About this item: [Wide Compatibility]--This battery isolator is compact and suitable for use in various vehicles, including ATVs, UTVs, boats, RVs, marine vehicles, trucks, and caravans. [Working Voltage]--The voltage sensitive relay (VSR) activates at 13.3 volts and deactivates at 12.8 volts, ensuring the primary battery remains charged and ready to start the vehicle. [Function]--When the engine is running, the VSR engages once the starting battery reaches 13.3 volts, and the LED indicator lights up. This connects both batteries, allowing them to charge simultaneously. When the engine is turned off and the voltage drops to 12.8 volts, the VSR automatically disconnects the batteries, preserving the main battery for the next engine start. [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: 80Amp Power stud: M6 copper screw nut Surge protection: Built-in 1. When the battery power 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 differences in display screens may cause slight variations between the color of the item in the photo and the actual product. Measurement may vary by +/- 1-3 cm.