A motorized window treatment may be powered (e.g., entirely powered) from solar energy. The motorized window treatment may comprise a roller tube, a covering material extending from the roller tube to a bottom bar, and a motor drive unit configured to rotate the roller tube for adjusting a position of the covering material. The bottom bar may comprise at least one solar cell and an energy storage element electrically coupled to the solar cell. The motorized window treatment may comprise a dock, which may have a base portion electrically coupled the energy storage element of the motor drive unit. The bottom bar may be positioned adjacent to the base portion when the covering material is in a raised position, such that the energy storage element of the bottom bar may discharge through the base portion into an energy storage element of the motor drive unit.