The Vigilant system includes the following main 4-5 components: Vigilant Monitor - Stores data, runs web-server, handles communications. (1) monitor per battery system. Vigilant Sensors - Measures cell/unit parameters. (1) per cell/unit, plus (1) per string. Connection Hardware - Physical connection to battery post. (2) clamps or (3) tab washers per cell/unit. Wiring Harnesses - Connects Vigilant sensor to battery connection hardware. (2) harnesses per cell/unit. Electrolyte Level Sensors (optional) - Measures electrolyte level, (1) per cell.