phone shuts down randomley

[Android Central Question]

30% charged but just turns off automaticlly why?

 

[belodion]

A bad battery perhaps. 30% is not random, though.

 

[Rukbat]

If it shuts off every time it reaches 30%, it could be a dendrite in the battery, which means that the battery has to be replaced (and dendrites aren't covered by the warranty).