DC Battery Chargers

Home of 12 Volt offers an extensive range of DC chargers compatible with all chemistry batteries. We offer an advanced 'quick connect' option, featuring Anderson connectors for a fully portable unit. We also offer battery boxes with built-in DC chargers — an excellent option for portable dual battery systems!

Understanding DC to DC Chargers

Here at Home of 12 Volt, we attempt to educate you on whether you do, in fact, need a DC charger and where best to spend your money for the best 'bang for buck'. Put simply, a DC to DC battery charger is an 'in-vehicle battery charger'. It has the ability to convert a low-voltage from the vehicle (as little as 9 Volts) and increase it to produce an output voltage to your auxiliary battery, suitable to the battery chemistry you are charging. The DC charger is designed to run through several charging cycles, analyzing the battery and performing a soft or bulk charge depending on the battery chemistry.

Do You Need A DC to DC Battery Charger?

It is common for vehicles dated 2016 or later, that the alternator output voltage is usually very low. This low voltage affects the ability to charge secondary battery systems within the vehicle.

It basically comes down to the changing emission laws on the market. It has been found that when vehicles are not running at full capacity, their emissions are less. If the emissions are lower, vehicle manufacturers are given a big green tick of approval for releasing their new model vehicles, and they hit the market with what we all know as a 'variable alternator / or smart alternator'. 

What is a Smart Alternator, And How Do You Know If You Have One?

It's pretty safe to say that the majority of vehicles manufactured in 2017 or later would have a smart alternator of some sort. This means that the vehicle was manufactured within a time in which it was made to comply with specific emission requirements.

The easiest way to explain how a smart alternator works is as follows:

When the vehicle is initially turned on, the alternator will run at full output, providing a good, high voltage through to charge your starter battery and provide power to all accessory connections throughout the car. After a few minutes, the starter battery will reach a full charge rate, which will indicate to the vehicle that this 'bulk power' is no longer needed. The alternator will then reduce the output provided, which results in a lower voltage output and a lower ability to harness power throughout the vehicle's system. This reduction in output from the vehicle means the vehicle is not working as hard and, as a result, will emit less pollution across the board. But this doesn't help those of us who want to charge secondary battery systems, as now we have a low-voltage output! This is where a DC to DC charger comes in.

The DC charger is designed to be installed in vehicles with low voltage outputs or variable (smart) alternators, as it will boost the low voltage output back to a higher output of approximately 14.4 Volts to your secondary battery. The DC charger is designed to be installed in between the vehicle starter battery and the secondary battery you are charging (whether the secondary battery is located in the rear of the vehicle, the caravan or even under the bonnet).

Choosing The Right DC to DC Battery Charger

DC chargers have become more common in today's market for the above reasons, and many brands are available for purchase, which can make things confusing to the average consumer looking to purchase one. So what do you need?

Consider this: the size of the DC charger will depend on what vehicle you're charging through (what size your alternator is) and the secondary battery bank you are charging.

If you are only charging one battery, say a 120 AH AGM, then a standard size 25 Amp DC charger is the perfect option. A 25 Amp DC charger will produce 25 Amps per EVERY HOUR you are driving. The DC charger needs a FULL 60 minutes of driving to deliver the nominated 25 Amps that the charger is rated to. This is the same when you choose a 40 Amp DC charger — you will need a full hour of drive time to produce the nominated 40 Amps from the DC charger and bring them back into your battery system. Once the vehicle has been switched off, then the DC charger is no longer operational.

Usually, a 25 Amp charger is standard for a secondary battery system of 1-2 batteries, around 120 AH each in size. When you increase your battery system from here, increasing the size of a DC charger to approximately 40 Amps is usually recommended. Consider this: if you had 3 x 120 AH batteries = 360 AH of total capacity, and you were only using a DC charger that was 25 Amps, then you would be looking at a charge time of approx 14.5 hours (360 / 25) if the batteries were completely discharged. If you instead opt for a 40 Amp DC charger, this charge time would be reduced to 9 hours (variables apply).

Home of 12 Volt recommends Projecta, Redarc, Victron and Powerhouse as good, reliable and cost-effective options for DC chargers. DC chargers will also 'isolate' the main battery from the secondary battery when the ignition is switched off. This isolation is designed to protect the starter battery and reserve it for the sole purpose of starting the vehicle.

Many DC chargers have a solar regulator connection offered as an additional component to the vehicle charge. The solar connection will act to regulate a 'non-regulated' solar panel to ensure it does not overcharge the battery it is connected to. Regulating a solar panel basically means that it will reduce the initial voltage produced by the panel (usually 17-24 volts) down to a voltage suitable to the battery (usually approx. 14.4 Volts).

Browse Our Range of DC to DC Chargers Today

Upgrade your off-road and camping setup with our robust and reliable DC to DC chargers. Designed for long-term use and built to perform, the chargers in our catalogue ensure your vehicle's batteries stay ready for adventure. Whether exploring remote destinations or powering essential gear, we provide customised solutions that fit your needs.

Browse our range of DC to DC chargers today and discover why many trust our products. We also offer a selection of 12-volt battery chargers and DC to DC chargers with solar input, giving you flexibility and control in any situation. If you have any questions about DC chargers, please contact our staff directly on 08 8391 3121 to discuss further.

FAQs

What is a 12-volt battery charger used for?

A 12 V - 12 V battery charger (or DC Battery Charger) is designed to charge and maintain 12V batteries commonly used in vehicles, caravans and camping setups. It can be used with various battery types, such as AGM, gel, lead-acid and lithium. It regulates the charging process to ensure optimal battery performance, extending the life of your battery and keeping it ready for use.

What types of batteries can be charged with a DC charger?

A DC to DC charger is compatible with a range of battery types, including AGM, gel, calcium and lithium. These chargers are designed to manage the specific charging needs of each battery type, optimising performance and longevity. Most models automatically detect the battery type and adjust the charging profile accordingly, ensuring a safe and efficient charge.

Do I need a DC to DC charger for solar?

Yes, and no. Many DC Chargers will act as a solar regulator, allowing you to connect an unregulated solar panel to charge your auxiliary battery. It regulates the energy from your solar panels, providing the correct charging current to your battery. This ensures your battery charges safely and efficiently, maximising the power you receive from the sun.

If you do not choose a DC Charger with a solar regulator, then you must ensure the solar panel is regulated either internally, or via the use of another solar charge controller. 

Do I need a DC to DC charger for a lithium battery?

Yes, lithium batteries require the use of a DC to DC charger to ensure adequate charging. Unlike AGM or lead-acid batteries, lithium batteries have different charging needs. A dedicated Lithium DC battery charger is ideal to regulate voltage and protect the battery from overcharging or damage, maximising its lifespan and performance.