Battery life decreased fastly
Why my iPhone battery life deceased fastly
Which iPhone and iOS version do you use? Since I do not know much about your iPhone and how fast and how much you discharged your battery, I am going to leave you with the following statement and question:
What is the Battery Health of your iPhone? Open Settings ➔ Battery ➔ Battery Health and let us know which percentage you see for Maximum Capacity. Also note what is written under Peak Performance. If your battery's Maximum Capacity shows a value of 80% or less than it has gone through its lifecycle and therefore should be replaced, according to Apple.
Axel F.