Step-by-step DIY installation guide for a dual battery isolator
1.Plan Layout and Mount Components:Prerequisite.
Mount the secondary battery tray securely in your engine bay or vehicle body. Mount the Smart Battery Isolator (SBI/VSR) on a solid metal surface close to the main starter battery to keep the primary cable length short.
2.Route Positive Power Leads:High-current wiring.
Run a heavy-gauge positive cable (typically 6 AWG or thicker) from the main starter battery positive (+) terminal to the Input terminal of the isolator. Run a second matching positive cable from the isolator Output terminal to the secondary battery positive (+) terminal.
3.Install Inline Fuses:Safety protection.
Install an appropriate inline fuse or circuit breaker (e.g., 80A–100A, depending on cable gauge and isolator rating) on each positive cable run, placing them within 7 inches of each battery terminal.
4.Wire Ground Connections:Grounding.
Connect the thin black earth/ground wire from the isolator to a clean, bare metal chassis bolt or directly to the primary battery negative terminal. Connect the negative terminal of the secondary battery directly to a solid chassis ground point or the main battery negative terminal.
5.Verify and Test System State:Completion.
Reconnect the starter battery negative terminal. Measure voltage across the main battery with the engine off (~12.6V). Start the engine; once the alternator raises voltage above the cut-in threshold (~13.3V), verify that the LED on the isolator turns ON, confirming both batteries are linked and charging.