Instructions
Turn over your PSP in your hand so the screen is facing downwards. Press down the battery cover release button that is located on the lefthand edge of the unit.
Lift up the cover while keeping your finger pressed on the release button.
Lift out the battery underneath the cover using your fingernail or a screwdriver.
Locate the model number on the surface beneath where the battery is housed; you will be able to tell if your PSP is a 3001.