Finally SOLVED my standby battery drain problem! I have no idea if this will work for others, but I've been following this forum for awhile now and everything I've tried over the past 3 weeks were utterly unhelpful, but this one thing totally totally solved my problem. I share it in the event it might help others. Again I can't of course say that this will work for anyone, but it totally totally utterly saved my battery drain problem and the solution has nothing to do with turning off tons of features like so many are saying. What a crazy advise people are giving. They are basically saying turn off everhing that is good about the phone and useful and maybe you will get better battery life. Utter rubbish. We should not have to not use any of the helpful features of our phones to simply get halfway decent battery life. So let me list the problem I was having. Then what I tried to fix it. And ultimately what ended up totally working.
Problem:
After extensive testing I came to the conclusion that the main issue with my iPhone 7 Plus 256GB was with the strange standby draining time. I think this is the key the battery drain issue. The standby drain time is what is causing the massively short battery life for many (for me certainly), but again I don't know if that is true for everyone. I'm just sharing what I withnessd with my own phone.
I would put the phone on do not disturb and let it sit for 10 hours each day during the test (I used another phone during this testing). I did this test with iso 10.0.1, 10.0.2, 10.0.3, and 10.1. Every since version ended up draining about 2% every hour so afte 10 hours of zero actively (no screen turn on even because it was on DND) my phone would be at 80%. This was utterly repeatable each and every time. Sometime it would be 15% sometimes 18% and sometimes 20% but it was in that range per 9-10 hours of standby with zero use of the phone. My useage time showed that no apps were during the battery, because useable would be like 9min after 10 hours.
Things I tied to help fix this (not in the order listed, but I did at one point tried each things and tested again). This took over 3 weeks to do while I used my other phone. I would make a change to fix it and then leave it in DND for 10 hours while I went to work.
1. Reset all settings.
2. Reset just network settings
3. Turned on Reduce Battery mode
4. Turned off ALL locations service
5. Turned on Reduce motion
6. Turned off all PUSH
7. Turned off ALL notification
8. DFU restore and backup from old backup
9. DFU restore and setup as new phone
10. DFU restore and setup as new phone and didn't install ANY apps at all
10. Turned off background refresh
11. Did all of the above at the same time as well
12. Did this for every version of iOS 10 from 10.0.1 (what my phone first came with) to 10.1 current.
Result: NONE of those steps done alone or together at once fixed the standby drain problem for me AT ALL.
What actually worked:
I found out recently that I had the iPhone 7 Plus At&t intel modem version and have been wanting to switch to Verizon. It was at this point that I was made aware that I could not do that with my phone. I did not know this when I bought it. It was never told to me and Apple does not state this very clearly or easy to find.
So after talking with Apple they agreed (they were really pleasant actually and I didn't get emotional or upset...I just simply said it was the right thing for them to replace my phon with sim free phone...and they agreed without argument at all) to change my phone to a sim free phone.
So I got a sim free iPhone 7 Plus a few days ago and after getting it this is what I did and it fixed everything.
1. I backup my current At&t iPhone 7 plus 256GB to icloud and iTunes encrypted backup.
2. I took my phone to apple.
3. They took my sim out and put in in a new retail boxed sim free iPhone 7 plus 256GB
4. I came home and did DFU restore to ios 10.1 current version
5. Restored from iCloud backup
6. Turned ON ALL settings, including hey siri, background refresh, all location service, push, icloud service, and iCloud drive, etc. I turned everything on full blast
7. The backup automatically reinstalled all 87 apps including facebook and messenger
8. Let me phone sit for 24 hours on chargers and then I restarted the phone and then let sit again another 2 hours while charging.
The final result:
I took off charge and put it on DND and let it sit for 10 hours (I used a timer). When I went to check my useage time was 4 min and my standby said 10 hours and get this.....
BATTERY DRAIN was down to 99%!!!!
I repeated this after a days use and next day same story. Only 1% drops after 10 hours of standby!
I have no idea if it was the sim free version with the non-intel modem or not, but this totally fixed my drain problem! This is with everyone turned on with no features off! This was the only thing that fixed my problem. I have no idea if this will work for anyone else or help everyone else (I understand that not everyone could be having the same issues as mine was so our solution would be different), but this totally fixed it for me. I am getting incredible useable time over 13 hours usage and over 27 hours or more standby before I have to charge!
I hope this was helpful.
