01. Turn off Background App Refresh
Go to Settings > General > Background App Refresh > Turn off Background App Refresh.
My brand new iPhone 7 plus batter life in standby mode drained too fast. My iPhone battery level was at 95%, when I went to bed and after 8 hours in standby mode, when i woke up in the morning, the battery level indicates at 75%. If there is someone who is having problem with the short standby battery life, try to turn off Background App Refresh. For me, Turning off this option solved the issue. After turning off the Background App Refresh option, Battery life was indicating at 93% from 95% for 8 hours in standby mode. I tested it several times and It only uses 2~3% when its ‘s standby mode.
02. Fetch Email
Your iPhone fetches emails regularly. But fetching emails too often is one of the reasons to drain battery life too fast. So let’s change fetching time. Please go to Setting > Mail > Accounts > Fetch New Data > Tab on Hourly.
03. Turn off Notifications
Let’s turn off the apps that’s not in use. Go to Settings > Notifications > Select the app that you wouldn’t get any notifications or that you are not using ofter. > Turn off Allow Notifications.
04. Reduce Screen Brightness (Turn off Auto Brightness)
I think most people know reducing screen brightness helps a lot to save a battery life. But for those who still don’t know about this, I share the instruction of adjusting screen brightness. Go to Settings > Display & Brightness > Turn off Auto Brightness > Adjust brightness using a finger tip.