12V 140A Dual Battery Isolator Voltage Sensitive Relay (VSR) for Truck, RV, Marine, Boat, Camper & Off-Road Vehicle

Keep Your Auxiliary Battery Charged & Protect Your Main Starter Battery

Upgrade your vehicle or boat with this high-performance 12V 140A Dual Battery Isolator (VSR). Engineered for automatic power management, this Smart Voltage Sensitive Relay allows your alternator to charge two battery banks simultaneously while ensuring your main starting battery never runs flat. Ideal for RVs, campervans, marine boats, off-road trucks, and custom 12V dual-battery setups.

Key Features & Benefits

• Fully Automatic Dual Battery Management: Cut-in voltage at 13.3V and cut-out at 12.8V. Automatically combines batteries during charging and isolates them when resting or under heavy load.

• Smart LED Voltage Indicator: Equipped with a built-in LED indicator (LED ON = Charging/Combined, LED OFF = Isolated/Protection Mode) for real-time operation status monitoring.

• Zero Voltage Drop: Unlike traditional diode isolators, this VSR experiences no power loss, delivering full charging efficiency to your auxiliary deep-cycle battery.

• Heavy-Duty & Weather-Resistant: Built with a durable composite housing and weather-sealed design to withstand harsh off-road and marine environments.

• Compact & Easy Installation: Surface or panel mounting options with flexible wiring capabilities. Perfect for tight engine bays or battery storage compartments.

Specifications

• Continuous Current Rating: 140A

• Voltage Rating: 12V DC

• Cut-In Voltage: 13.3V

• Cut-Out Voltage: 12.8V

• Dimensions: 8 x 8 x 7 cm

• Net Weight: 235g

• Compatibility: Universal 12V dual battery systems (Lead-Acid / AGM / Gel)

Package Includes

• 1 x 12V 140A Voltage Sensitive Relay (VSR)

• 1 x Mounting Hardware Pack

• 1 x User Manual