As android Nougat Has rolling out in market most of the users facing Battery drain issues Android Nougat 7.o Here I have Mentioned Some steps to avoid Fast Drain of battery.
Android 7.0 Nougat update has far too many issues that cause battery drain.The battery drain has been around from Android N developer preview 3 release, but Google has been ignoring it. The bug doesn’t let the device go into doze mode (to save battery) and manifests itself as Android OS or Android System in battery usage reports on the device.
How to Fix Battery Drain Issues Android Nougat 7.0
#1 Disable Ambient display:
Go to Settings » Display » turn Off Ambient display toggle.
#2 Disable Adaptive Brightness:
Go to Settings » Display » turn Off Adaptive brightness toggle.
Remove Body Sensors permission for Google Play services:
#1 Go to Settings » Apps » select All apps from the dropdown.
#2 Select Google Play services from the list of apps installed on your device.
#3 On the App info page for Google Play services, select Permissions.
#4 Turn Off Body Sensors permission for Google Play services.
If it gives you a warning, select “Deny anyway”.
#5 Reboot phone.
Also Try to check the Bluetooth Optimization is enabled most of the users face this problem in android Nougat.
I hope This Steps will increase your battery life by some minutes or hour