Adding a second battery in your vehicle or boat enables you to power your electrics without flattening your main starter battery when the engine is off. Applications include, for example, 4WD’s with a 12V fridge/freezer, a boat with bright cabin lighting, or say a tradesperson’s van or ute with an inverter powering various power tools. This Voltage Sensitive Relay (VSR) kit provides everything you need to wire up your second battery, while handling the isolation during shut-off periods. It is provided with marine-grade hardware so it can be used on a boat or vehicle. Suitable for 12V systems with a continuous rating of 140A. All wiring hardware and instructions included. 
 
Note: additional black (negative) wire may be required for systems without chassis earth, such as fibreglass boats, depending on your installation.