smartphone wastes battery power

@muhammadsh29160 you have not told us how old your battery is or how long it last. If it lasts considerably less than what it did when you fist got the phone, replace the battery. If that does not resolve anything, you ill need to check all of your phone settings and set them to a battery saver profile. On your Oppo phone enable Super Power Saving Mode by going to Settings --> Battery --> Save power saving mode --> Super power saving mode.

To replace the battery use something like this video since iFixit does not yet have a specific guide for this.

While you work on your phone, take lots of pictures. Once you are done with it, take those pictures and create a guide for iFixit. That will help the next person that has a device with the same issues as you do. It's easy and fun to create these guides. https://ifixit.com/Guide/new The iFixit community will appreciate this.

Repair is War on Entropy!