How to Connect a Battery isolator Switch
We sell a lot of 12V battery isolator switches, both single and dual. We often get asked about additional details for the fitment hereof, so we decided to just give a brief summary of the steps and procedures for it.
Here’s a clear step-by-step guide:
What you’ll need:
- Battery isolator switch (rated for 12V, with enough amps for your system)
- Battery cables (same gauge as your existing positive battery cable)
- Wrench/spanner
- Cable lugs/terminals
Basic Wiring (Single Battery Setup):
- Turn off everything – Make sure ignition and electronics are off.
- Disconnect the battery – Remove the negative (-) terminal first for safety.
- Choose the location – Mount the isolator switch close to the battery, on a solid surface, and accessible.
- Cut the positive (+) cable – The isolator is always installed on the positive line, not the negative.
- Connect to switch:
- Battery side: Attach the cable coming from the battery positive terminal to the switch’s “Input” or “Battery” post.
- Load side: Attach the cable going to the starter/vehicle/fuse box to the switch’s “Output” or “Load” post.
- Reconnect the negative terminal to the battery.
- Test – Turn the switch ON → power flows normally. Switch OFF → everything cuts out.
For Dual Battery Systems (Jetskies, boats, Caravans, 4x4s):
- Use a 1-2-BOTH-OFF isolator switch:
- Battery 1 → Starter battery.
- Battery 2 → Auxiliary/house battery.
-
Switch lets you choose which battery to use, or both combined.
- Wire each battery’s positive cable to its respective switch post, then the common output to your load/starter.
⚠️ Safety Tips:
- Always fuse the line close to the battery.
- Use the same gauge cable as the original battery cable (usually 4–0 AWG for starters, lighter for auxiliaries).
- Don’t install it on the negative side unless specifically designed for that.
For more details on this installation process and options for your respective setup, feel free to contact us.
Check out the link HERE for the numerous Isolators switch options we have available.
