Specifications Parameter Specification Model VX5A1202 Series Xantrex VX5 (Automatic Source Selector Series) System Voltage 12 Volts DC (Designed for 12V nominal systems) Maximum Continuous Current 120 Amperes (A) Operating Principle Voltage-Sensing, Automatic. An internal control circuit monitors voltage to engage/disengage a high-current relay. Connection Threshold (Combine) Typically engages when the Priority Source voltage rises above approximately 13.3 volts for a set duration (e.g., 30 seconds). Disconnection Threshold (Isolate) Typically disengages when the Priority Source voltage falls below approximately 12.7 volts for a set duration. (Note: Exact thresholds are preset at the factory and may be adjustable in some models; refer to manual for specifics.) Internal Relay Type Heavy-duty, single-pole, normally open (NO) electromechanical relay. Voltage Drop Low voltage drop across the relay when closed (typically < 0.2V at rated current). Status Indicators LEDs: • Power (Green): Indicates the unit is powered. • Connected (Amber/Red): Illuminates when the internal relay is closed (sources are combined). Terminals Main Power Terminals: • PRIORITY (Input 1): Connection for the primary power source (e.g., engine alternator/starting battery). • AUXILIARY (Input 2): Connection for the secondary power source (e.g., house battery bank). • COMMON/LOAD (Output): Connection for the combined output or load. Control Terminals: Small-gauge wire terminals for remote status monitoring or override functions (if equipped). Wire Size Recommendation Use cable sized for 120A continuous current. Typically requires 2 AWG (35mm²) or larger copper cables, depending on run length. Mounting Surface mount with provided hardware. Must be mounted in a dry, well-ventilated location. Operating Temperature Typically -20°C to +60°C (-4°F to +140°F). Environmental Protection Designed for marine/RV environments. Often features a NEMA 3R or similar rated enclosure for protection against rain and splashing. Not fully submersible. Compliance Meets relevant standards for marine (ABYC) and mobile applications. May carry cULus, CE marks. Dimensions (Approx.) Varies by model. A typical unit for 120A might be roughly 150mm L x 100mm W x 60mm H (6" x 4" x 2.5"). Always verify with the official datasheet.