How To Install a DC-DC Charger in a Camper Van

Charging a camper van’s leisure batteries while driving is critical for those who require a reliable source of electricity during van life. This can be done by installing a DC-DC charger between your vehicle’s starting and leisure batteries. And the installation process is not as complicated as you might think.

Though we always recommend installing solar panels for your camper, it’s important to have a second method to charge your leisure batteries. And for many, installing a DC-DC charger is a popular choice.

This post will discuss what a DC-DC charger is and how to install one in a camper van. All the parts and components you need are included in this guide.

Let’s dive into it!

Victron | DC-DC Charger (30A)

Charge your leisure batteries quickly with Victron's 30A DC-DC charger (up to 360W). Works great for both lithium and AGM batteries. But the highlight is the charger's Bluetooth connectivity, which pairs with Victron's UX-friendly smartphone app.

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What Is a DC-DC Charger?

A DC-DC charger takes DC power from one battery and uses it to charge another battery. For camper vans and RVs, this device is mainly used to charge the leisure (house) batteries in the camper from the vehicle’s starting battery.

This charger is only activated when it senses that the engine is turned on. When the engine is off, the charger is also deactivated. This is to prevent the leisure battery from draining the starting battery. When the engine is on, there is no risk of draining the starter battery because the vehicle’s alternator ensures that the starter battery is continually being charged from the engine.

What Size DC-DC Charger Do You Need?

There are two specs to look at when determining which size DC-DC charger you need: DC voltage (V) rating and current (A) rating.

1. DC Voltage Rating

Before purchasing a DC-DC charger, you must know the following specs.

  1. Your starter battery voltage: In most cases, this battery will be rated for 12V.
  2. Your leisure battery voltage: A 12V leisure battery bank is most common, but some decide on a 24V system. (Read our 12V vs. 24V system post to learn more.)

Next, you must find a DC-DC charger that accepts your starter battery voltage and outputs the correct voltage to your leisure battery.

2. Current (Amps) Rating

A DC-DC charger’s current (amp) rating determines how fast the device will charge your leisure batteries. The greater the amp rating, the quicker the charger can charge the batteries, but the more expensive the device will typically be.

DC-DC chargers come in several different current ratings. The higher the amp-rating, the more power the charger can push to your leisure batteries to charge them. Below, we list three of the most common charger sizes.

Our Recommendation: If your daily energy usage is high (i.e., charging laptops, induction stove, heater), go with a charger that has a higher current (A) rating. But a smaller charger is sufficient if you only need to charge cell phones and power some LED lights.

Connect DC-DC Charger to Starter Battery

The first step to installing a DC-DC charger in a camper van is to connect the charger to the vehicle’s starting battery. Other than the charger, you will need the following products.

  • Red & Black 6 AWG Wire – These 6 AWG wires will safely handle the current when connected to the DC-DC charger.
  • 60A ANL Fuse – Protects the 6 AWG wire and downstream devices from over-current situations.
  • Copper Lugs (6 AWG & 3/8″) – Used to connect the 6 AWG wire to the 50A fuse and bus bars.

The above-recommended products are appropriately sized for both Victron’s 18A and 30A chargers.

Wiring diagram connecting the vehicle starter battery to the DC-DC charger
Wiring starter battery to DC-DC charger

Step-By-Step Instructions

  1. With 6AWG black wire, connect one end to the vehicle starter battery and the other to the negative input terminal.
  2. With 6AWG red wire, connect one end to the vehicle starter battery and the other to the 50A fuse.
  3. Connect the 60A fuse to the DC charger’s positive input terminal with 6AWG red wire.

Connect DC-DC Charger to Leisure Batteries

The second step is to connect the DC-DC charger to the leisure batteries. If you follow our electrical guide, you will know that we prefer to connect all our devices, including the DC-DC charger, to ‘bus bars’ instead of directly to the batteries. This helps to keep our camper’s electrical system clean and orderly.

If you haven’t already, you should pick up a pair of bus bars. They make the entire wiring process more manageable and cleaner. Instead of wiring every device (like inverters, solar charge controllers, and 12V panels) directly to the batteries, you connect them to the bus bars instead.

Bus Bars

Bus bars are power distribution centers that collect and distribute electricity to/from multiple sources. They simplify the wiring process and help keep electric wiring clean and orderly. Connects to batteries, solar charger, inverter, and DC-DC charger.

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The materials you need to complete this wiring section will be exactly the same as those in the previous step. So you can refer to the product table above to find the items,

Wiring the DC-DC charger to the leisure batteries
Wiring DC-DC charger to leisure batteries

Step-By-Step Instructions

  1. With 6AWG black wire, connect the charger’s negative output terminal to the bus bar.
  2. With 6AWG red wire, connect the charger’s positive output terminal to the 60A fuse.
  3. With 6AWG red wire, connect the 60A fuse to the bus bar.

Completed DC-DC Charger Installation Diagram

When completed, the result should look like the DC-DC installation diagram below.

DC-DC charger wiring diagram (final) connecting the vehicle starter battery to the leisure battery.
Complete DC-DC charger wiring diagram

Required Tools To Install a DC-DC Charger in a Camper Van

We recommend only three tools to help you install a DC-DC charger in your camper.

  • Wire Stripper – Cuts the 6 AWG wire to your desired length and strips away the protective jacket.
  • Hydraulic Lug Crimper – Crimps the copper lugs onto the 6 AWG wire. The hydraulic version is much better than the cheaper hammer crimper.
  • Heat Gun – Activates the heat shrink over the copper lugs and wire.

Why We Recommend Victron Orion DC-DC Chargers

Victron products have a reputation for being pricier than competitor products, but there’s a reason why they are the preferred brand among the camper van and RV communities. High-quality build, responsive customer service, and Bluetooth connectivity (to their Victron Connect app) make all Victron products an obvious choice.

With the Bluetooth-enabled Victron Orion DC-DC charger, you can easily connect to the device through Victron’s smartphone app. This makes monitoring your leisure battery charging easy. Additionally, through the Victron app, you can easily change any settings of the DC-DC charger to fit your battery’s charge profile needs better.

Below are the most popular Victron DC-DC chargers. (The first listed voltage corresponds to your starter battery, the second corresponds to your leisure battery)


We hope you found this DC-DC charger installation guide helpful. As we mentioned in the introduction, charging your leisure batteries while driving is a critical feature for all campers. This ensures you have a backup plan in case your solar panels can’t adequately charge your house batteries.

If you have any questions about wiring a DC-DC charger in your van conversion, please don’t hesitate to reach out through our contact form.

Happy building!

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