My PSP battery appears to not sit right in the PSP in one way, the battery door can't fit quite right. I can get the door to click into place, but then it is lifted at the side of the UMD door slightly. As I play games, the door lifts a little more, and a little more. Eventually, it hits a point where hitting the start button is enough to dislodge the battery ever so slightly, and shut off my PSP. I think this may be due to the battery being slightly enlarged, but would like a second opinion. If anybody wants pictures of what I'm talking about, I can provide them. Edit: Pictures - Warning: Spoilers inside!