ASK ARB – which battery
is best for me?

Dear ARB,

Firstly, I’d like to congratulate you on a great read. As a member of a large roadside assist organisation for 25 years now, your mag leaves them in the DUST. I love the way you guys incorporate product information into an interesting read of a trip, which brings me to my question.

Having been a serious 4WDer in my younger years, we’re now looking at getting back into it with a Tvan which was featured in your Summer edition. Knowing that I will need to organise a power set up for this, can you advise on the best way for me to go about it as things with batteries have changed a lot since the days of simply installing an isolator solenoid? I see a lot of emphasis being put on the ‘Redarc’ system but I’m still unsure what type of battery would best suit, as the Tvan will have its own battery while also wanting an extra in our diesel 02 Prado (which has been the best 4×4) for when the van is not in tow.

Happy trails and kind regards,

Anthony Kellie

Dear Anthony,

For the auxiliary battery in your Prado, a cranking type battery is usually used, enabling you to have a backup for your main battery. Using a Redarc SBI12 as your battery isolator, you can jump start yourself should your main battery fail. Additionally, should you be running a winch on the Prado, the SBI12 can be used to provide power from your auxiliary battery to your main battery to assist under heavy winching situations. You will be best set up with a battery tray from ARB with a Century N70ZZ4WD battery.

In your Tvan, you will need a deep cycle battery. This will allow you to run loads such as lighting and a fridge for extended periods of time between charges. The size battery you can fit will depend on its mounting position in the Tvan.
Good options are the Century AGM 75A/Hr, or if you can fit, a Century AGM 100A/Hr. There are two great options for taking care of the battery in your Tvan. The Redarc BCDC1220 in-vehicle charger with battery isolation enables you to charge the Tvan battery while you drive. When the auxiliary battery is situated a large distance from the main battery, as in your application, the BCDC1220 is ideal as it overcomes voltage drop and provides the output voltage required to fully charge the auxiliary battery. It will charge your auxiliary battery with the specific profile required for correctly charging your AGM battery.

Alternatively, the BMS1215S2 battery management system with battery isolation will manage your auxiliary battery and utilise charging sources from AC, DC and solar panels. This product has all the advantages of the BCDC1220, with the addition of the ability to charge from mains power and the inbuilt MPPT solar regulator. The BMS1215S2 also has a comprehensive information display to keep you fully informed of your batteries’ state of charge and the load on the battery. From this information, it lets you know how long until your battery is fully charged and how long until it goes flat.

Either of these battery isolation charging system solutions will ensure your auxiliary battery is full of charge and ready to camp out just like you will be!

Stuart Peddle
(Sales & Customer Support Technician – Redarc Electronics Pty Ltd)