Whether you’re heading off on a day trip or a long adventure off-grid, chances are you will need some form of dual battery system. No matter what your charging requirements are, Fortunately Redarc has the right 12V system to suit your 4x4 vehicle.

To put it simply, your 4WD comes fitted with one start battery, which can power your accessories, but you will quickly drain that battery and have issues when wanting to start your vehicle if you make regular and prolonged use of those accessories.

This is when the dual battery set-up comes into place. Installing a secondary battery will give you around a day’s worth of power until it runs flat, while adding a battery charger to the setup will ensure that battery can be charged quickly whilst you are driving.

There are endless ways to customise the set-up in your vehicle to ensure it will perform how you want it to and where you want it to. And just like any purchase you make for your touring vehicle, it is important to get the right gear that will allow you to do what you want to do, as well as support the additional electrical accessories you want to run from your 4WD.

Smart/Dual Battery Isolators

Dual battery isolators or smart battery isolators have been used for years and offer an effective approach for using your vehicle’s alternator to charge the second battery whilst the vehicle is running. Its job is to also protect the start battery from going flat by isolating it from the secondary battery when the engine is turned off.

A battery isolator will recognise when the vehicle engine is running, and charge is going to the starting battery via the vehicle’s alternator. 

A good analogy for this is to think of the battery isolator as a tap between the batteries and the alternator as a pump feeding the start battery. Once the pump (alternator) fills the start battery to a point (13.2v) the isolator detects this and turns on, allowing the feed going into the first battery to pass onto the secondary battery. Therefore, the pump feeds both batteries at the same time.

This type of set-up is recommended for vehicles that have a fixed vehicle alternator, and can be installed under the bonnet if you’re on a budget. 

DC-DC Battery Chargers

Generally, an in-vehicle battery charger such as the REDARC BCDC charger, is going to offer more flexibility for your dual battery setup. Not only in terms of correct charging for your specific battery, but also suitability for different alternator types, installation location, and amp size. 

The REDARC BCDC battery charger is designed to work with any type of alternator and to effectively charge a secondary battery to 100 percent, prolonged its life. It applies the correct voltage level to achieve a full state of charge, while controlling the amount of current flowing into the battery, so that it doesn’t charge too quickly and cause unwanted damage. In terms of efficiency, this is one of the best car battery chargers you can buy. 

It also serves as a solar regulator so you can charge your secondary battery with solar panels and it will select the green source of power first to minimise the load on your alternator. 

An in-vehicle battery charger may also be necessary when you have to install the secondary battery away from the alternator due to space restrictions under bonnet, as it can overcome voltage drop from long distances. 

Finding the correct size dual battery charger

 If you are thinking of going down the DC-DC charger route, then also consider the amps required. 

As a general rule, battery bank sizes of 75-200AH require a 25-amp dual battery charger and then for higher capacity needs, a 40-amp or 50-amp dual battery charger is recommended. This is important as excessive current flow into a battery can impact it in a manner of ways, the worst of which can be the degradation of battery service life and capacity. REDARC offer 25, 40 and 50-amp options in the BCDC chargers range. 

Battery Management Systems

If you really want to get the most out of your dual battery setup, then the crème de la crème of car battery chargers would have to be a battery management system such as the REDARC Manager30.

It combines six products in one and offers a variety of features unlike anything else in the market:

• DC-DC battery charger.
• 240V charger.
• Battery isolator
• Load disconnect controller.
• MPPT solar regulator.
• Remote monitor.

The new Manager30 lets you see how your battery is charging and monitor where the charge is coming from – now with new display screen and mobile app.

For more information on the REDARC range of off-grid power solutions, visit www.redarcelectronic.co.nz