A long-duration power system configured for powering an electric load without the need for direct, wired connection to an outside power supply. The power system comprises a combination electromagnetic and solar power system. The system includes a rechargeable battery, photovoltaic modules, an electromagnetic (EM) receiver, an EM transmitter, and a power/battery management system. Primary electrical power is provided by the photovoltaic cells within the photovoltaic modules when the system is in light. Directed energy from the remote EM transmitter is configured to be aimed at the EM receiver, as needed, to augment the electricity produced by the photoelectric cells. The power/battery management system monitors the power system to ensure that the battery and the electric loads do not operate outside their safe limits. The power system may further include limit switches to prevent the power system from operating outside of safe limits.