Well, I hacked my PSP Phat by hardmodding my battery. Since I had only one battery, I had to buy another one. Apparently, I got a Slim version. From what I know, there are only two designs - one for all models, and one for Slim. I compared the two batteries and it looks like there's two things that are different - PSP Phat's current(current?) is 1800mAh and PSP Slim's is 1200mAh. Other than that, the right leg of PSP Slim battery is a little longer than PSP Phat's, which is not a really cofmortable fit, but that can be fixed. I stuck it in the PSP and it looks like it's working, since the battery icon is blinking, like it's charging. One other thing to mention is that my new battery could be fake. So...do you think it would work on my PSP Phat without problems?