How To Build A Campervan Electrical System [DIY Guide]
last updated: Apr 7, 2022
A campervan electrical system is one of the most fundamental and important parts of any campervan conversion.
Having an electrical system can be what takes your campervan setup from car camping, to truly experiencing vanlife.
After all, the campervan battery setup is what provides you with lights, hot running water, charges your devices, and stores your food. Without it, your van won’t have those creature comforts.
While the campervan electrical system is one of the most important parts of a van conversion, it can also be the most daunting.
We know that not everyone setting out to convert their own campervan has in-depth knowledge of how an electrical system works- and most have no knowledge at all!
That’s why in this article, we break down all the working parts of a campervan electrical system in a simple, easy-to-digest way.
From what the pieces are, what they do, and even how to install them.
And, we’ve even included three different examples of campervan electrical systems with a full-cost breakdown so you can pick and choose the perfect electrical setup for your dream campervan.
Starting off with..
Part 1: How the Electrical System Works
A van life electrical system consists primarily of three parts: The battery (or power source), the charging source, and the loads.
The battery holds the power in your campervan, and also runs your van’s power load. Then, the battery is recharged by your charging source.
The power source, also known as your power storage, is the battery of the campervan.
Because most campervans run on 12V systems, most campervan batteries are 12V DC.
The three most common types of campervan batteries are:
AGM stands for absorbent glass mat. It is a sealed battery, and doesn’t need to be refilled like a flooded battery.
AGM batteries can be stored any way in a campervan, and charge much quicker than Gel Batteries.
The biggest drawbacks of AGM batteries are that they can only be safely discharged to 50%, and they are quite heavy.
Gel batteries are filled with a gel made from silica and the gel operates as an electrolyte.
Gel batteries are slightly larger than AGM batteries, but their biggest pluses are that they have a longer lifespan, and function better in extreme temperatures than AGM batteries.
A Lithium battery can be discharged at a lower rate than both Gel and AGM batteries. They can safely be discharged to 20%.
They also charge much faster than AGM and Gel batteries, and are only a fraction of the size.
Due to their efficiency and longevity, Lithium batteries are by far the superior option of the three. However, they are also the most costly!
Your campervan’s battery will provide all of the electricity in your van. Items like your lights, your phone chargers, fridge, and more- these will all be powered by your battery!
The more items you need to power in your campervan (also known as your power loads), the more power you will need to be able to store in your van.
This may even mean having multiple batteries in your campervan. After all, the more power you can store in your van, means having more power to your electrics, which means more time off-grid!
The Charging Source
While your battery is the source of power in your van electrical system, usage of the battery will slowly deplete it, and the power will need to be restored.
There are three primary ways to recharge your battery in a campervan: Shore power, solar power, and an alternator.
Shore power consists of pulling power from an outlet to recharge your campervan’s battery. However, campervan batteries run on 12V DC, and most houses and everyday appliances run on 120V AV.
Due to this difference, in order to charge your campervan battery from an outlet source at a house or RV park, you will need a DC to AV convertor.
Solar power is one of the best ways you can charge your campervan’s battery! It’s cost-effective, energy efficient, and in sunny locations, the supply of power is essentially infinite.
To charge your campervan’s battery using solar power, you will have to install solar panels onto the roof of your campervan.
The solar panels will harness the sun’s energy, and your charge controller will turn it into a voltage that charges your campervan’s leisure battery.
Check out our campervan solar system guide for a deep dive on van solar power!
When the engine of a vehicle starts, the alternator begins to spin, which then charges the vehicle’s battery and provides power to the entire vehicle.
Every vehicle has an alternator, and that alternator can be used to charge not just your car’s primary battery (the one that powers the ignition/ headlights/ cab lights), but also your campervan’s leisure battery for your electrical system!
An alternator is a great supplemental power source to solar panels, and is particularly useful in the winter, or on cloudy days in general!
The Power Load
The campervan power load is everything that is running off of your campervan electrical system.
This can consequently be broken down into two categories: 12V DC and 120V AV loads.
Because campervan batteries are 12V DC, electronics that also run on 12V DC are going to be way more efficient, because no power voltage conversion will be necessary to run those electronics.
Some common items in your campervan that run on 12V DC might include: LED lights, a 12V refrigerator, a composting toilet, 12V power sockets, and heaters.
In a house, the power source is 120V AC rather than 12V DC. This means that any household items you would plug into a typical house outlet, are also going to run on 120V AV, including items like blenders, microwaves, and coffee makers.
To run 120V electronics off of a 12V battery, you will need an inverter to convert your power from 12V to 120V.
Because 120AV electronics require an inverter, you will actually lose power while converting DC to AV.
This means that unless you’re plugged into shore power, using AV electronics is way less efficient than DC. To have the most efficient campervan electrical system possible, it’s a good idea to try to stick to power loads that run on DC!
Part 2: Campervan Electrical System Important Considerations
How much power do you need?
Now that you understand roughly how a camper electrical system works, the next important step in installing your campervan’s electrical system is to figure out exactly how much power you need in your campervan.
A good way to do this is to consider all of the items in your campervan you may want to power. Common campervan electronics include:
- Water pump
Those are some of the most common campervan electronics. However, every vanlifer has different needs, and there might be some different power loads that you’ll have in your van.
That’s totally okay, the following equation can be applied to any different load.
The equation to calculate how much power you need
After listing out all of your campervan’s electronics, you plug them into this equation:
Daily Power Usage (Ah) = Amps (A) x Time (H)
Amps are the amount of electricity that the electronics you use need to run. You can find this number for each of your electronics via a quick internet search, or in their user manuals.
When you multiply that by the amount of time (measured in hours) you run those loads(electronics), you will arrive at your daily power usage.
- Your Maxxair Fan draws 3 Amps.
- Your Maxxair Fan runs 3 hours a day.
- Plug it into the equation:
Daily Power Usage (Ah) = 3A x 3h
- Your Daily Power usage for your Maxxair Fan will be 9AH
To calculate your total daily usage, simply use this formula for all of your campervan’s loads, and you’ll arrive at your total daily power usage!
What size battery bank should you opt for?
Once you’ve calculated your total daily power usage, you’ll have a good idea of what size battery bank, and how many batteries you will need for your campervan electrical unit.
However, there are still more factors to consider, such as:
- How much sun will you be getting?
If you are traveling in a sunny location in the summertime, then your solar panels will be able to recharge your battery more frequently- meaning you can get away with a smaller battery bank.
However, if you’re going to be driving around in winter, or in a cloudy and shaded area, then your solar panels will not be able to frequently recharge your battery, and you will likely need a bigger battery bank to keep your campervan electrical unit up and running!
- Will you be driving a lot, or spending more time parked?
If your campervan electrical system includes the use of an alternator to recharge your battery, then the question of how much driving you’ll be doing greatly affects how large of a battery bank you’ll be needing.
If you plan to do lots of driving in your campervan, then your alternator will be able to recharge your battery more rapidly, and you won’t need quite as large of a battery bank.
Conversely, if you plan to execute more of a slow-travel lifestyle in your campervan, then your alternator will not be able to recharge the battery as frequently, and you’ll need a bigger battery bank to run your campervan electrics!
- What type of battery are you purchasing?
Battery type is mighty important, because the different types of leisure batteries each have different thresholds for how low their charge can get without ruining the battery.
- Lithium Batteries: Can be discharged all the way to 10%-20%.
- AGM Batteries: Can only be discharged to 50%.
- Gel Batteries: Can only be discharged to 50%.
Since AGM and Gel batteries should only be discharged to 50%, you will need to have a battery bank that doubles your daily power usage.
Therefore, if your daily power usage is 100ah, then you’ll either want a 100ah Lithium battery, or a battery bank of 200ah if your system uses a Gel or AGM battery.
However, if you opt for Lithium batteries, you won’t need to double your daily usage since they have a lower discharging threshold.
Part 3: Campervan Electrical System Components
Now that we’ve covered how a campervan electrical system works, here is a quick run-down of all of the different components that will go into your diy camper electrical system!
Keep in mind, every different campervan electrical system will vary slightly, but these components are generally what makes up the system:
- Battery: Where the power to run your loads is stored. The three main types of campervan batteries include Lithium, AGM, and Gel batteries.
- Solar Panels: Absorb the sun and create electricity to charge your battery.
- Solar Charge Controller: A solar charge controller regulates the flow of power from the solar panels to the battery, and prevents the battery from overcharging.
- Alternator: Charges the battery in a vehicle.
- Battery to battery charger: Also known as a B2B. A B2B gets wired to your alternator, and converts that electricity to a voltage that can charge your van’s leisure battery.
- Isolator: An isolator keeps your “vanlife” battery isolated from your “car” battery. This is important to ensure your “house” battery doesn’t kill your van battery by taking all of the power.
* There are three different types of battery isolators including solenoid, solid-state, and electronic isolators.
- Inverter: Converts your DC power to AC in case you have electronics that run on AC.
- Converter: Converts AC to DC. This will be necessary if utilizing a shore power charging source.
- Battery monitor: Monitors the charge levels of your battery. This is crucial to prolonging your battery’s life by keeping it above its recommended discharge level.
- Cut-off Switches: Used to cut off the flow of power to/from the battery.
- Wiring: What wires your entire electrical system together, and where the electrical currents flow through!
- Fuses: Fuses are crucial to a safe campervan electrical system. If too much electrical current is running through a wire to an appliance. Not only will this protect your electrical system, but it will also be crucial to preventing an electrical fire!
Part 4: Different Types of Campervan Electrical Systems
The Simple Campervan Electrical System on a Budget
If you’re looking to build a simple campervan electrical system on a budget, you can do so for roughly $600.
This system will need the following components:
- Inverter $35
- 100 ah Leisure battery $250
- Fuse box $20
- LED lights $56
- Battery isolation switch $16
- Fuses and cables $20
- 100 watt solar panel $100
- Solar charge controller $50
- USB sockets $30
The simple campervan electrical system is ideal for minimalist vanlifers who still want some off-grid power in their van.
With this setup, there is more than enough power to run lights in your van, charge some devices, and even run a small 12V refrigerator!
Full video → Simple but Ultra-Practical Van Conversion
If you’re looking for a more minimal campervan electrical system and only need to be able to power the basics like some LED lights, and maybe a small cooler, then the simple campervan electrical system should be sufficient for you.
However, if you’re looking for a slightly more sophisticated campervan electrical system that houses a bit more power, then I suggest you read on for the mid-range electrical system.
The Mid-Range Campervan Electrical System
While the simple electrical system covers the basics, the mid-range campervan electrical system will not only provide your van with more power, but with more solar and a larger battery, you will also be able to stay off-grid for longer periods of time!
A mid-range electrical system will cost roughly $1420, and require the following components:
- Pure sine inverter $300
- AGM battery $430
- Fuse box $20
- LED lights $56
- 12V LED strip lights $11
- Battery isolation switch $16
- Split charger $85
- Fuses and cables $20
- 3×100 watt solar panel $300
- Solar charge controller $130
- USB sockets $30
This electric system includes more solar power, and with a split charge relay, the battery can be charged while driving.
Just a little more power in a campervan conversion electrical system can open up more opportunities for your van conversion in terms of what electrical items you can run.
For example, with this setup you should have enough power to not only run lights and a small cooler, but also an electric water pump, a larger fridge, a Maxxair fan, all while staying off-grid for longer.
Full video → Family Camper Build by Motorhome Veteran
The High-End Off-Grid Luxury Campervan Electrical System
Now that we’ve covered the basic campervan electric system, as well as the mid-range, it’s time to bring out the big guns.
Introducing: the high-end campervan electrical system!
This high-end electrical system will cost roughly $4300, and includes the following components:
- 3000 watt 12V sine inverter $765
- 2 x 200ah Lithium Batteries $2000
- 4x 130 watt solar panels $800
- 90 amp btb charger $250
- Solar display $50
- Fuse box $20
- 2x LED spot lights $110
- 2 12V LED strip lights $22
- Battery isolation switch $16
- Solar charge controller $130
- Fuses and cables $50
- USB sockets $30
- Plug sockets $62
This bad boy can power not only lights, a fridge, and a fan, but also:
- A water pump
- A nespresso machine
- A milk steamer
- A blender
- A hair drier
- A heater
- All of the electronics for two full time working digital nomads!
The 3000 watt sine inverter is necessary to make the magic happen and power items that run off of 120AV like the coffee maker, hair drier, blender and milk steamer.
What’s also truly incredible about this campervan electrical system, is that even with such heavy DC and AV loads, this van is still capable of getting off-grid for several days at a time.
This campervan electric system would also be able to get a van without such a heavy AV load off-grid for weeks at a time. So even if luxurious campervan items aren’t your thing, this campervan’s electrical system can still meet your off-grid needs!
This really is the ultimate high-end campervan electrical system.
Full video → Incredible Luxury Van Conversion
Part 5: How to Install a Campervan Electrical System
Once you’ve decided how big you want your campervan electrical system to be, it’s time for the fun part- the installation process!
Step 1: Order ALL of your vanlife electrical pieces
Before you begin installing your camper van electrics, it is a good idea to order and purchase all of the pieces your system will need.
Some electrical pieces can be hard to purchase due to high demand, and the last thing you want is to have your conversion process delayed while waiting for the last piece of your electrical system.
Plus, having all of your electrical pieces all in front of you makes it easier to visualize what your system will look like, and makes the next step much easier.
Step 2: Create a wiring diagram
Once you have all necessary components of your campervan electrical system, you’ll want to create a campervan electrical system diagram that includes all of your wiring.
For your 12V loads, you’ll want the wires to be as short as possible. This is because the longer the current has to travel, the more power is lost.
However, any wiring to an inverter can be longer, as that wiring won’t suffer the same power loss as the 12V.
Step 3: Place your foundational components
After creating your wiring diagram, you should place all of the large foundational pieces in your campervan such as your battery, fuse box, inverter, solar panels, split charger, and any other big stationary components of your electrical system.
This provides a final opportunity to visualize the entire electrical system, and ensure all of the pieces are exactly where you want them.
Step 4: Make your live wires easily distinguishable
One incredibly crucial step in the campervan wiring process is to ensure your live wires are marked. Typically, the color red marks a live wire.
If no red wire is available in your area, it’s still an important step to mark your live wires, which can also be done with red tape!
Step 5: Complete Wiring
When all of your live wires are marked, your wiring diagram is completed, and you have placed the foundational components of your campervan electrical system, it is then time to wire it all together!
This is typically done with a method called crimping. Crimping is a method of connecting wires and creating a permanent electrical connection- and it should only be done with crimping tools, not pliers.
**To learn more about how to exactly install your campervan electrical unit, there are detailed instructional guides in my ebook, the Van Conversion Guide. This includes the nitty gritty on wiring, wire sizing, and everything you need to know to install your campervan electrical system all by yourself!
Not only does the ebook tell you exactly how to install a campervan electrical system, but it also comes with 25 how-to videos on how to convert a campervan.
Step 6: Perform a Safety Check
After everything in your campervan electrical system is installed and wired together, the next most important step is to perform a safety check over the entire system!
A faulty electrical system not only has the potential to damage your expensive electrical pieces, but it is also incredibly dangerous as it can cause electrical fires.
To protect yourself, and your equipment, it’s always prudent to have a professional electrician look over your campervan electrical system!
Part 6: Maintenance and Inspection
Just like how vehicles need annual inspections and maintenance to keep- their engines running smoothly, your campervan’s electrical system will likely need annual maintenance and to be inspected from time to time to keep it running smoothly and safely!
Some important things to check for in your campervan’s electrical system include making sure the fuses are functioning, all of the wires are still insulated, and there is no corrosion on the battery.
It is also important that all of the fittings, sockets, and switches are all in working order and don’t have any damage.
Regular maintenance and inspection can catch small problems early on, so you don’t run into any serious problems later down the road!
Campervan Electrical System Final Thoughts
There you have it, the ultimate guide to a campervan electrical system!
I hope that this guide answered any questions you may have about how a campervan electrical system works.
Whether you’re looking for an intricate, luxurious electrical unit, or more of a simple, bare-bones electrical system, I sincerely hope you now have some clear guidance on how to navigate choosing and installing your campervan’s electrical system!
While in this guide I’ve briefly touched on how to install your electrical unit, if you’re looking for a serious, in-depth, step-by-step guide on how to install your electrical system yourself, I have all of that and more in my ebook The Van Conversion Guide.
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