Answer
Apr 30, 2026 - 09:57 AM
These protective devices are designed to protect an alternator's internal diodes from "load dump" events. These occur when the connection between the alternator and the battery is suddenly broken while the alternator is charging, causing a massive voltage spike that can instantly fry the alternator. Lithium batteries have an internal Battery Management System (BMS) that can instantly disconnect the battery to protect it from overcharging or high temperatures. If this happens while the engine is running, the alternator has nowhere to send its current, creating a spike. The Arco Alternator Shield or Balmar alternator protection module shorts this voltage to ground.
