Using a Hardkorr battery box with voltage-sensitive relay (VSR) is the simplest way to create a dual battery setup in your vehicle. The VSR acts as an isolator, allowing the auxiliary battery (inside the box) to charge directly from the crank battery while the car is running.
All Hardkorr products are manufactured using the highest quality materials. We are confident that they are the most durable in the market and will give you many years of reliable service. We stand behind this product with a comprehensive 2-year Australian warranty and a 30-day money back guarantee.