A wireless pressure sensor for sensing pressure of a liquid in a tank includes a hermetically sealed housing, at least one sensor, at least one photocell array, at least one communication device, and at least one energy storage device. At least a portion of the hermetically sealed housing has a diaphragm. The at least one sensor within the hermetically sealed housing is configured to sense the pressure of the liquid. The at least one photocell array is configured to receive light and generate power from the light. The at least one communication device is configured to transmit data corresponding to the sensed pressure using wireless radio frequency signals. The at least one energy storage device is configured to store power generated by the at least one photocell array and provide power to the at least one sensor and the at least one communication device.