Buying Guides

DCDC Chargers – The Ultimate Guide

DCDC Chargers

There’s nothing like heading off on a long journey away from home. If you’re a 4WD fan, the chances are that you’re in it for the off-grid experience. Of course, that doesn’t mean sacrificing on some campsite amenities. And if you’ve built, or are in the process of building, an outback-ready rig, then you’ve no doubt researched auxiliary batteries.   

But a dual-battery set-up alone doesn’t always guarantee peace of mind. The last thing you want is to run out of power because your auxiliary battery hasn’t been efficiently charged. That’s when a DCDC charger comes into play. This guide will help you discover all about DCDC chargers and what type of charger you will need.

Dual Battery Lithium Charger

What are DCDC Chargers

A DCDC charger is an electric power converter that turns a direct current (DC) source from one voltage level to the required level. It’ll smart-charge your 12V or 24V vehicle system in an effective, fast and safe manner. The power is taken from the alternator while the vehicle is running or — if you have one — the solar system. It will then convert this voltage to the correct level for your auxiliary and starter battery.

12v DCDC Charger Setup
24v DCDC charger setup

This charger will help store sufficient electricity for your starter battery, as well as the electrical accessories in your vehicle and even the caravan battery, if there is one. Installing a DCDC charger is an effective and efficient way of ensuring your auxiliary deep-cycle battery gets the charge it needs.

In addition, rather than waiting for you to reach your destination before erecting a solar panel, the DCDC charger will charge your batteries on the go, giving you 100% charge at the end of your drive. When you’re stationary, a solar equipped charger will then use the solar panel to charge the batteries without turning the engine on.

Solar inputs

Why A Smart Alternator Alone Isn’t Enough

Even if your vehicle is already fitted with a smart alternator that produces low voltage outputs, a DCDC charger will charge your batteries to their maximum capacity.

A smart alternator will use a range of parameters to decide the voltage output like speed, load, and the batteries’ current charge. While this will improve vehicle economy, the battery level may never reach full charge, which in turn reduces its performance, longevity and capacity.

Using a DCDC charger will solve these problems and save you a significant cost on battery maintenance long term.

The Technology Behind DCDC Chargers.

Chances are that no two dual battery set-ups are exactly the same, so you will need the right components for your vehicle to ensure you won’t have to replace parts down the line — a costly exercise.

The electronic conversion in any DCDC charger is the same. In the case of a REDARC BCDC1225D charger, the voltage rate can go up to 25amps which allows the batteries to charge faster.

These chargers temporarily store input energy from the alternator or solar panel and release power to the batteries at the required voltage. This switching conversion method is more power-efficient than linear voltage regulation that wastes unwanted energy by turning it into heat. Increasing the battery endurance, this switch-mode converter reduces the heat sinking needed.

The REDARC BCDC1225D charger features Maximum Power Point Tracking (MPPT) solar regulator that allows it to generate charge from both a solar panel and an alternator simultaneously. Thanks to the built-in Green Power Priority, the solar charger will be selected first, giving less load to the alternator, a helpful feature for vehicles fitted with intelligent alternators. The REDARC BCDC1225D is also equipped with new lithium charging profile allowing the unit to charge Gel, AGM, Calcium, Standard lead Acid and Lithium (LiFePo₄) batteries. REDARC also affirms that a battery bank size of 75-200AH is suitable for BCDC1225D chargers — for higher capacities, the REDARC BCDC1240D charger can be used.

These quality DCDC chargers have three stages being used, according to the level of charge the battery has. The first stage is the Boost, where maximum voltage is delivered to the battery as it is in the initial charging stage. Absorption is the second stage where the voltage delivery is continuous but maintained until the battery demands less than 4 amps. The third and last stage is known as Float, and at this stage, the voltage is comparatively lower and keeps the battery charge around 13.3 volts or fully charged. This 3-stage charging method will increase efficiency and battery life even while electronic accessories are running.

DCDC charging stages

To help the DCDC charger deliver the optimum level of charge, heavy-gauge cables can be used, and the charger can be installed as close to the auxiliary battery as possible. Mounting the charger somewhere with good airflow and close to the primary energy load also ensures the unit operates at its optimum.

DCDC Charger mounting

Consider these points when purchasing a DCDC charger

The DCDC charger you should buy depends on your vehicle battery’s chemistry, the capacity of the batteries, where you want to install it, and your budget. You can add more components to your set up and improve performance. For that, make sure you purchase the suitable parts to begin with, as replacing them would be more costly than adding. To discover the do’s and don’ts in the set-up, you should have test runs close to your home before heading out on long journeys.

Why the REDARC BCDC1225D is the best DCDC charger (in our opinion)

Best DCDC charger REDARC BCDC1225D

The REDARC BCDC1225D is an in-vehicle charger that is suitable for several types of batteries mentioned above. This charger is a variant of the award-winning BCDC dual range. They also state that it features REDARC’s smart start technology. This unit will make do with either standard or variable/smart alternators. REDARC confirms that their chargers feature award-winning technology, and they are independently verified and tested to ensure maximized battery life and proven 100% charge for your battery. They are built and tested in Australia under unique conditions and are proven to work under extreme heat in deserts up to 80⁰C and survive under deep water. Even when covered in dust and under harsh vibrations, this REDARC charger will deliver its purpose without any issue.

Towing a camper trailer or caravan and need a charger that can cope with the additional requirements of two auxiliary batteries? Consider the REDARC BCDC1240D 40A charger instead.

camper trailer dual battery setup

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