A power conversion circuit includes a solar panel and a power converter. The solar panel is operable for providing electric power having an output voltage. The power converter coupled to the solar panel is capable of selectively operating in a charging mode and a powering mode. The power converter transfers the electric power from the solar panel to a power source and maintains the output voltage at a threshold voltage in the charging mode. The power converter delivers power from the power source to a load in the powering mode.