The SuperDroid Trekker requires 8 AA Batteries.� This package includes a charger with a plug end that connects to the OOPic II Expansion Card or the OOPic-R Expansion Card.� The AC plug can be used to power the Trekker.��If the batteries being used for the Trekker are not rechargeable, they must be unplugged when the Transformer is being used.� For rechargeable batteries follow this link.