Using magnets to create perpetual motion?

Let's say I have permanent magnets set up in a sort of half sphere with the inside of the sphere pointing up and it laying flat on a table and then I have a ball with, let's say, half the radius of the half sphere. The ball has the same permanent charge as the half sphere. I place the ball over the half sphere. The ball and half sphere would repel each other and the ball would remain still and afloat. If I sent the ball on a spin, wouldn't it continue to spin ignoring air friction? I've always heard that perpetual motion is impossible on Earth, so what's wrong with this scenario? Would it even work? Would the ball's rotation slow down?