Can You Use a DCDC Converter to Charge Batteries? Converters vs Chargers

We're often asked: 

Can I use a DCDC converter instead of a DCDC charger to charge my auxiliary battery?

It’s a fair enough question - after all, DCDC converters are cheaper than DCDC chargers, and a cursory glance may suggest that they do the same thing. While it may be tempting to save some money, we’re here to share why we don’t recommend replacing a DCDC charger with a converter. 

In this blog, we’ll explain the differences between converters and chargers, and clear up the confusion around isolated and non-isolated models. 

Read more: DC-DC chargers

What is a DCDC converter?

A DCDC converter is designed to convert one DC voltage to another. For example, a 12V to 24V DCDC converter will take power from a 12V source and convert it to 24V. 

Example use case: You have a 12V battery system, but a device that requires 24V to run. A DCDC converter steps up the voltage, allowing you to power that appliance.

Converters are great at what they do - converting voltage - but that’s where their role ends. 

What is a DCDC charger?

A DCDC charger is specifically built to charge batteries. It takes power from your start battery (or another DC power source) and delivers it to your auxiliary battery, using a smart charging profile that protects and maintains battery health. 

Example use case: In a campervan setup, a DCDC charger draws power from the vehicle’s alternator/start battery and charges your house battery while you’re driving. 

DCDC chargers are designed to go through multiple charging stages (bulk, absorption, float, etc.) and can handle varying input voltages to deliver safe, regulated output - exactly what your batteries need to last longer and perform better. 

Read more: Calculating battery size for your caravan or 4WD

Why a converter isn't a substitute for a charger

A lot of people consider buying a DCDC converter instead of a charger to save money. But here’s the deal:

• Converters are not designed to charge batteries
• They send power at a fixed voltage but lack the intelligence to adjust charging profiles
• Batteries need precise voltage control and staged charging to remain healthy
• Over time, using a converter to charge a battery may reduce battery life and potentially cause damage

On the other hand, DCDC chargers are purpose-built to keep your batteries in top condition. Most modern models include Bluetooth connectivity and mobile apps, allowing you to monitor and adjust settings with ease. 

Bottom line: a DCDC charger is worth the investment when it comes to protecting your battery system. 

Read more: A guide on auxiliary batteries

Springers Solar DCDC charger setup

Isolated vs non-isolated: What's the difference?

Both DCDC converters and DCDC chargers come in isolated and non-isolated versions. Here’s a quick breakdown:

• Isolated models have four terminals: two positives and two negatives. The input and output sides are electrically separated. 
• Non-isolated models have a common ground, meaning they only need three terminals. 

Which one should you choose?

It mostly depends on your application:

• Isolated is ideal for boats or systems where you can’t use a chassis ground.
• Non-isolated is often fine in automotive setups where a common ground is used.

Performance-wise, they achieve the same result. Isolated setups may be slightly neater and offer more flexibility in grounding, while non-isolated options are often more cost-effective. 

So, can a DCDC converter replace a DCDC charger? We don’t recommend it. We recommend using components for their intended purpose. 

Use a converter for powering appliances that need a different voltage, and a DCDC charger for safely charging your auxiliary battery. Choose isolated or non-isolated based on your specific wiring needs.

Your batteries are a big investment - make sure you’re treating them right.

Read more: Why shunts and battery monitors are critical to your off-grid system

Springers Solar | Your Trusted 12V-48V Components & Accessories Supplier

We only stock the best brands in the extra-low voltage industry for the best prices - you can trust that when you buy gear from Springers, you are setting up your system to perform long-term. We don't waste our time or your time with low-quality products.

With an in-house team of 12V/24V/48V experts, we can offer advice and support as you set up your off-grid, off-road, or DIY battery system. We are Queensland-based and house our stock, so check out our online store here or visit us at Lawnton or Capalaba for in-store help.