About this item: [Wide Compatibility]--This battery isolator is compact and suitable for various applications including ATV, UTV, boats, RVs, marine vehicles, trucks, and caravans. [Working Voltage]--The Voltage Sensitive Relay (VSR) activates at 13.3 volts and disconnects at 12.8 volts, ensuring your primary battery remains charged and ready to start your vehicle. [Function]--When the engine is running, the VSR engages once the starting battery reaches 13.3 volts, and the LED indicator illuminates. This connects both batteries, allowing them to charge simultaneously. When the engine is turned off and voltage drops to 12.8 volts, the system automatically disconnects the batteries, preserving the main battery for the next startup. [Important Note]--When connecting accessories to the secondary battery, ensure they are fused within 0.98 feet of the battery. Product parameters: Type: 12V Voltage Sensitive Relay Continuous current: 80-100A Instantaneous current: 125A Current Consumption - Charging: 240mA Current Consumption - Standby: 8mA Detachment delay: 5-10 seconds Recommended Fuse: 80A Power stud: M6 copper screw nut Surge Protection: Built-in 1. When battery voltage is low, the auxiliary battery is disconnected to prioritize charging and operation of the main battery. 2. Once the main battery is fully charged, it automatically begins charging the auxiliary battery without affecting the power supply to electrical equipment. 3. Automatically disconnects the main and auxiliary batteries when not charging, preventing the main battery from being drained and ensuring reliable engine starts. Material: ABS Color: Black Package Contents: 1 x Battery Isolator Note: Light reflection and different display settings may cause slight variations in the color shown. Measurement error allowed is +/- 1-3 cm.