Xposed Module is required. It is a tool that reduces app's battery use by preventing them from using Android wakelocks. It treats apps in a more gentle way thus most of the apps' background functionality are kept but the battery consumption is largely reduced. Please be reminded that No Wakelock is not a process management tool like Greenify.
*How it works*
Android allows apps to use partial WAKE_LOCK to keep devices awake while screen is off. However, this mechanism is often abused as some Android developers introduced it into network related operations. As a matter of fact, network events will wake devices up automatically. Excess use of wakelocks is one of the top reasons why battery drains.
By using No Wakelock, you can have extended battery life without compromising on the functionality of apps.
*Types of Wakelocks*
Partial Wakelock: This is the wakelock that prevents your CPU from falling asleep while screen is off.
All Other Wakelocks: This is the wakelock that prevents your screen from turning off.
Sync Adapters: Sync Adapters can also keep devices awake. If you do not need synchronization, you can disable it.
Check https://www.linangran.com/?p=600 for more information.