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Where To Install Your Dual Battery Setup

Where To Install Your Dual Battery Setup

So, you’ve bought a new 4WD and are keen to get it off grid ready but aren’t quite sure where to install your 12V system. We’ve put together a bit of a guide on the different install locations and which products and vehicles they’re best suited to.   






To determine if you can install your dual battery system under the bonnet, you’ll need to make sure your vehicle has enough under bonnet space for multiple batteries. This setup often works better in older vehicles which have the space in the engine bay to accommodate a second battery, or in more typical 4x4 vehicles.


What vehicles?


Typical vehicles that have this type of dual battery installation include; Toyota Landcruiser, Toyota Hilux, Isuzu D-Max, Mitsubishi Triton, and Nissan Patrol.

REDARC has a range of vehicle specific mounting brackets for our range of DC-DC battery chargers to help simplify installation for those keen to DIY.


dual battery under bonnet


What’s the benefit?


A huge benefit of engine bay mounting is the saving of space within the cabin or canopy of your vehicle. If space is a hot commodity in your vehicle you might not have room to mount a secondary battery and charger, so hiding it all away under the bonnet is often a good idea. It can also be a handy way to hide the whole setup if you don’t particularly like the look of it out in the open, while keeping it accessible to run solar via an Anderson plug from your charger under the bonnet.


What products?


If you’re looking to install your 12V system under the bonnet, you’ll need to choose products that are built to withstand the engine heat. For auxiliary batteries, you’ll want to choose either a standard lead acid, calcium, or lead crystal battery as these chemistries can take the engine heat with no issues.

If you’re looking for a simple solution to not draining your starter battery while you run your accessories from your auxiliary battery, the SmartStart Battery Isolator can be mounted under the bonnet and will prevent your start battery from going flat.

To take your setup up a level and keep your batteries charged to 100%, you’ll need an in-vehicle battery charger that can be mounted under the bonnet. The BCDC charger range has been designed to withstand engine heat while effectively charging your auxiliary batteries. It does pay to note that while the BCDC can be mounted in the engine bay, it is recommended to install it away from direct engine heat. To learn more about ideal BCDC mounting locations check out the do’s and don’ts of BCDC mounting.

Combining the SBI and BCDC to your dual battery setup gives you the freedom to jump start your vehicle if you ever find yourself in trouble.


bcdc mounted under bonnet






For many people a traditional 4x4 is the only way to go when deciding on their next touring rig. They have plenty of space, and everything is accessible within the cab. For bigger families having the option of a third row of seats can also be handy.


What vehicles?


Vehicles that don’t have engine bay space, people who don’t want to lose vital boot space, or when there’s less reliance to carry extra passengers or people that pack heavy in the back of the car.

Popular 4x4s include the Mitsubishi Pajero Sport, Isuzu MU-X, Ford Everest, and Toyota Prado and Fortuner.


What’s the benefit?


For many people the space available is the reason they choose a typical 4x4. Having everything inside the cabin, there’s plenty of space for the family and all your gear. Without a barrier between the cab and the boot, all your accessories are easily accessible within the vehicle. Many traditional 4WDs also have the space to fit and install your accessories into the side panels of the boot, hiding them away and saving space.

Another of the benefits of a traditional 4x4 is the versatility. With so much space there is the option to install your off-grid power setup in several different places. From behind the backseat to in the boot to fitted in the side panels. But one thing to remember is that you need to place your auxiliary battery as close to your charger as possible, to ensure there is no impact on charge capability or voltage drop.


12v installed behind seat


What products?


While some traditional 4WDs come with a dual battery system fitted under the bonnet these are often wired in parallel which is not what 4WDers want. Having an efficient secondary battery means you can stay off grid for as long as you like without worrying about running out of power. As you’re not mounting under the bonnet you’ve got plenty of freedom when choosing a battery chemistry. For the most efficient battery choice lithium is the way to go.

Cabin installs also give you plenty of freedom when it comes to product choice as you’re not limited to products that can withstand engine bay heat. While you can mount a BCDC in your vehicle, for an all in one solution to battery management, the Manager30 is the perfect solution. Able to be mounted inside the vehicle, it incorporates AC, DC, and Solar inputs. The benefit of a Manager30 over a BCDC for an install is if you’re planning to spend a lot of time camped up at powered sites you can plug in and charge your batteries from mains power.

If you’re planning on spending an extended amount of time off grid and run multiple onboard devices having a RedVision Vehicle Management System installed in your canopy means you can easily control all your devices at the touch of a button or through the smartphone app.






Dual cabs are quickly becoming the vehicle of choice for many 4WDers. This can often be put down to a few things including both their size and flexibility as well as their safety and luxury features that were previously only available in high end SUVs.


What vehicles?


Some of the most popular dual cabs out there include the Ford Ranger, Toyota Hilux, Volkswagen Amarok, Holden Colorado, Isuzu D-MAX, and Mazda BT-50.


REDARC 12v canopy install


What’s the benefit?


A huge benefit of a canopy install is that your setup takes up no space within the cab of your 4WD. This means that you don’t have to worry about removing seats or leaving gear home to make room for it. Another benefit of a dual cab is their availability, with so many available there’s sure to be a model with all the features you’re looking for.


What products?


Most dual cab utes are built with just one starting battery so you will need to install a second battery for auxiliary purposes, to increase capacity, and allow loads to be run when the vehicle is off. Installing in the canopy opens your battery chemistry options up as you’re not limited by battery chemistries that can withstand engine heat. This means that a canopy install is perfect for a lithium battery. Like a traditional 4x4, you can run either a BCDC or Manager30 in your canopy to keep your batteries charged.

If you’re taking the family, having the ability to run all the accessories from home is important. For this you’ll want to run a Pure Sine Wave inverter. An inverter allows you to plug in and power all your accessories that run on 240V mains power. This means that blenders, coffee machines and all the creature comforts of home can be powered.


12V inverter install


REDARC has a range of battery charging kits and off-grid solar kits available to take the hassle out of building a 12v system. Are you ready to tackle your own off grid build? Take a look behind our build to find out how we turned this stock Hilux into an off grid 12V powerhouse.


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