings like wifi connections and passwords etc so i decided I didn't want to lose them all so then went to next step. This takes about 10 minutes.
4. I then connected my iPhone 7 Plus to my computer and restored my backup with iTunes. This takes an hour or two as I have a lot of apps and data.
5, I then went to Settings and scrolled down and turned off the "Allow Notifications" on each app that I could live without notifications. takes 10 minutes...
6. I then charged my computer fully and VOILA it was fixed and the way I know this is I went to Settings>General>Battery and scroll all the way down and look at TIME SINCE LAST FALL CHARGE and NOW THE STANDBY TIME IS MUCH HIGHER THAN THE USAGE TIME AND THE BATTERY IS WORKING FINE AND NOT DRAINING ANYMORE THAN NORMAL.
Sorry that i don't know exactly which step solved my problem but you can do this all in a couple of hours and it saved me from returning my iPhone! Maybe if others try these steps you could narrow it down and let people know which one worked. Reminder backup your iPhone to your computer before you do any of the major steps above. Hope this helps.
[Re-Titled by Host]
iOS 10.0.2