[Redgar]

Batteries have a limited lifetime. This means, after charging them an unknown numbers of time, they will end up loosing power and durability (like with mobile phones). If you have your battery in while having the AC addaptor and playing, the PSP will tend to work with the battery. But as it has the charger plugged, as soon as you play a little, it will start charging it. When its full again, it will start getting power from the battery, charging again and so on. Doing that is a waste. If you want your battery to last longer, dont charge it until its totally uncharged, and play with the AC addaptor as much as you can.

Also, dont try to charge the PSP without the battery. This mean, if you plug it is for charging or playing