How To Install a DC-DC Charger

Victron Energy 18A and 30A Orion-Tr DC-DC Charger


How to Install a DC-DC Charger

You’re on your way to that beautiful, secluded, off-grid spot you’ve been thinking about all day at work when you should’ve been compiling your monthly report. Furthermore, there won’t be a campsite for miles in any direction, so you’ll have the place yourself – sounds dreamy.

Unfortunately, it’s currently lashing with rain, and you’re concerned your solar panels won’t get enough juice into your leisure batteries to keep your phone topped up and your beers cold for your big weekend away. But, with a smirk, you remember the DC-DC charger you installed, which is topping up your batteries as you hit the open road and ensuring you won’t run out of power.

Want to get installed straight away? Jump to the step-by-step guide

If you have off-grid ambitions, DC-DC charging is a handy tool for van lifers. Rain or shine, off-grid or on-grid, all you have to do is drive your van (which you’re going to do anyway), and you can top up your leisure batteries, keeping the lights on and the beers cold for as long as you need.

This guide will look at installing a Victron Orion-Tr DC-DC charger, allowing you to make the most of your off-grid adventures. If you want to learn more about how to charge your leisure battery while driving – read our blog.

Build your own Electrical system

Everybody’s campervan conversion is different. There’s no reason your electrical system shouldn’t be too.

Use our campervan electrics system builder to create your own perfect system.

What Size DC-DC Charger Do I Need?

The 18A and 30A Victron Orion-Tr DC-DC chargers are an excellent addition to your van conversion. For instance, they’re both designed to charge a 12V/24V leisure battery array from a 12V/24V starter battery array. The main difference between them is the maximum current flow they will take from your starter battery (which is limited to 18A and 30A, funnily enough).

It’s worth noting that neither of these chargers will charge your leisure battery if your starter battery is not at a high enough voltage. So you will never accidentally drain your starter battery and need a jump-start from a friendly stranger! You may have heard the term smart alternator. If you are thinking, what is a smart alternator? – read our blog.

If you’re unsure which one is most suitable, why not try our handy off-grid calculator? This calculator is a nifty tool that calculates how long you’ll be able to stay off-grid based on how long you’ll spend driving and what other charging systems you want on your conversion.

If this is still a bit much, feel free to ring or email us; our friendly team is always delighted to help you achieve your dream van setup.

What Parts Do I Need to Install?

To install your DC-DC charger, you’ll need the following parts to hand:

  • A Victron Orion-Tr DC-DC charger
  • Single core red cable (wire size will be dependent on charger selection)
  • Single core black cable (wire size will be dependent on charger selection)
  • Unisolated lugs
  • Red and black heat shrink
  • 2 Midi fuses and fuse holders
Battery to battery parts (2)

It’s worth noting that if you’re using a combi fuse holder or Lynx Distributor, you won’t need a midi fuse holder. Instead, the fuse will be added directly to the combi fuse holder or Lynx Distributor.

If this looks like many parts and you’re unsure where to start, Vunked is on hand to help. You can even pick up everything you need for this system in one tidy package, taking the stress of ordering the correct size cables and lugs out of the equation. For instance, we currently stock Victron Orion-Tr 18A and 30A DC-DC chargers, as we believe these are the best on the market. 


Want all the parts required to install a Victron DC-DC charger. Have a look at our ready to build DC-DC packages below.

They come with all the parts required and an easy-to-use installation guide.

How to Install a DC-DC Charger

Van Battery Considerations

You’ll need to connect two cables to your van starter battery to install your DC-DC charger. However, the difficulty with this is that different models of vans will come with different ways to do this. Some will allow you to use the same lugs you use on your busbars, some will need bigger or smaller lugs, and others will look nothing like you’re expecting.

If you look at your van starter battery and don’t know where to start or can’t imagine how you could connect anything to it (which is how we felt during our first conversion), then don’t hesitate to give us a call or send us a photo of your battery.

Leisure Battery Location

In a nutshell, the wiring diagram below shows what you’ll be trying to achieve. Remember, any cables running from the DC-DC charger to your van’s starter battery will have to get there somehow.

This is a significant consideration if your electrical system will be at the back of the van since the starter battery is most likely at the front! Running cables through the walls, under the floor or above the ceiling are all excellent options. But make sure you decide before spending hours installing the floating roof you’ve always dreamed of.

DC-DC Installation

DC-DC Charger Installation Step-by-Step

So once you’ve got that figured out, follow the simple steps below to install your DC-DC charger:

  1. Connect the negative input from the battery charger to the negative battery terminal on your van’s starter battery.

  2. Connect the positive input from the battery charger to the positive battery terminal on your starter battery via the midi fuse. We recommend placing the midi fuse at the van starter battery – this way, if anything happens to the cable running through the floor/walls/ceiling, your starter battery is always protected.

  3. Connect the negative output from the battery charger to the negative busbar.

  4. Connect the positive output from the battery charger to the positive busbar via the midi fuse.
DC-DC Install close up

Hey, presto! Your DC-DC charger is installed. It’s not a complicated system to install once you’ve wrapped your head around what you need to do. The hardest part is choosing where your cables will lay and ensuring they’re long enough to be adequately terminated at the starter battery!

Having difficulty Installing a DC-DC Charger?

If you’re having difficulties with your installation and want expert support, don’t hesitate to get in touch. But, above all, If this has inspired you to press the button and install a DC-DC charger on your van, remember you can pick up the charger with all you need to install it, including the correct fuses and cable sizes, to make your installation a breeze.

Our 18A and 30A charging systems have everything you need. They come with free wiring diagrams, an easy-to-use installation guide and all the advice you can soak up.

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