How Do I Set Up a Dual Battery System for Camping?
Why Camping Needs More Than One Battery
Run a fridge overnight, charge a phone, power camp lighting or a portable fan, and your vehicle's single starter battery can flatten quickly — leaving you unable to start the vehicle the next morning. A dual battery system solves this by adding a second, dedicated auxiliary battery that powers your camping gear, completely isolated from the battery your engine relies on to start.
This guide covers how a dual battery system works, the key components involved, and what to consider before you install one.
How a Dual Battery System Works
The setup is simple in concept: your starter battery cranks the engine, and a second auxiliary battery — usually a deep cycle type designed for repeated charge and discharge cycles — runs your camping accessories. The two batteries are linked by a charging device that keeps the auxiliary battery topped up while driving, but isolates it from the starter battery when the engine is off, so your fridge running overnight can't leave you stranded.
DC-DC Chargers vs Basic Isolators
Older dual battery setups often used a simple voltage-sensing isolator, which works fine on older vehicles with basic alternators. Most modern 4WDs, however, run smart or variable-voltage alternators that don't always deliver a consistent charge, which is where a DC-DC charger earns its keep. A DC-DC charger manages the charging profile properly regardless of what the alternator is doing, and most also support solar input, so you can top up the auxiliary battery via a portable solar panel while camped.
Where to Mount the Battery
Auxiliary batteries are most commonly mounted under the bonnet alongside the starter battery, using a dedicated battery bracket, or in the canopy, tray or cargo area using a portable battery box. Which option suits you depends on available under-bonnet space and how much other gear you're already running up front.
For Hilux and Fortuner owners with room under the bonnet, the Front Runner battery bracket securely mounts a second 70A battery alongside the factory unit, using powder-coated steel construction built to handle vibration and heat.
Pajero diesel owners have a dedicated Front Runner bracket too, designed specifically for the engine bay layout on 2000-current models.
If under-bonnet space is tight, or you'd rather keep the auxiliary battery in the canopy or tray, the Front Runner 105A Battery Box mounts securely to any flat surface and keeps the battery protected from knocks and moisture.
An Alternative: Portable Power Stations
If you're not ready to commit to a permanent dual battery install, a portable power station is worth considering as a starting point or a simpler standalone option.
The EcoFlow Glacier combines a portable fridge freezer with a built-in power station, giving you fridge power and general device charging without any vehicle wiring at all — a handy option for weekend trips or as a backup to a permanent setup.
Getting the Install Right
Dual battery wiring carries real current and sits close to fuel lines and other vehicle systems, so it's worth having the install done or checked by an experienced auto electrician, particularly the fusing and cable sizing. A poorly wired system is a fire risk, not just an inconvenience if it fails.
Where This Fits in Your Build Order
If you're planning a full camping setup, sort your dual battery system before you invest in a fridge, lighting or other 12V accessories — there's no point buying gear you can't reliably power. Pair it with a DC-DC charger from the start rather than upgrading later, since retrofitting one after running a basic isolator is extra work for little benefit.
Ready to Set Up Your Dual Battery System?
Browse our Battery Box and Solar Systems range or explore battery boxes to suit your setup, and get in touch with our team if you're not sure which configuration suits your vehicle. Front Runner's full warranty terms are available on their official warranty page.