Mercedes Benz

  EV Battery Capacity Degradation, Charging Handshake Failure, HV (High Voltage) Isolation Fault, BMS (Battery Management System) Error, On-Board Charger (OBC) Malfunction, Diagnostic Overview The System: EV battery health and charging involve three main stages: the charging station (EVSE) , the On-Board Charger (OBC) which converts AC to DC, and the Battery Management System (BMS) which protects the cells. The Problem: Problems usually fall into two categories: Physical Connectivity (won't start charging) or Chemical Health (driving range has dropped significantly). Common Failure Points Connector Pin Arcing: If the charging handle is pulled out frequently while active, or if dirt enters the port, the pins can develop "pitting." This creates resistance, causing the port to overheat and the car to throttle the charging speed to a crawl. On-Board Charger (OBC) Failure: If your car charges fine on a DC Fast Charger (Tesla Supercharger/Electrify America) but fails at...