Battery dying Android 7!!

Karll7

Hi!! After I updated to Android 7 and fast charging for some times the Battery it's not working well..
Now it's dying at 50/40%, this means I need to change it, just to calibrate or flash again with sptf will solve it??

First

I would try charging the phone for 24 hours.

Karll7

I'm already trying to calibrate naturally..and now I can see light in left  side of the screen..!!
but I think the only solution now will be a new battery..!!?