Auto Charging Relay 12V - 140 AMPThe automatic charging relay (ACR) automatically manages battery charging to ensure maximum efficiency and protect your batteries.Features: Automatic battery management - connects batteries during charging and isolates them when the voltage drops Start Isolation (SI) - protects sensitive electronics during engine cranking by temporarily disconnecting house loads (indicated by a slow-flashing yellow LED) High-output support - compatible with alternators up to 120a A-A Dual-color LEDs - provide real-time battery status: Fault, Charging, Discharging, Combine, SI, and Override modes Under Voltage Lockout - prevents the relay from closing when battery voltage is too low (9.5V for 12V systems, 19V for 24V systems) Durable design - IP67 waterproof, ignition protected, safe for marine and RV applications Specifications: Continuous Rating: 120 Amps Intermittent Rating: 140 Amps Max Voltage: 48VDC Cable Size: 4/0 AWG Applications: Boats - dual battery systems (starter + house) Sailboats - navigation and lighting batteries Fishing boats - trolling motor and accessory battery protection