So, a while ago, I just picked up my 3DS after it had been charging. It was going fine until I took out the adapter and it instantly shut off even though it was about fully charged. I plugged in the adapter again and turned it on, when I noticed that the 3D effect kept fluctuating. I was expecting to send it in to Nintendo when I decided to try one last thing: I took out the battery then put it back in and everything was working perfectly fine again. It's probably a rare bug but I thought I'd help people become aware of this if this ever happens to them.