Macbook pro wont turn on unless plugged in charger

Hi!, Few weeks back i did reset my macbook pro 2015 retina display. It seemed fine but after a while in the same day or next day i updated the OS and i noticed that sometimes my macbook would turn off itself if not attended for couple of minutes and would not turn on if not plugged in even tho battery is sufficient and sometimes wont turn on without plugged in even tho im turning it on after hours being turn off. I tried resetting SMC, updating to macOS High sierra also but it wont work. If you can help me please, i'd be grateful. Thank you..