In this paper, we propose an electric power management system for delivering power to home appliances with mobile robots. With our system, the user places an appliance without power cables freely within the home, and a robot provides the appliance with the electric power required for its operation. In addition to providing explanations of a usage scenario and a theoretical analysis, we demonstrate a prototype implementation. The robot of the prototype autonomously locates the target appliance, transfers its battery power to the appliance, and returns to the home position to recharge its battery. The validation study showed our proof-of-concept prototype worked as expected by the theory.