In which condition is my mobile battery

[Android Central Question]

My smartphone automatically switched off at battery bellow 30% charge.after that login phone again,it become very hot and battery reduce speedly.

 

[B. Diddy]

Welcome to Android Central! Which phone? The battery is probably failing. If the battery is removable, try a new one.

 

[Rukbat]

And if you keep running it down way below 30%, it's going to fail quickly even if you replace it with a good one. Lithium batteries are not deep discharge batteries. (We use them because they're the lightest batteries we can make.)