A mobile filter for removing solid contaminants from water such as swimming pools. The mobile filter has a handle maneuvered chassis, a powered propeller housed in a propeller housing, which propeller propels water through a removable bag mesh filter installable on the propeller housing. A submersible battery pack is slidably coupled to the handle, and is readily removable therefrom. An electrical conductor spans and connects the submersible battery pack and the submersible electric motor.