If you love camping, touring, or working off-grid, you probably already know the benefits of having a dual battery system—it keeps your fridge running, lights on, and devices charged without draining your starter battery. But what many DIYers don’t realise is that improper installation can damage your gear or blow a fuse—fast.
At All 12 Volt, we help Aussies build safe, reliable dual battery systems every day. This guide will walk you through how to install a dual battery system properly—without frying your gear or pulling your hair out.
A dual battery system separates your starter battery (vehicle) from your auxiliary battery (accessories). This allows you to:
Run fridges, lights, and chargers independently
Avoid flattening your starter battery
Stay off-grid longer with solar or DC-DC charging
✅ Deep Cycle Battery (AGM or Lithium)
✅ DC-DC Charger
✅ Battery Box or Tray Mount
✅ Heavy Duty Cables (correct gauge)
✅ Fuses or Circuit Breakers
✅ Anderson Plugs or Terminal Lugs
✅ Solar Panel (optional)
We recommend ZENOT dual battery kits—they’re built for Aussie conditions and easy to install.
Use a battery tray, cradle, or pre-wired battery box (ZENOT Extreme Box is ideal)
Ensure it’s bolted down and not sliding around the tray or canopy
Mount it close to the auxiliary battery, in a well-ventilated space
Some units also accept solar input—perfect for camp charging
Use appropriate cable gauge (e.g. 8AWG for up to 40A systems)
Route cables safely through conduit or split tubing
Fuse both ends (close to the power source and charger input)
Use quality lugs and crimp tools for solid connections
Connect charger output to battery terminals
Fuse the positive cable near the battery
Secure negative to chassis or battery terminal with clean ground
Use a regulated panel or connect through your DC-DC charger’s solar input
Use MC4 connectors and waterproof plugs
Keep panel close to the charger to minimise loss
Use a multimeter or battery monitor to confirm:
Vehicle charges the aux battery while running
Voltage increases when solar is connected
Check for warm cables or weak crimp points
Undersized cable (causes heat and fuse failure)
No fuse or incorrect fuse size
Poor grounding or loose terminals
Reversing polarity during installation
Overloading battery with too many accessories
Tip: Always install fuses within 15cm of power sources and keep spares on hand.
Use marine-grade cable and heat-shrink terminals
Avoid running cables near hot components or sharp edges
Label your wiring for easier troubleshooting
Include a voltage monitor to watch your system health
Don’t want to do the wiring yourself? Try our ZENOT Dual Battery Systems:
Pre-assembled with fuse protection
Built-in voltmeters, USBs, and Anderson outlets
Perfect for DIY installs, work utes, and touring rigs
Who does not love the outdoors and camping? It's a great adventure and opens up new destinations and often unexplored places. But you need to be well equipped with the safe and durable caravan and camping accessories for these outdoor activities. It is undoubtedly thrilling and exciting, but unless you take good care of what you need to do and what you should avoid, there's always a chance of an unpleasant experience. It pays to take sound advice from a 4WD specialist when going on a camping trip.