What would cause my Samsung tablet to constantly flicker and flash unless it's plugged in?

[AC Question]

I can now only use it when it's plugged in otherwise it's constantly flashing. I also get the overheating message and it shuts down on me.

 

[Rukbat]

That sounds like a bad battery. It will have to be replaced. (And drawing it down past 40% can cause it to go bad a lot faster than it should.)