Don't use medium power saving mode because it active it's own run in background.So,tell me how this can save battery?Never! If u want to save battery or increase battery timing,you should use the device without power saving mode. And yes,when you do not use device for a some long time.You should keep the device at maximum power dmsaving mode because it changes all the setting,apply dark mode theme and only useful data available.
The medium power saving mode reduces CPU speed , reduces Brightness of screen and disables background refresh. of course its gonna run in the background because it is a part of Samsung UI. If you compare the medium power saving mode running to the amount of battery it saves , it's nothing. So , Medium power saving mode does work.
P.S: if you want to save more power enable *auto sleep apps. ¤ This feature puts the apps not in use for a period of 5-7 days to sleep and they don't use any data unless opened.
¤ Another feature you can use is Battery optimisation for apps that keep draining the battery fast. Go to Device Care -->Battery info ---> select the app that drains most of ur app then apply optimise battery usage.
Low Battery Dump option is used to Debug(identify and remove errors) Charging speeds and fast battery draining. The system creates a file of information for apps and services which may be causing Fast battery drain or preventing the phone from charging normally.
Basically if you are having issues with charging your phone or you notice your battery is draining too fast, Turn low battery dump ON.
