How to Wire a Relay and Why You Should Use Them

Best Practices for Dual Battery Setup

Proper Wiring: Use heavy-gauge cables and appropriate connectors to ensure efficient power transfer and minimize voltage drop.
Dual Battery Isolator: Consider using a True dual battery isolator to prevent one battery from draining the other, ensuring you always have a backup power source.
Regular Maintenance: Check fluid levels (for lead-acid batteries), clean terminals, and monitor the health of both batteries regularly.
Monitor Usage: Use a battery monitor to keep track of the charge status and usage of both batteries, helping you manage power consumption effectively.

Connect the Coil Terminals.

85 (Ground): Connect terminal 85 to the negative terminal of the power source.
86 (Trigger): Connect terminal 86 to the switch’s positive terminal or the control signal.

Connect the Power Terminals.

Terminal 30 (Common): Connect to a power source (the battery or power supply’s positive terminal).
87 (NO): Connect terminal 87 to the positive terminal of the device to be controlled.
87a (NC): If a 5-pin relay with the usually closed function is required, connect terminal 87a to the device that should be powered when the relay is turned off.