How To Wire Up A Campervan With Solar Panels
Solar is the best way to power your van life adventures.
First of all, electricity is essential. Without it, we wouldn’t have lights, a fan, a fridge, device chargers or the ability to work remotely as digital nomads - basically any features that make your van a real home away from home. And solar panels allow you to explore and camp off-grid for as long as you want, absorbing the sun’s energy while you roam the roads.
But setting up your campervan’s electrical system is probably the most complex and daunting task that you’ll take on as a DIY builder.
As if getting to grips with this information wasn’t intimidating enough, working with wires is risky business and can bring serious consequences if certain steps are overlooked or completed incorrectly.
That’s why it’s so important to know exactly what you’re doing before you even begin to wire up your campervan’s solar system. If you brave it alone, always study your components’ manuals and consult with a licensed electrician before starting this stage of your van conversion.
Our advice is to hire a professional sparky to get the job done for you. While this will cost more than doing it yourself, you’ll enjoy peace of mind knowing that your van’s electrics are installed properly and safely. Not only will you stay out of harm’s way, you’ll also avoid expensive repairs in the future.
That said, every owner should understand the basics of their campervan’s electrical setup - just incase. To help you get started, we’ve put together a beginner’s guide to installing an electrical system in a campervan with solar power.
Safety Disclaimer: We are not electricians. Working with electricity is a safety hazard so you need to do your research, double (and triple) checking that the below information is correct and safe to apply to your build. Before you begin, always discuss your plans with a certified electrician, who must also assess and approve the finished work.
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Calculating Your Energy Needs
Before you can plan your electrical system, you’ll have to determine how much power it needs to provide. Essentially, you need to work out your demand before your design. Your very first step is to calculate how large your batteries need to be and how many solar panels will suffice.
What Size Battery Should You Use?
Begin by checking the amount of watts (W) each electrical appliance uses, and then multiplying this figure by the number of hours you expect to power it each day. This will give you the power consumption of each appliance, which is measured in watt-hours (Wh).
Watts x Hours = Wh
Once you’ve done this for every appliance, add up all of the Whs to get your van’s total power consumption. For the sake of this explanation, let’s say it’s 960Wh per day.
To determine your required battery capacity, which is measured in Amp-hours (Ah), divide your 960Wh of power consumption by the system’s voltage (12V).
Wh / 12V = Ah
With this formula, it might seem like you need a battery capacity of 80Ah.
In theory, yes. In practice, no.
To ensure that your battery doesn’t drain too much (below 50%), its capacity needs to be at least double the power consumption. Otherwise, you’ll damage your battery and reduce its lifespan. To be on the safe side, go for a 160Ah capacity or above. More is more.
How Many Solar Panels Do You Need?
Now work out how many solar panels you’ll have to mount to charge your batteries every day. Divide your 960Wh of power consumption by the standard hours of proper sunlight per day (about six) to see how many solar panels you need.
Wh / Hours of Sunshine = Solar Panel W
In an ideal world, that means you’d need 160W of solar energy each day.
In reality, the weather might be overcast, the area might have lots of shade or you might need to use more power than usual for whatever reason. It’s always best to round up your energy needs by roughly 20%. In this example, we’d recommend installing 200W of solar panels.
Another helpful approach is to use your battery capacity as a benchmark for calculating your solar panel’s wattage - you should have a minimum of 160W for 160Ah.
Choosing Your Electrical System Setup
To install a campervan solar system, you need several key components:
- Solar panels - absorb sunlight and convert its energy into electricity.
- Solar regulator - draws and controls the electrical current from your solar panels, optimising the rate at which your batteries charge. We recommend using an MPPT (rather than PWM) solar regulator, as it can produce around 15% more power.
- Deep cycle batteries - store this electricity so that you can use it for power.
- Inverter - converts your battery’s 12V direct current (DC) into 240V alternating current (AC), which can charge appliances with an ordinary plug.
- Battery monitor - displays handy information, such as your battery’s charge levels.
- Battery isolator - uses your van’s alternator to charge batteries as you drive.
- Wiring and fuses - safely connect all of the other components in your system.
We know - sounds like heaps! The good news is that you can find solar kits complete with all of the above components, bar the batteries and inverter. Each panel is usually 100W, and a single kit can provide up to four panels for your roof (but 400W is probably more than you’ll ever need on the road).
A solar setup can cost anywhere from $300-$2,500 and is 100% worth the investment. Not only is it super eco-friendly, all of your power needs will be covered without the need to depend on serviced campsites - provided you’re not running the AC or watching TV all day!
Of course, lots of us are converting our vans on a tight budget. If this is the case, you don’t have to buy a big, fancy solar system. Rather, start simple with a deep cycle battery, battery isolator, and inverter. This should do the job for basic power needs like charging your phone or laptop.
And you can always plug in more solar panels when you’re ready for an upgrade!
A Note On Batteries…
Let’s go back to basics for a moment. Of course, your van’s 12V electric system can run on a single 12V battery. However, some argue that it’s better to wire two 6V batteries in a series circuit to create a total of 12V. This setup may result in a deeper discharge time, or in other words, longer battery life.
Obviously, two batteries will take up more space than one so it’s up to you to decide whether the extended battery life is worth it!
Generators And Electric Hook Ups (Mains Power)
Solar power will meet the daily demands of most van lifers. However, if you need extra ways to charge up - particularly for power-hungry appliances like air conditioners, microwaves or TVs - then consider adding a 1000W generator or mains power connection to your system.
Be aware that generators are hefty. They cost a lot, take up heaps of space and produce a good bit of noise! So we don’t really recommend going down this route. However, if you decide to include a generator, consider attaching it to the back of your campervan with a hitch cargo carrier
Another option is to charge your batteries with mains power. Many camping grounds and holiday parks in Australia offer powered sites, where you can plug into an electric hook up - either install a power inlet in your van’s side or run a cable inside. To power appliances that draw lots of energy, make sure you have an inverter/charger
to load and convert your battery’s 12V DC to 240V AC output.
Learn how to include 240V hookup in your van’s electrical system here
Installing Your Electrical System
Unless you’re a sparky, there’s a high chance that you’ll make some mistakes. And as we’ve already stressed, errors can be extremely dangerous when you’re dealing with electricity. To minimise this likelihood, make sure to sketch your plans on paper until you know precisely which component goes where and why.
Creating a diagram will help you to visualise how your solar system will be laid out, what supplies you’ll need and how it all works. Once you’re confident in your design, run it by a certified electrician for advice and approval.
Choosing The Correct Wire Gauge
Finding the right size wire is really important to your electrical install. Wires which are too thin pose a serious safety risk, as your electrical current has to fit inside them. On the flip side, if your wires are too thick, they’ll be more difficult and time-consuming to work with.
The appropriate gauge depends on the maximum current that will run through your wire, as well as the length of your entire wiring system.
Your electrical appliances will display their maximum current under their technical specs. For DC appliances, this will be measured in Amps. For lighting, it is listed in watts. To calculate current from wattage, divide the watts by your system’s voltage (12V).
To determine the wire size for DC systems, measure the total distance that your positive and negative wiring will run and and then double it.
Once you have the above figures, use Blue Sea Systems’ awesome “Circuit Wizard” calculator
to determine the correct wire size for your van build.
Finding The Right Fuse Size
Available in many shapes and sizes, all fuses serve the same purpose: to protect your wiring. If your electrical current reaches a dangerous level, the fuse will blow intentionally to break the circuit and prevent major issues.
Here are some tips for fuse installation:
- Use fuses that are set to blow above your circuit load’s maximum current, but below your wire’s amperage rating.
- Install your fuse as near to the battery as you can. This minimises the length of wire that could carry a dangerous current.
- Fuse any circuit that will have a current running through it. A circuit is a complete electrical loop, from the positive (+) wiring to the component to the negative (-) wiring. You need to install a fuse on the active (+) wire.
Read the manuals for your battery, solar regulator and inverter to discover which fuse size to use in each circuit.
Crimping Your Wires
Remember to check that your connectors are suitable for your wires’ size. If you’re using wire that is thicker than 8AWG, we suggest buying it with pre-installed terminals or having the terminals installed at your retailer. Otherwise, you’ll have to buy a specially-designed crimper tool that applies enough pressure to connect bigger terminals.
Wiring Your Batteries, Solar Regulator And Inverter
Wire your batteries in parallel, first connecting the positive terminals together, and then the negative terminals together. Afterwards, mount your batteries to the floor of your chassis with self-tapping screws and shake-proof lock washers for a sturdy grounding.
Attach the solar regulator to your van’s interior wall with enough space for proper ventilation. Similarly, ground your inverter in a place with plenty of air flow, as it will generate lots of heat.
Then wire both your solar regulator and inverter directly to the battery, including an inline fuse for each.
Always connect wires to your batteries using opposite ends of the battery bank. That means connecting positive wires to the positive post of the first battery, and negative wires to the negative post of the last battery. This will charge and discharge your batteries at the same rate, which supports healthy functioning.
As you can see, this information is a very brief overview of the wiring process so please do not use it as your sole guide. Instead, check out these detailed guides to setting up your electrical system.
Mounting And Wiring Your Solar Panels
Many van lifers use 3M VHB tape to attach solar panels to their van, as this means they can avoid drilling holes in the roof. While this tape is super strong, others just don’t feel like it is enough, especially when they’re cruising down a motorway.
Thankfully, lots of solar power kits include self-tapping screws so that you can mount your panels to a sheet metal roof. Don’t stress if your van has a fibreglass roof - if this is the case, you can attach plywood strips on top, upon which you can then screw in your panels.
Once mounted, wire your solar panels in parallel. That way, it’s easy to add extra panels in the future. It also keeps each panel’s electrical current independent from the others. This means that if one panel is in the shade and its current drops, it won’t affect the other panels’ power output.
After you’ve joined all of the positive wires together and all of the negative wires together, feed them inside the van
to where your solar regulator is located. After your battery is wired up to the solar regulator
, connect your panels’ positive wiring to the positive solar terminal on your regulator. Do the same with your negative wiring.
Don’t forget to add an inline fuse between the panels and solar regulator. Additionally, never disconnect your battery if the solar panels and solar regulator are still hooked up. To avoid a blown fuse, always disconnect the panels first.
Wiring Your Lights and Vent Fan
To learn how to wire up your lights, visit our guide to lighting installation.
As you’ve (hopefully) already mounted your vent fan to the roof and fed its wires down into your van, all you have to do is join it all together! Use butt connectors to crimp extra wire onto your fan’s positive and negative wires. Then join the positive wire to your fuse box with a quick disconnect
, and the negative wire to your bus bar with a ring terminal.
Once you insert blade fuses into the fuse box, voila! Your lights and fan should be able to switch on. If they haven’t come to life yet, double check your solar regulator settings to make sure it’s not shutting off power to the load.
And there you have the basics of wiring up a campervan!
Again, we cannot stress how crucial it is to do your homework on electrical system installation - the above guide is only an introduction to some pretty complicated and dangerous work! If you’re doing it yourself, discuss your plans with an electrician and research, research, research before you begin. Once you’re finished, get the setup tested and certified by a trusted professional.
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