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How To Install A DC-DC Charger In A Camper Van

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Charging a camper van’s leisure batteries while driving is a critical ability 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 battery and your leisure batteries. And the installation process is not as difficult 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.

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

Let’s dive into it!

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 most 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.

Victron Orion DC DC Charger (30A)
Victron Orion DC DC Charger (30A)

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 will need to 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 need to find a DC-DC charger that accepts your starter battery voltage and outputs the correct voltage to your leisure battery.

  • 12V starter battery and 12V leisure battery? Get a 12V/12V charger
  • 12V starter battery and 24V leisure battery? Get a 12V/24V charger
  • 24V starter battery and 12V leisure battery? Get a 24V/12V charger
  • 24V start battery and 24V leisure battery? Get a 24V/24V charger

2. Current (A) Rating

The current (amp) rating of a DC-DC charger determines how fast the device will charge your leisure batteries. The greater the amp rating, the faster the charger, but also the more expensive the device will typically be.

DC-DC chargers come in lots of different current ratings. For example:

*All links above go to Amazon.com

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 if you only need to charge cell phones and power some LED lights, a smaller charger is sufficient. We use the Victron 18A charger, but would upgrade to the 30A charger if we could do it again. Doing so would make our electric system more resilient during the winter season and consecutive cloudy days.

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: (All links lead to Amazon)

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

Part 1 of our DC-DC charger wiring diagram showing the 12V DC charger being connected to the camper van starting battery.

Step-By-Step Instructions

  1. With 6AWG black wire, connect one end to the vehicle starter battery and the other end to the negative input terminal.
  2. With 6AWG red wire, connect one end to the vehicle starter battery and the other end to the 50A fuse.
  3. Connect the 50A fuse to 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 to ‘bus bars’ instead. This helps to keep our camper electrical system clean and orderly.

Other than the charger, you will need the following parts and components (all Amazon links):

Just as in the previous step, all recommended products are sized for Victron’s 18A & 30A chargers.

Part 2 of our DC-DC charger diagram showing a 12V DC charger being connected to the bus bars of a camper van.

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 50A fuse.
  3. With 6AWG red wire, connect the 50A fuse to the bus bar.

Completed DC-DC Charger Installation Diagram

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

DC-DC charger wiring diagram for camper vans.

Required Tools To Install A DC-DC Charger In A Camper Van

There are only three tools we recommend to help you install a DC-DC charger in your camper. (Links to Amazon product pages)

  1. Wire Stripper – This tool strips the protective jacket and exposes the copper wires.
  2. Hydraulic Crimper – This crimping tool makes it super easy to crimp thick copper lugs onto your wire ends. Don’t be cheap and get this hammer lug, like we did. It makes inconsistent and weak crimps. This hydraulic crimper will also be useful for other parts of your electrical system build.
  3. Heat Gun – Activates the heat shrink material that covers the copper lugs and wires. All our recommended copper lugs come with heat shrink.

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), makes 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 better fit your battery’s charge profile needs.

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)

DC-DC Charger

Buy Wire

12V/12V - 18A

12V/12V - 30A

12V/24V - 10A

12V/24V 15A

Conclusion

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

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

Happy building!

Thank You For Reading!

We’re Yuko and Eric! We both grew up in Asia ( Japan & Hong Kong ), we left our jobs and homes in 2018 and started traveling full time from Canada to Argentina in our self-converted camper van since end of May 2019. “Asobo” means “Let’s play” in Japanese. We named our site “Asobolife” because the life is always uncertain and we live only once so it’s important to always keep positive, playful mind and enjoy the moment you are in the present. We also want to use this website to share our road trip and van building experiences to inspire our readers. We hope you enjoy!

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