Want to charge a laptop or blend a smoothie in your campervan? 😋 Well, you're going to need some plug sockets! To install plug sockets in a van conversion we need a 12v to 240v inverter. In this article we will learn all about campervan inverters, how to size them, the best brands, and how to install one. In our Roaming Home 2023 study we found that 60% of people installed an inverter in their van conversion. By the end, a large part of your van electrical system will be complete!
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 to this complete guide to campervan inverters!
Safety note: AC electricity is dangerous and can kill! If you are unsure about it, it is best left to a professional.
Note: Before we hop in, you might want to grab yourself a wiring diagram which you can get for free by signing up to The Van Conversion Newsletter
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Supplies List 🛒
What is a campervan inverter?
An inverter is a device that converts Direct Current (DC) electricity into Alternating Current (AC) electricity. In relation to a van conversion, it converts the 12V electricity from our leisure batteries into 110V (North America) or 240V (Europe).
Alternating current (AC) vs. Direct current (DC)
There are two kinds of electric current: direct current (DC) and alternating current (AC). Electrons move in one direction with direct current (batteries produce direct current). Whereas in alternating current, electrons flow in both directions.
Direct current flows in one direction: from the Positive (+) side of the battery, to the appliance, and back to the Negative (-) side of the battery. In a DC system, positive wire is typically coloured red, negative wire is typically coloured black. Car batteries are DC, typically 12V (12 Volt).
We can think of this movement of electricity like a river; it only flows in one direction.
Many van conversion electrical appliances will be 12V DC, such as the fan, heater, or lights.
With alternating current, the electrical force vibrates rather than flows. This is known as oscillation. In an AC system there is no positive or negative, current is instead transmitted through these vibrations. We can think of this like waves across an ocean: force moves, but the water does not.
AC electricity does not just flow in one direction, indeed it periodically reverses direction.
Mains electricity is AC, ie. the electricity you use in your house. In North America 110V is typically used for AC, whereas in Europe 230V is used.
An AC household appliance (eg. a kettle) will have 3 wires running to it: Live (brown), Neutral (blue), and Ground (green & yellow).
When converting a van, you may want plug sockets (so you can charge your laptop to watch netflix). These plug sockets are AC.
If you want to learn more about electricity as it relates to van conversions, you can read more here. The article covers volts, amps, watts, batteries, solar, AC, DC, and more.
An inverter may produce a square wave, sine wave, modified sine wave, pulsed sine wave, or near-sine pulse-width modulated wave.
Pure sine wave inverters give us much cleaner electricity as opposed to other types. In a pure sine wave inverter, the AC power produced closely matches the actual sine wave of AC voltage; it is smooth as opposed to stepped. This is especially important for very sensitive devices that we really don't want to break. Like our laptop. You should use a pure sine wave inverter as opposed to a cheaper stepped wave inverter.
One measure of the purity of a sine wave is Total Harmonic Distortion (THD). You should seek an inverter with less than 3% THD in the wave shape.
Surge vs. continuous rating
All inverters have a continuous rating and a surge rating. The surge rating is usually specified at so many watts for so many seconds. This means that the inverter will handle an overload of that many watts for a short period of time. A 1000W campervan inverter will typically have a surge rating of 2000W; a 2000W inverter will have a rating of 4000W.
High quality sine wave inverters are rated at 90-95% efficiency. Lower quality modified sine wave inverters are less efficient - 75-85%. Seek a pure sine wave inverter with over 90% efficiency.
Inverter efficiency also depends on load; with a high load the efficiency of an inverter can drop by over 5%. If you know you will be using high wattage appliances frequently, get a larger inverter to improve efficiency.
But do I actually need a campervan inverter?
An inverter is not an absolute necessity in a campervan. But it is rather nice to have! I use my inverter to power my fairy lights, run my coffee grinder, and use the blender.
There are some luxuries you can do without, but one thing many of us can’t live without is our laptop. Luckily, you can buy a simple step-up converter online to charge a laptop through a cigarette lighter socket. I have one - it’s excellent.
What size 12V to 240V inverter to use in your campervan
Sizing your inverter is very simple. You just need to figure out the total wattage you expect to use at any given time.
For instance, let’s say you will be charging a 90W laptop, while also using a 650W blender and a 170W electric blanket. This means your inverter must be able to handle 870W at a minimum. We will want to give ourselves a ~15% buffer on top of this, so we would go with a 1000W pure sine wave inverter at minimum (ideally larger for maximum efficiency).
In our 2023 study, we found that most people install a 2000W inverter.
Tips when using your campervan inverter
Make sure you turn off your inverter when you're not using it! Campervan inverters (especially cheap ones) passively suck energy from the batteries. Believe it or not, they can use up to 5A of power just being on.
Try to wire as many appliances as you can directly into your 12V DC system. When running appliances through a camper van inverter we can expect to lose 5-15% efficiency in the conversion of DC into AC. One easy place to save power is to charge our phones through USB cigarette lighter chargers, rather than through the plug sockets.
Best 12V to 240V inverter for campervans
The Budget Option
You can easily pick up a 12v to 240v inverter like this on amazon that will do the trick in a snap. These type of camper van inverters won't be as durable or efficient as their more expensive brethren, but they can good budget option! Make sure you get a pure sine wave inverter!
Top Pick: Renogy Pure sine wave inverter
Buying a pure sine wave inverter from a trusted brand like Renogy or Victron will be your best option long term. The product will last longer and is more energy efficient. Renogy make excellent inverters, and many van conversions are fitted with their 2000w pure sine wave inverter. It is a great choice.
I regret not buying this inverter the first time round as my cheaper campervan inverter brought me a lot of headache over the years.
If you are planning on also installing shore power in your van conversion (ie. charge your batteries by plugging into mains at a campsite), you should definitely check out an inverter / battery charger combo like this one. Yep... one device with double functionality. Save space and money!
Solar Inverter Charger
If you thought double functionality was nifty, how about triple functionality? The Renogy solar inverter charger combines:
80a Solar charge controller
3500w pure sine wave inverter
120a Battery charger
That’s monstrous… It also comes with mobile connectivity to monitor your devices/batteries. One thing to note is that this only works with 48V leisure batteries (which are pretty rare). In practice, this means that you will need to wire four 12V batteries in parallel (or two 24V). Certainly doable, but perhaps a bit of a mission. Still... I'm drooling over this device.
How to prevent ‘flickering’
Sometimes when the inverter draws a heavy load (eg. to power a space heater), other electrical appliances in the van may ‘flicker’ (eg. the lights). A large, high quality inverter will help solve this problem. If the problem persists, you might consider running the inverter directly from the leisure batteries, rather than from the shared bus bar. This adds a degree of separation from the 12V appliances.
How to install a pure sine wave inverter in your van conversion
Note: You can get a complete wiring diagram when you sign up to The Van Conversion Newsletter. The diagram shows you how to wire up your batteries, your campervan inverter, your solar, and everything else! I send out the wiring diagram straight away when you sign up.
Step #1: Choose a suitable location
Inverters tend to get quite hot when they are running - choose a cool, well ventilated location for installation.
Do not install the inverter in the same location as the battery bank. Though, to prevent excessive voltage drop, the inverter should be wired in close proximity to the batteries.
Step #2: Connect the inverter to the bus bars
The inverter has a positive and negative terminal on it. Wire the positive terminal to the positive bus bar and the negative terminal to the negative bus bar. I used 55 mm² cable for this, but you should do your own calculations for the wire size you need. The bus bars should already be connected to the leisure batteries.
Step #3: Fuse the inverter
On the positive wire, we will connect a 175A mega fuse (for a 1000W inverter) as close to the bus bar as possible; this protects the inverter (and wire) in case of a surge in electricity. Most 1000W pure sine wave inverters will allow for a surge/peak of 2000W for a short period of time. 2000W equates to 166A in a 12V system (2000W ÷ 12V = 166A). So our fuse should not blow at 166A, but instead be a little bigger, hence why we use a 175A fuse for a 1000W inverter. Ensure your cabling can also handle this amperage.
You can learn about fuse sizing here.
Step #4: Add a terminal switch
On the positive wire we also want to install a terminal switch. This is a big switch that allows us to easily turn off our inverter.
Campervan inverter wiring diagram
Step #5: Ground it
Check the manufacturer’s guidelines for more information on grounding your specific inverter. Some inverters need grounding, whilst others do not. If a consumer unit is required, its grounding will depend on the inverter. An RCD may or may not work depending on the model. You can learn all about ground for van conversions in this article.
Do I need an inverter consumer unit in my campervan?
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 GFCI, some don’t). Check the manufacturer’s instructions for specifics.
If the manufacturer recommends wiring up a consumer unit for your inverter, here is a diagram on how to do it!
How to wire up plug sockets in your van conversion
First, grab some three core cable and wire up a plug head! Here's what that looks like for a UK plug:
Remember, 3-core cable is insulated AC cable with live, neutral, and earth wires.
Pop the plug head into the front of your campervan inverter.
Run the 3-core cable from the inverter out to some double-pole (or unswitched) plug sockets. This is quite straightforward. Live to live (brown), neutral to neutral (blue), earth to earth (yellow/green). The installation for the plug socket is just like the plug socket we wired up for shore power.
If you want multiple outlets, you can wire up the sockets in a daisy chain fashion. This is known as a radial circuit.
You will likely be inserting the plug socket into a the plywood / tongue and groove wood in your van; you can use a jigsaw to easily cut out the shape of the plug socket and pop it into the cavity.
I hope you found this article on campervan inverters for campervans useful!
Don't forget to subscribe to The Van Conversion Newsletter for everything you need to get started with your own van conversion (I'll send you a free wiring diagram when you join).
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,