Galaxy s8 battery discharge after 30%

[Android Central Question]

My phones battery works fine until it reduces from 100 to 30% and I get about 5hrs screen on time .But after 30% it reduces to 0% in less than 2 mins . Visited service centre twice ,they just reset my device and say that there is no problem with my device

 

[belodion]

A bad battery, perhaps.

 

[Dhanush Kumar1]

Here are my screenshots
https://drive.google.com/file/d/1WkfllNf4KNWHTw25GiecOIpqoND754mY/view?usp=drivesdk

https://drive.google.com/file/d/1syh70ZT7mJ7fwc4CkYPav657gOt24BxW/view?usp=drivesdk

 

[Dhanush Kumar1]

My phones battery was working fine but this problem raised few 4 months back and my phone is around year old.