A self-contained EVCS accessory is electrically engaged to an electric vehicle charging stations to derive one or more operational parameters during the electric vehicle charging process. The self-contained EVCS accessory includes a display unit that can display detailed information to the users regarding the charging process. The EVCS accessory uses its own built-in display unit and power supply to display the detailed information and requires no modification to the charging station. The detailed information, which may include the charging level, charging status, elapsed time, power transferred, cost of power, and the like, may be derived directly by the EVCS accessory or it may be obtained by the accessory from a predefined source of such information. Such an arrangement provides users with much more meaningful information about the charging process compared to the LEDs or light indicators of existing charging stations.