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DC-DC Chargers and why we need them

Are you wanting to know more about DC-DC battery chargers and how they can enhance your campervan’s functionality? Let’s dive in.

Maintaining a reliable electricity supply in your van is essential, particularly for extended journeys. It ensures your van stays illuminated, energizes your electrical outlets, and powers vital appliances like your refrigerator, heating system, and water pumps.

There are a few methods to recharge your campervan batteries, including:

• Alternator (DC-DC)

• Solar, and

• Shore Power (Plugging it in); this method necessitates an inverter/charger.


One component that raises a lot of questions is the DC-DC battery charger. What is a DC-DC battery charger and why do you need it?

In this guide, we’ll discuss: • The definition, function, and significance of a DC-DC battery charger. • A brief comparison of the DC-DC battery charger with other alternatives.


Let’s get started!

What is a DC-DC Battery Charger? Simply put, your vehicle’s alternator produces electricity and charges the vehicle battery while you’re on the move. In a campervan, you use this same alternator to charge your house batteries. These batteries power the internal components of your campervan, like lights, and are typically Lithium or AGM batteries.

By default from the factory, your alternator is set up to know when your vehicle battery is charged and how much power the alternator needs to put out. It’s not designed to know about the campervan conversion you have going on in the back.

That’s where the DC-DC Battery Charger comes in.

Why do You Need a DC-DC Charger?

To understand why a DC to DC chargers are required, it is best to understand a little about the differences between lead acid batteries and lithium batteries.

Lead acid based batteries exhibit higher internal resistance to charging, which in turn reduces the demand from the alternator. Conversely, lithium batteries have very low internal resistance. As a result, when a lithium battery is connected to an alternator, it demands maximum output. While your alternator may handle this while the engine is running at high speed and adequately cooled, the same load can damage the alternator when it is idling due to insufficient air flow, leading to an increase in temperature and potential burnout of the windings.

In short, the DC-DC Battery Charger is the brain that acts as a gateway that provides the correct voltage for charging the Lithium battery and acts as a current limiter.

Alternator -> DC-DC Battery Charger -> House Battery

How Does a DC-DC Battery Charger Work?

The DC-DC battery charger uses your van’s alternator (an electrical generator) to convert the available power. It then converts that power to a higher voltage for your secondary battery (i.e. your house battery).

Here’s how the DC-DC charger uses a 3-step process to charge your battery optimally.

  1. Bulk: In this step, the DC-DC battery charger converts the current from the alternator and fills in the secondary battery almost to the maximum.
  2. Absorption: Here, the power levels off and stabilizes so the battery doesn’t ‘overcharge’.
  3. Float: This occurs when the battery is fully charged with its optimal capacity reached.

Understanding the Advantages of a DC-DC Charger

Let’s delve into several advantages you’ll experience when utilizing a DC-DC charger.

Navigating Smart Alternator Challenges

Present-day vans typically have smart alternators that are created to lessen power output. Due to their load limitations, these alternators can’t charge a secondary battery. However, a DC-DC converter eliminates this hurdle by separating the primary battery from the alternator.

Enhancing Main Battery Charge

Installing a DC-DC battery charger has another perk – maximizing the primary battery’s charge. This charger can transform voltage from as low as 9 volts to as high as 13.5 volts, enabling quick and effective charging of the main battery.

Functionality Without Solar Power

If you often travel in regions with limited sunlight, a DC-DC charger can be a significant advantage. These chargers can charge an auxiliary battery, enabling you to power your devices without relying on solar power or other backup energy sources.

Compatibility with Various Battery Types

One of the most notable advantages of a DC-DC battery charger is its ability to adapt to different battery types. This feature can save you the time and expense of purchasing a new charger whenever you replace your battery. Moreover, a DC-DC charger can tailor the power based on the battery’s intended use, reducing battery damage from overcharging.

Can I Use a DC-DC Charger with Lithium Batteries?

Yes, you can definitely use a DC-DC charger with lithium batteries as it can optimize your battery life. A DC-DC charger can also extend your lithium battery life.

Here’s a summary of its functions

  • A DC-DC charger provides the correct voltage to the lithium battery, ensuring the charging voltage is not exceeded.
  • A DC-DC charger effectively controls the power demand from a lithium battery, ensuring it doesn’t overheat the alternator when charging.
  • Lithium batteries have a unique restart process and specific battery chemistry, complicating their charging through alternative methods, like an alternator.


At SOK Battery we recommend Victron DC-DC Chargers

Victron DC-DC chargers such as the Orion-Tr Smart isolated/non-isolated are one of the most popular brands in the market right now with the following features:

  • Works well with both 12-volt and 24-Volt systems and lithium and lead-acid batteries.
  • Includes Bluetooth so you can control the power settings from the comfort of your cellphone via an application.
  • It is durable and can adapt to high temperatures.
  • Includes a switchable remote loop to enable and disable the DC-DC charger remotely






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