A van without an electrical system isn’t much to write home about… In fact, I think even calling it a campervan would be a stretch. Though a little daunting, installing your campervan electrical system is hands-down the funnest part of the build! In this guide, we will explore a campervan wiring diagram in depth.
I'm Shane, I've been teaching people to convert campervans for years; I'm the author of Roaming Home; The Comprehensive Guide for Converting Your Van Into a Campervan, writer of The Van Conversion Newsletter, instructor of The Van Conversion Course over at Udemy. And full-time vanlifer for 4 years!
So let's jump in and have a look at the campervan wiring diagram for your van conversion!
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Download the campervan wiring diagram
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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 the Campervan Electrics Explained article first.
Basic, intermediate, and advanced campervan electrical systems
In this guide, we will be walking through an advanced campervan wiring diagram in-depth. The electrical appliances in the advanced system can be a little pricey for some - so I have included a shopping list for a basic, intermediate, and advanced system below...
Basic electrical system
Intermediate electrical system
Advanced electrical system
How to get power/electricity into your van
There are three ways of getting power into your campervan:
Solar power harnesses the power of the sun through roof-mounted solar panels.
A split charger hooks up to the van's starter battery and allows you to charge your leisure batteries while you’re driving along.
Shore power allows you to hook up to mains at a campsite and charge up.
In the Roaming Home 2023 study individuals were asked which electrical system they were running in their van conversions. 84% of people are running a split charger (including B2B charger), 58% have shore power, and 78% have installed solar panels.
How is power/electricity stored in a campervan?
Electricity is stored in 12V leisure batteries in a campervan. There are many types of leisure batteries, the most popular being AGM and Lithium.
What do we use electricity for in a campervan electrical system?
Most van conversions have two electrical systems:
A 12V DC system
A 110V / 230V AC system
If you want plug sockets in your van (eg. to charge a laptop), you will need an AC system. An inverter is required for an AC system, it converts 12V to 110V / 230V.
Let’s step through the solar power portion of the advanced campervan wiring diagram.
In this campervan electrical system, we have four 18V monocrystalline solar panels wired in series, bringing the total voltage up to 72V. The total wattage is 400W.
The positive and negative wires run through a solar cable entry gland in the roof. 6 mm² wire is typically used for solar cables. I recommend Renogy's solar panel kits which come with everything you need out of the box.
Solar charge controller
The solar 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. Well worth it.
To protect our solar charge controller, we add a 40A DC double pole miniature circuit breaker (MCB) to the positive cable running to the charge controller. A breaker is like a fuse that can be reset once it is tripped.
We then run cable (typically 10 mm²) from the solar charge controller down to our positive and negative heavy duty bus bars (300A). 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.
On the way to the bus bar, we will add a 50A inline breaker (Bluesea or Bussmann) to the positive cable to protect the batteries and other appliances.
The last step of the solar system is running the busbars to our leisure batteries. We run a single positive and negative cable from each busbar to the leisure batteries. (typically 55 mm²) cable. Thought I encourage you to do your own wire sizing!
On the way to the batteries, we are going to install 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 terminal fuse 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.
In the Roaming Home 2023 study, we found that of those vans with either lithium or AGM (most popular lead acid) batteries, 46% are now using lithium batteries. Compared to even five years ago this is a huge jump. The benefits of lithium batteries are substantial, even if they do come with a higher upfront cost.
I recommend getting a single 200Ah lithium leisure battery - it is one of the better purchases you can make if you plan on using your van for years to come.
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.
A battery monitor with a physical display is very useful, even more useful is a bluetooth monitor like the Victron SmartShunt, which allows you to also monitor your batteries from your phone.
In the case of a Victron SmartShunt installation, install the shunt on the large negative cable running from your leisure battery to the negative bus bar. Then run a small positive cable directly from the positive terminal on your battery to the SmartShunt. Finally (optional), plug the battery monitor display into the shunt using the cable provided.
And that's the solar power system done! With this system done, you are ready for your first adventure. However, we're not finished yet! We're going to give this system some extra juice by installing both a split charger and shore power. So let's check out how those are installed...
Split charging is a pretty integral part of campervan electrics. Split charging connects your campervan starter battery to a leisure battery. This means that when you're driving along in your van, your leisure batteries are charged as well. There are two primary methods of split charging:
Voltage sensitive relay
B2B battery charger (smart charger)
In the Roaming Home 2023 study we found that 55% of van conversions are still using split chargers (SCR / VSR) rather than B2B chargers. Though there is no doubt that with the increasing popularity of lithium batteries, B2B chargers will soon take over. They are a far more efficient charger.
In the basic campervan wiring diagram we use a voltage sensitive relay (VSR). In the intermediate and advanced systems we use a DC-to-DC battery charger.
The DC-DC charger is installed on both a positive and negative cable running from the van's starter (crank) battery to the leisure batteries. On the cable we typically install a 100A fuse, followed by the charger, followed by another 100A fuse. We also need to install a D+ connection; this is a connection from the battery charger to the ignition of the vehicle. Further instruction on how to do this will be in the DC-DC charger's manual.
The next part of the campervan wiring diagram is shore power. Shore power allows us to 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 and use campsites a lot.
Safety note: AC electricity is dangerous and can kill! If you are unsure about it, it is best left to a professional. I recommend getting a professional to verify your system.
First we need to install a shore power inlet in the side of the van. This allows us to take AC 110V / 230V power into the van from the exterior. We should use 3-core cable (live, neutral, and ground), rather than just positive and negative 12V cabling.
We run 3-core cable from the shore power inlet to a double-poled consumer unit. A consumer unit is a distribution board that contains an RCD and several circuit-breakers.
From here, we run cable in two different directions;
1) From the consumer unit, we run 3-core cable directly to a plug socket (must be double pole or unswitched) - this allows us to power devices such as a laptop directly from mains when we are plugged in at a campsite.
2) From the consumer unit, we also run 3-core cable to an AC-to-DC battery charger, which in turn runs to our bus bars (and then on to our leisure batteries). The battery charger converts 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 inline breaker to the cable (10 mm²) between the battery charger and bus bars to give some added protection.
Below is a wiring diagram for the shore power consumer unit - please read this mains hook up guide for more information.
Campervan electrics: 12v DC appliances
Most of our campervan electrics are 12V; from the fan, fridge, and heater, to the water pump, lights and USB chargers.
The graphic below gives a breakdown of some of the most common electrical appliances, per the Roaming Home 2023 study. We did not include LED lighting in the study, as their installation is taken for granted.
To power these appliances we could run cable from the bus bars directly to the fuse box, however a better solution is to run cable from our solar charge controller instead. This allows us to power our 12V appliances directly from solar when the sun is out, rather than always running through our leisure batteries. It also gives us some extra monitoring capabilities for our 12V appliances.
Run cable (typically 10 mm²) from the solar charge controller to the fuse box. Then run cable for each appliance to the switchboard (typically 2.5 mm²). Finally run the same cable to each individual appliance. Please size your own wiring.
One of the most common appliances wel will wire up in a campervan are LED puck lights. You can learn all about LED campervan lighting in this guide. Here is a wiring diagram for how one might wire up LED puck lights...
To help you brainstorm some appliances for your van conversion, here is a list of 30 campervan accessories.
110/230v AC power
The next part of the wiring diagram is AC power. You may want plug sockets in your van - to charge anything from a laptop, to a nutribullet, to a dehumidifier. In order to facilitate this, you will need to install an inverter which converts 12V power from your batteries into 110V / 230V power for your AC devices! A 1000W or 2000W inverter will do the trick for most van conversions.
Safety note: AC electricity is dangerous and can kill! If you are unsure about it, it is best left to a professional.
To install an AC system, run some thick cable (35 mm²) from your positive and negative bus bars to the inverter. Then wire up a plug head with some 3-core cable and plug it into your inverter. Run the cable from the plug head to some double-poled plug sockets in the van.
Note: You may require a consumer unit, installed between the inverter and sockets. The addition of a consumer unit here is dependent on which inverter you have (some inverters have GFDI, some don’t). Check the manufacturer’s instructions for specifics.
It's important that we size our inverter correctly. If you're using something like an electric kettle or blow heater that takes a lot of wattage, you need to ensure your inverter is big enough to handle it.
In our 2023 study, we found that most people install a 2000W inverter. Renogy's 2000W pure sine wave inverter is a popular choice.
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, the ground is the chassis of the van. You can use an existing ground point or install a new point in the chassis. You can then wire anything that needs grounding to that bolt. Run all grounds to the same ground point. Keep AC and DC ground separate.
Here is what you must ground in a campervan:
Starter battery (should be grounded already)
Negative bus bar - this grounds your leisure battery and the other components in the electrical system
Shore power (EHU) consumer unit
Here is what you might need to ground (consult the manufacturer’s guidelines):
Inverter & inverter consumer unit
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 campervan wiring diagram by joining the newsletter here - I'll send it out right away 📪
If you're looking for some guidance with your van conversion, you might be interested in Roaming Home; The Comprehensive Guide for Converting Your Van Into a Campervan. In the 380-page book (or ebook), you'll learn directly from me how to convert a van into your dream home - no prior experience needed!
Until next time,