Hooking up the average ACR is simple: One wire goes to the positive terminal of the starting battery, one goes to the positive terminal of the house battery, and one goes to the boat’s common ground connection. When the relay contacts touch, both batteries are instantly wired in parallel (positive post to positive post and with a common negative post connection at the boat’s common ground).
It is important that both the starting and house battery circuits have the same operating voltage. Both circuits are most commonly 12 volts, but ACR models also are available for boats that have 24-volt starting and house battery systems. You cannot use these ACRs on fishing boats to combine a 12-volt starting battery with a 24- or 36-volt trolling-motor circuit. Accidentally applying 24 or 36 volts to equipment designed for 12 volts can be a dangerous and expensive way to learn how to operate a fire extinguisher.
Conventionally wired bass, walleye and bay fishing rigs can use a special type of ACR designed to combine all of a boat’s 12-volt batteries for charging, regardless of the combined series voltage in their multiple-battery, trolling-motor circuits. The difference between a fishing boat ACR and others can be determined with a quick glance at their wiring connections.
