My S3 Mini isnt staying on unless its on charge...

[LittleMissWolff]

My Samsung S3 mini keeps restarting every time I turn it on when its not on charge. Even when it is on charge it turns itself off. after a couple of hours.

 

[Titillating]

Sounds like it could be an issue with the battery. May need to replace it, if it isn't holding a charge correctly. Replacement batteries are pretty affordable and you should be able to find one for less than $10 in most cases.