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Campervan Wiring Diagram Walkthrough (Free Download)

Updated: Oct 19

A campervan without an electrical system is... well, just a van. Installing campervan electrics is hands-down the funnest part of the build, though it can be a little daunting! In this article, we are going to explore a campervan wiring diagram in-depth. I will also supply you with a download of the campervan wiring diagram. By the end you will have a thorough understanding and overview of the campervan electrical system and be ready for your own electrical installation! I'm Shane, I've been teaching people to convert campervans for many years, I'm the author of The Van Conversion Newsletter, the van conversion instructor at Udemy, and the proud owner of a beautiful self-build campervan called Beans. So let's jump in and have a look at the campervan wiring diagram for your van conversion!


The best van conversion electrical system

Note: Items linked in this guide are paid affiliate links. By using these links, you are helping me to continue writing free educational van conversion content!

You can find the full list of van conversion supplies here.


Index

 
 

First, download the high quality version of the campervan wiring diagram

Get the high quality (4k) version of The Van Conversion wiring diagram (complete overview with wire sizes, fuse sizes, appliances, etc.) by signing up to The Van Conversion Newsletter. I'll send you the campervan wiring diagram as soon as you join! Plus, every now and then I send out juicy van-related content; build guides, resources, videos, inspiration, and discounts.

Van conversion electrical diagram

Note: Before we dive into the campervan electrics, If you want a refresher on your knowledge (including amps, volts, watts, fuse and wire sizing, AC vs. DC, solar and battery sizing), you might want to check out this article first.


Let's first explore three key sections of the campervan wiring diagram at a high level:

  1. How to get power/electricity into your van?

  2. How is power/electricity stored in a campervan?

  3. What do we use electricity for in a campervan?

After we explore those three questions, we will move into more detail on specifics.

Your van will look like this 👇👇 in no time!

Cosy van electrics
My cosy van 'Beans' 🥰

How to get power/electricity into your van

There are three ways of getting power into your campervan, you can see those three methods on the left side of the diagram above. Those methods are:

  1. Solar power

  2. The alternator (Split charging)

  3. Shore power

Solar power requires having solar panels attached to your roof - either flexible or solid. A split charge relay hooks up to the van's battery and means that when you're driving along in your van, it charges your leisure batteries as well. Finally, we have shore power which means if we are at a campsite, we can hook in to the mains and charge up.


I personally have 4 X 100w solar panels on the roof, a split charger, and shore power.


How is power/electricity stored in a campervan?

Electricity is stored in 12v batteries in a campervan. Specifically, we call these batteries leisure batteries. There are many types of leisure batteries, the most popular being AGM, lead acid, and Lithium.


I have 2 X 135aH AGM leisure batteries, wired in parallel. Having used them for the past three years, I now recommend getting Lithium batteries for reasons discussed here.

Van conversion leisure batteries in parallel

What do we use electricity for in a campervan?

In a van conversion, electricity is used for many, many things! Most campervans will have two systems:

  1. A 12v DC system

  2. A 110/230v AC system

Most appliances will run off the 12v system - directly from the leisure batteries (including a fan, fridge, lights, heater, etc.)

Van conversion 12v appliances

However, you will also want plug sockets in your van, so you can do things like charge a laptop. In order to have this facility, you need to install an inverter which converts the power of the 12v batteries up to 110/230v. You can learn all about inverters in this guide.

Van conversion inverter 230v AC sockets

Solar power

Okay, now let's dive into the campervan wiring diagram in more detail. Let's start by running through the solar power system in depth! If you want a mega-deep dive into solar panels, read this guide.


Solar panels

In this campervan electrical system, we have four 18v solar panels wired in series, bringing the total voltage up to 72v. I used 4X monocrystalline solar panels.

Van conversion monocrystalline solar panels series

The positive and negative 10AWG wire runs through the cable entry which we installed in the roof of the van. Here is the guide on how to install the solar cable entry gland in the roof of your van.


Solar charge controller

The cable runs to our solar charge controller - a device which keeps the battery from overcharging by regulating the voltage and current coming from the solar panel to the battery. There are two types of solar charge controllers: MPPTs and PWMs. MPPTs are a little more expensive (marginally), but accelerate solar charging of the battery up to 30% per day. I have an Epever 40a MPPT Solar charge controller. You can also plug an MT50 remote display into your solar charge controller for extra solar and battery monitoring. I would highly recommend this - I have found it to be a very useful device. Renogy's solar charge controllers are also excellent.


To protect our solar charge controller, we add a 40a breaker to the positive cable running to the charge controller. A breaker is like a fuse that can be reset once it is tripped. You can learn about fuses and breakers in this guide.

Van conversion MPPT solar charge controller

Bus bars

We then run cable (I used 8AWG) from the solar charge controller down to our positive and negative bus bars. The bus bars are a way of centralising all the positive and negative wires in our system so that we can easily route onwards to the leisure batteries through one single cable (for both positive and negative). They keep our cabling neat and tidy. An alternative to using bus bars would be to route all positive and negative cable in the system directly to the leisure batteries - but can be sloppy. I used two 300a bus bars in my campervan electrical system.


On the way to the bus bar, we will pop a 50a breaker on the positive cable to protect the batteries and other appliances.

Van conversion bus bars

Leisure batteries

The last step of the solar system is running the busbars to our batteries. We run a single positive and negative cable from each busbar to the leisure batteries. I used 0AWG cable for this (Very beefy 🐮). Learn all about leisure batteries here.


On the way to the batteries, we are going to chuck an isolator switch on the positive line (a giant switch that will cut-off all campervan electrics if switched). We will also add a 250a fuse (or similar) onto the cable as a last ditch effort to protect the batteries in case of electrical overload.


Some people will opt for a single leisure battery, while others will opt for multiple batteries, thus increasing storage capacity. If you are using multiple batteries, make sure you wire them in parallel to keep the voltage at 12v; if you wire in series the voltage increases as a factor of the number of batteries attached. I used two 130aH leisure batteries.

Van conversion leisure batteries and battery monitor

Battery Monitor:

You can optionally also add a battery monitor to your campervan electrical system. A battery monitor gives insights into the health and usage of your leisure batteries.


To install a battery monitor, install a shunt on the negative cable running from your negative bus bar to the leisure battery. Then run some smaller cable from the shunt to the battery monitor. Finally run a cable (I used 14AWG) from the positive bus bar to the battery monitor in order to power it.


To be honest, if I were doing the campervan electrics again I would not install a battery monitor. I have found the MT50 monitor for the solar charge controller to be far more useful (and easier to install), with just as much information. You could also use Renogy's bluetooth mobile monitor

van conversion battery monitor

And that's the solar power system done! With this system done, you are ready for your first adventure. However, we're not done yet! We're going to give this system some extra juice by installing both a split charge relay and shore power. So let's check out how those are installed...


Split charging

This is a pretty integral part of campervan electrics. Split charging connects your campervan's starter battery to it's leisure batteries. This means that when you're driving along in your van, your leisure batteries are charged as well. You can learn all about split charging in this guide. There are two primary options for split charging:

  1. Voltage sensitive relay

  2. DC to DC battery charger

Van conversion split charge relay

We run a positive cable from the van battery to our positive bus bar (which in turn runs to our leisure battery as we saw before). On the cable we install a 100a fuse (to protect the split charge relay) followed by the split charger, followed by another 100a fuse.


Shore power

The next part of the campervan wiring diagram is shore power. Shore power allows us top hook up to mains and charge up (eg. at a campsite). I have found shore power essential to my van travels as I travel a lot in winter.

Van conversion shore power victron consumer unit

First we install a mains shore power inlet in the side of the van (read the guide on how to do that here). This allows us to take AC 110/230v power into the van from the exterior. As a result, we will be using 3-core cable (live, neutral, and ground), rather than just positive and negative 12v cabling. It is recommended to use stranded wire rather than solid wire in van conversions due to the shaking of the vehicle, though this is getting nitty-gritty.


We run 3-core cable from the shore power inlet to an RCD consumer unit (garage unit). A consumer unit is a distribution board; an apparatus that contains a switch (RCD) and two circuit-breakers.


From here, we run cable in two different directions:


a) From the consumer unit, we run 3-core cable directly to a plug socket - this allows us to power devices (eg. laptop) directly off mains when we are plugged in at a campsite.


b) From the consumer unit, we also run 3-core cable to a battery charger, which in turn runs to our bus bars (and then on to our leisure batteries). The battery charger converts 110/230v AC power into 12v DC power so that we can charge our batteries. It also monitors and regulates the inflow of electricity to ensure a safe system. We add a 40a breaker to the cable between the battery charger and bus bars (I used 8AWG) to give some added protection.


12v DC appliances

Most appliances in our van are 12v; from the fan, fridge, and heater, to the water pump, lights and USB charger. Thus, 12v DC appliances are included in the campervan wiring diagram!


Each appliance is fused appropriately from a 12v fuse box. The appliances also run through a switchboard so that we can easily switch an appliance on and off. You can learn all about fuses in this guide. You can learn about wiring a switchboard here.

van conversion 12v appliances fuse box and switchboard

To get power to these appliances we could run cable from the bus bar to the fuse box, however an even better solution is to run cable from our solar charge controller instead. I love this solution because the MPPT gives us a bunch of monitoring capabilities for our 12v appliances.


So, run cable (I used 8AWG) from the solar charge controller to the fuse box. Then run cable for each appliance to the switchboard (I used 14AWG). Finally run the same cable to each individual appliance.


A close up look at the Epever 40a MPPT

The Epever MPPT has three separate ports:

  1. (Left) Input power from solar panels

  2. (Center) Output power to leisure batteries (after solar charge controller converts solar electricity to clean 12v, it is routed to the leisure batteries)

  3. (Right): Run cable out to our 12v appliances. This is optional as I mentioned above, but I would highly recommend it :)

Epever 40a MPPT solar charge controller explanation

110/230v AC power

The next part of the campervan wiring diagram is AC power. You will very likely want plug sockets in your van - to charge anything from a laptop to a nutribullet. In order to facilitate this, you will need to install an inverter which converts 12v power from your batteries into 110/230v power for your AC devices! I used a 1000W inverter.

110/230v AC power for van conversions inverter

The inverter installation is actually a very simple part of the campervan electrical system. Run some thick cable (I used 2AWG) from your positive and negative bus bars to the inverter. Then wire up a plug head with some 3-core cable, plug it into your inverter and then run the cable out to some electrical plug sockets in the van.



How to wire a UK plug head
How to wire a UK plug head

Note: It's important that we size our inverter correctly. If you're using something like an electric kettle that takes a lot of wattage, you need to ensure your inverter is big enough to handle it.


Learn all about Inverters for van conversions here.


How to ground van conversion electrics

Grounding your electrical system is an essential safety feature that protects your system from damage or even fire. In a campervan, ground is the chassis of the van. You can simply drill a bolt (ensure it is raw, untreated, and unpainted) into the chassis, and then wire any appliance that needs grounding to that bolt.


There is some controversy in the van conversion community about what actually needs to be grounded.


Here are the four things you should ground in your van conversion (always better safe than sorry):

  • Solar charge controller

  • Split charge relay

  • Leisure batteries (Absolute necessity!)

  • Inverter

Learn all about ground for van conversions here.


Conclusion

There we go! Take a deep breath 🫁 You made it through the whole campervan electrical system!! My advice is to go through the campervan wiring diagram several times to wrap your head around it fully. It's not hard once you understand it, I promise. As I mentioned at the start, you can get a free 4k version of The Van Conversion wiring diagram by joining the newsletter here - I'll send it out right away 📪


I mentioned a lot of electrical supplies throughout this article - you can check out the complete list of supplies I used for the electrical system in my van conversion here.


Finally, if you have any questions at all, please post them in the comment section and I will be sure to get an answer to you! Let me know in the comments which campervan electrical system you went for!


I truly hope you found this guide to van conversion electrics useful! You are well on your way to a beautiful self-build campervan! If you're converting a van but unsure of how to do it, you could also check out the Van Conversion Course on Udemy. In the course, you'll learn directly from me how to convert a van into your dream home - no prior experience needed!


Until next time,

Shane ✌️