A mobile diagnostic imaging system includes a battery system and charging system. The battery system is located in the rotating portion of the imaging system, and includes one or more battery packs comprising electrochemical cells. Each battery pack includes a control circuit that controls the state of charge of each electrochemical cell, and implements a control scheme that causes the electrochemical cells to have a similar charge state. The battery system communicates with a charging system on the non-rotating portion to terminate charge when one or more of the electrochemical cells reach a full state of charge. The imaging system also includes a docking system that electrically connects the charging system to the battery system during charging and temporarily electrically disconnects the rotating and non-rotating portions during imaging, and a drive mechanism for rotating the rotating portion relative to the non-rotating portion.