This Dual Battery Kit from Matson will automatically isolate the starting battery from the auxiliary battery
The Matson Dual battery kit is designed to allow vehicles that require more power (for Fridges, extra lights etc.) to run a second battery without draining the power from the vehicles starting battery.
This product also comes with a 12-month warranty from Matson.
HOW THE DUAL BATTERY KIT WORKS
The Matson Dual Battery Kit is designed to allow the 4WD, caravan and boating enthusiast to run a second battery for all those power hungry outdoor accessories, without risking power drain from the vehicle’s starting battery. When installed in accordance with directions, the voltage sensitive relay will stay open when the engine is started, isolating the starting battery, until the charge rate reaches 13.3 volts at which time the voltage sensitive relay closes allowing both batteries to be charged. When the voltage of the cranking battery drops to 12.8 volts the relay isolates the two batteries leaving the cranking battery fully charged while the auxiliary battery continues to power the accessories.
The next time the vehicle’s engine is running, the starting battery is charged back up to 13.3 volts, at which time the VSR redirects the charge back to the auxiliary battery.