Magsafe Charges for 5 minutes or so and stops...

I might have an idea of what is wrong but i dont know how to fix it. I went online to apples website and did exactly what the told me to do. I unplugged it for 60 seconds and plug it back in and it works. But it only works for another 5 minutes. So that doesnt really help me a whole lot. It said it might be a line noise issue. But i cant go changing anything inside the walls cuz i live on a military installation. So can i just not use my mac then? What do i need to do?

I had problems with my magsafe flickering from red to green, and the menubar flickering from calculating to charging. I called Applecare and they sent a new battery. Fixed it! Maybe your battery is bad?