This guide goes over all the components of a van electrical system and the exact setup I use in my van. Van electrical systems can be as basic as using a portable power station or as in-depth as you can imagine. After eight months of living full-time in my van, this is the guide that I wish somebody had written for me.
I’ll be discussing the following areas:
- System #1: The Battery Bank
- System #2: Charging
- Solar Power Charging
- Alternator Charging (aka Battery-to-Battery Charging)
- Shore Power Charging
- System #3: Distribution
- The 12-volt DC and 120-Volt AC Distribution Systems
- The Power Inverter
- The Wiring Diagram
- Bus Bars
- The Fuse Block
- Wires and Cables
- Overcurrent Devices: Fuses and Breakers
- Assembling Your Van’s Electrical System
- Bonus: Portable Power Stations
Disclaimer: I am not an electrician. While many people educate themselves and build functioning van electrical systems on their own, electrical installations can be life-threatening if not done correctly. Do not take this guide as the final word for your installation. Read the manufacturer’s documentation for each device. Research online by posting questions to online communities. Consider hiring an electrician.
The electrical system for a van is broken down into the following three systems:
- System #1. The Battery Bank – How you store and monitor the electricity that you’ll use.
- System #2. Charging – How you charge the battery bank.
- System #3. Distribution – How you distribute electricity from your batteries and charging system to the devices that use it.
I’ll walk through each of these systems in detail below.
System #1. The Battery Bank
Your vehicle already has a factory battery that it uses to start the engine and power the vehicle electronics such as the radio, headlights, etc.
You’ll be creating a separate “house battery” system to run all your campervan electronics so you don’t risk running your factory battery dead. This avoids getting stranded somewhere because the vehicle won’t start.
Choosing a battery should be the first step in developing your van’s electrical system. Many other components will be dependent on what battery you choose.
First, you’ll want to determine what size battery bank you need. To do that you’ll calculate how much electricity you’ll be using. If you have some experience with van life already you might have an idea, but if you’re brand new it’s easy to calculate.
Before jumping into the calculations though, it’s important to understand the difference between 12-volt DC and 120-volt AC power.
12-Volt DC vs 120-Volt AC Power
When developing your van electricity system, you’re likely going to be dealing with both a 12V direct current (DC) and 120V alternating current (AC) system.
The electricity that comes from a battery in a van is direct current (DC) and the electricity from your house is alternating current (AC). This is important because different devices and appliances have specific needs. If a device requires 120V AC, it’s not going to work if you’re only providing 12V DC power. Laptops are a perfect example of this. They need 120-volt AC power to charge.
As you convert power from the stored DC power in your battery bank to AC power you will lose about 15% of your energy through the conversion. This is important so you can maximize efficiency by choosing devices that use DC power wherever possible in your van build.
Because boats, RVs, and vans use DC power, you’ll be able to find a lot of DC devices. In my van, I have the following DC devices:
You’ll be able to convert your van’s 12V DC electricity into 120V AC by using a power inverter (which I’ll talk more about below). For now, know that each device will use one or the other. The devices you commonly use in your house that you bring with you in the van are likely going to need 120V AC. The 120V AC devices I use in my van are:
- Macbook air laptop
- Ninja blender (smoothies are a necessity for my van adventures!)
- Portable projector
Now that you know the difference between 12V DC and 120V AC power, grab a copy of my battery bank calculator spreadsheet. Make a copy of this document and list out every device/appliance that will use electricity in your van.
After listing each device, add an estimate on how many hours you’ll be using that device per day. It’s a good idea to be conservative in your estimates so that you’re prepared for as many situations as possible.
For example, here’s what the list looks like for my van:
- Lights – 8 hours
- Fridge – 24 hours
- Fan – 14 hours
- Water Pump – 15 minutes (0.25 hours)
- Heater – 12 hours
- Laptop – 3 hours
- Cell Phone – 2 hours
- Portable Projector – 1 hour
- Blender – 5 minutes (.083 hours)
- Onewheel – 1 hour
Next, add the energy consumption of each device in the column titled “Watts of current”. Find this by looking at the manufacturer’s documentation, the device itself, or by doing a Google or Amazon search.
Before we start filling out this column it’s helpful to look at a basic electricity formula:
Power (Watts/W) = Current (Amps/A) x Voltage (v)
This is “Ohm’s law” and will help you to calculate how many watts a device uses. For some devices, you’ll find the energy consumption in wattage listed on the device. My blender says it’s a 700-watt device running at 120 volts. For other devices, the energy consumption will be in amps. This is when we need to use Ohm’s law.
For example, my Shurflo water pump runs at 5 amps and is a 12-volt device. Using Ohm’s law I can calculate the wattage:
5 amps x 12 volts = 60 watts
Another example is my Maxxair fan which runs at 0.65 amps average and is a 12-volt device:
0.65 x 12 volts = 7.8 watts
After finding the energy consumption of each device, we multiply the hours per day that we expect to use the device by the watts of current drawn. At this point, there is one extra calculation we need to make for each of the 120-volt devices.
Remember back when I said that we lose 15% of our power when we convert 12V DC power to 120V AC? For each of the 120V devices you have listed, you’ll need to divide them by 0.85 to account for this 15% energy loss.
This gives us a rough idea of how many watts of power we’ll be consuming on any given day. In my calculation, I estimated 1543.5 watts used daily.
Most batteries show capacity as Ah (amp hours) so we’ll return to Ohm’s law and get:
1543.5 watts = Current (Amps) x 12 volts
Divide both sides by 12 volts and get:
Current (Amps) = 1543.5 watts / 12 volts = 128.6 amps
This means that I’d be using roughly 128.6 Amp-Hours of power every day. Given that things rarely run perfectly, it’s a good idea to give yourself a buffer. I use a 170Ah (Amp-Hour) LiFePO4 battery in my van and it’s more than enough to run everything I need.
You’ll notice that you don’t see devices such as toasters, electric heaters, hair dryers, hot water boilers, or air conditioners on my list. These appliances draw a ton of power and will drain your batteries quickly. Anything that has a heating coil will draw a lot of power and is rarely worth using unless you’re connected to shore power (which I’ll talk about more down below).
The final step in determining which battery to buy is to consider the various types of batteries available on the market today. You’ll find Gel, FLA, AGM, and Lithium Iron Phosphate (LiFePO4) batteries in your research. I’m not going to go into a lot of detail about the various pros and cons of each because LiFePO4 batteries are far and away the best battery to get for van life.
They have a higher initial price point but will be more affordable in the long run because they have a longer life span than the others. Not to mention that a LiFePO4 battery can discharge faster and deeper than the other battery types. Gel, FLA, and AGM batteries should never discharge more than 50% so if you’re using 150 Ah of power per day, you’ll need 300 Ah of batteries, compared to a 150Ah LiFePO4 battery because they can discharge 100%. Additionally, LiFePO4 batteries are much lighter and take up less space.
Connecting Multiple Batteries
Many van lifers, myself included, get away with having a single battery to power their electrical systems. If you have massive energy needs and want to connect multiple batteries together, you can do it by connecting your batteries in a series or parallel.
Connecting batteries in a series keeps the amps the same across your batteries but steps your voltage up. Connecting them in parallel adds the amperage up and keeps the voltage the same. Most van electrical systems run on 12 volts, so you’ll use a parallel connection if you have more than one battery.
Creating a parallel connection is pretty straightforward. Connect the positive terminals together and the negative terminals together. So if you’re using two 100Ah 12v batteries, you now have 200Ah of battery power at 12v.
Battery & System Monitoring
While not required, having a way to easily monitor the status of your batteries and van systems is helpful. My Renogy solar charge controller (will talk about these later in this guide) came with a Bluetooth monitor. I can connect to it via my smartphone and see the status of my electrical system. I can check the battery level, how much power I’m currently pulling from the battery system, and how much solar power is being pulled to charge the system.
Some van lifers go with standalone systems such as the Victron Energy Battery Monitor. This provides a physical display that mounts inside your van for a quick status check and the ability to monitor more details via your smartphone. If you want to go all out, the Simarine Pico system can help you to monitor your water tank levels, the power draw of individual devices, and internal and external temperatures. It can even help you level your van if parked on uneven terrain!
With the battery bank system in place, the next section explains how to charge the batteries.
System #2: Charging
It’s a good idea to have multiple ways to charge your battery bank. This way you’re prepared for many situations you might find yourself in on the road. The three main ways of charging your batteries are:
- Solar power – Generating power from the sun.
- Alternator power – Charging your batteries from the alternator of your vehicle while it’s running.
- Shore power – Charging by connecting to the power grid.
Solar Power Charging
Solar power is a popular way of charging your batteries amongst van lifers. It’s affordable, effective, and environmentally friendly.
Solar panels operate by capturing particles of sunlight and turning them into electricity. Most van lifers will mount their solar panels on the roof of their van so they generate electricity anytime the sun is out. A few van lifers I’ve seen will carry solar panels around inside the van and set them out when they want to charge with them. This takes up precious space inside the van and takes time to set up and take down each time you want to charge. But if remaining stealthy is a priority for you this might make sense.
Solar panels have become much more affordable in recent years, but you still have some decisions to make. Whatever you choose, make sure you’re getting “9BB” panels as they have the best efficiency.
Flexible vs Rigid Solar Panels
Flexible solar panels can attach to a curved surface and are thinner, more stealthy, and easier to install. They’re also more expensive and less durable, meaning that they’re more susceptible to wear and tear.
Rigid solar panels are more durable, coming with an aluminum frame and a layer of tempered glass. They’re more efficient than flexible panels and more affordable. The downside is that they’re less stealthy, heavier, less aerodynamic, and need a more invasive installation on a flat surface. Despite this, rigid panels are the more popular option.
Polycrystalline vs Monocrystalline Solar Panels
Monocrystalline panels are slightly more efficient than Polycrystalline and won’t be as negatively affected by high temperatures. Yet they are more expensive.
Foldable Solar Panels
These panels are the ultimate in stealth van life but come at a cost as you need to set them up and take them down each time you use them. Coupled with being more expensive, they’re rarely the way to go unless stealth camping is a top priority.
Calculating How Much Solar You Need
If you’ve been following along and have calculated how much power you’ll be using per day with the battery bank calculator spreadsheet, this calculation is easy to do. You calculate your solar requirements based on the size of your battery bank. If you’re using a LiFePO4 battery, you can match the watts needed for solar to the Ah of your battery bank. For example, if you have a 200Ah battery bank, you’ll want to get at least 200 watts of solar panels.
Parallel vs Series Solar Panels
When installing more than one solar panel, you have a choice of installing them in parallel or in a series. This is similar to connecting more than one battery together. Installing solar panels in parallel will cause the voltage to stay the same but the current (Amps) will increase. Installing in a series will cause the voltage to increase and the current (Amps) will stay the same.
If you’re installing a 12-volt system, which is the most common setup for van lifers, you’ll want to install your 12-volt solar panels in parallel to maintain a constant voltage. Installing them in parallel also comes with the benefit of the panels being less affected by partial shading.
Partial shading is what happens when a portion of a solar panel gets blocked by something that is obstructing the sunlight. If you install your panels in a series, it can block the output of your entire solar array even if only a small section gets shaded. By installing your panels in parallel this won’t happen and you’ll only lose the output of the panel that gets obstructed.
To install panels in parallel, you connect all the positive lines together and the negative lines together using MC4 branch connectors.
Solar Charge Controller
The solar charge controller regulates the voltage and current that’s generated from your solar panels on their way to the battery bank. Without a solar charge controller, you’d overcharge and destroy your battery.
MPPT vs PWM Solar Charge Controllers
These are the two most common solar charge controllers on the market. MPPT (Maximum Power Point Tracking) is more expensive but also significantly more efficient. MPPT is the most popular solution for van life. Because of this, I’m not going to go into much detail about the differences and recommend you go with an MPPT solar charge controller.
Sizing Your MPPT Solar Charge Controller
Every MPPT solar charge controller gets rated for a maximum current (Amps). You want to make sure that the current (Amps) that is being generated from your solar panel array does not exceed the maximum for your charge controller.
To calculate this you’ll need to know how many panels you’re using and the current (Amps) of each panel. You can find how much current (Amps) your solar panels generate by looking at the specifications sheet, Googling it, or looking at the back of the panel. It’s required by law that the amperage gets listed on each solar panel.
For example, I have two 12-volt Renogy 160-watt panels that each generate 8.38A of current. They’re installed in parallel. Together they generate 8.38A x 2 panels = 16.76A of current.
A general rule of thumb is to have a solar charge controller that is at least twice the size of the current generated by your solar array. So, 16.76A of total current x 2 = 33.52A. I have a 40A solar charge controller.
Renogy has a variety of kits that include everything you need for a solar setup. Some include solar panels, a solar charge controller, cables, MC4 branch connectors, and a Bluetooth monitor. I have two 12-volt 160-watt flexible monocrystalline solar panels and a 40A solar charge controller from Renogy. The technology is moving so quickly that they no longer offer 160-watt flexible panels. Instead, they have these great 175-watt flexible panels.
Alternator Charging (aka Battery-to-Battery Charging)
The next method of charging the battery bank is through the alternator of the van. The van’s alternator generates electricity as you drive to keep the factory starter battery charged. You can tap into this system so that as you’re driving, you’re charging up your entire battery bank for your van’s house battery.
A B2B (Battery-to-battery) charger senses when your van’s engine is on and sends power to your battery bank. It’s also sometimes called a DC-DC or “DC to DC” charger. The larger the amperage rating of the charger, the faster it will charge your battery bank.
The B2B charger you choose should not exceed your van’s alternator’s available current or your battery bank’s maximum charge rate. Both of these capacities are in the manufacturer’s documentation. I have a 2018 Ram Promaster 2500 which has a 180A alternator, so any B2B charger needs to be below 180 amps. My 170Ah LiFePO4 battery has a maximum charge current of 85A. So I can use a B2B charger that is below 180A and 85A.
One final note about B2B chargers is that while you will generate charge current with the van turned on and idling, you’ll be generating more by driving down the road.
Shore Power Charging
The final charge method is shore power. “Shore power” is a term taken from the marine world where a boat would dock and plug into the electrical grid on land. In practical terms of van life, shore power means plugging into a 120-volt (15A) outlet you’d find in a house or a 30A or 50A outlet at a campground or RV park.
As with solar or battery-to-battery power, you need a way to regulate the current and the voltage of shore power so that you can use it to charge the battery bank. Besides that, you also need to convert the alternating current (AC) from the general electrical grid to direct current (DC) that’s used in the van.
The device you need to do this is an inverter/charger. A stand-alone inverter’s job is to convert 12-volt power to 120 volts and to turn direct current (DC) to alternating current (AC). Since your van’s electrical system is a 12-volt DC system, you’ll need an inverter if you want to run any 120-volt AC device in your van. I’ll talk more about stand-alone inverters later on in this guide.
An inverter/charger has the capabilities of a stand-alone inverter but adds the extra ability to convert 120-volt power back to 12 volts and AC back to DC. With this, you can charge your batteries when plugged into shore power. Van lifers who install an inverter/charger will usually mount a charging port to the side of their van so that they can run a shore power cord from an outlet directly to the side of their van.
In my van, I use a stand-alone inverter and do not have a dedicated shore power outlet. With a proper solar setup and a B2B charger, I generate more than enough power to keep my batteries topped up. I also do a lot of stealth camping and boondocking where there aren’t shore power outlets. This is what works for me but if you plan to spend a lot of time at campgrounds or RV parks, or want to use energy-hungry devices such as an air conditioner or electric heater, it might make sense for you to go with an inverter/charger setup.
A few final notes on shore power:
If you install an inverter/charger for shore power, get an appropriate shore power cord that matches the outlet. There are cords rated for 15A, 30A, and 50A. If you try to use a 15A shore power cord on a 30A or 50A outlet you’ll run the risk of melting the cord and/or creating a fire hazard.
An uncommon option for shore power is to use a gas generator. Running a gas generator creates 120V AC power so in theory you could connect a shore power cord from the generator to your inverter/charger. Gas generators are not common for van lifers. They are big and bulky and require you to carry gasoline and for the same price, you could get a better power solution through solar or a B2B charger. I’m adding it here as something to think about though because it is possible to do. You might run into somebody somewhere that has a gas generator that you might be able to use in a pinch.
The last shore power option is to use a smart car battery charger as a last resort. These chargers connect to your battery and then plug into shore power. In my van, I have solar power and a B2B charger permanently installed. As a last resort for shore power, I can manually connect my smart car battery charger instead of installing an entire inverter/charger setup. This makes my van more stealthy by not having an external charging port. Yet I still have the emergency ability to charge my battery bank through shore power. These devices don’t charge particularly fast, require you to manually connect it to your battery, and won’t allow you to run those energy-hungry devices, but it’s great to have as a last-resort option.
With the battery bank and charging systems in place, the last system is distribution.
System #3: Distribution
This final system is how you distribute the electricity from the battery bank to the various devices that use it throughout your van.
The 12-volt DC and 120-Volt AC Distribution Systems
As stated earlier in this guide, you’ll likely want to have a 12-volt DC and 120-volt AC system in your van.
Given that the existing battery bank and charging systems are 12-volt DC, that system is already covered. But what about the devices you want to use that need 120-volt AC?
The Power Inverter
Many devices that you commonly use in your home will need 120-volt AC. I use a laptop, a blender, a portable projector, and a Onewheel that all need 120-volt AC power. They will not charge through the 12-volt DC system alone.
This is where the power inverter comes in. A power inverter turns 12-volt DC power into 120-volt AC power so that I can use these devices.
You’ll find two different types of inverters on the market: pure sine wave inverters and modified sine wave inverters. I highly recommend going with a pure sine wave inverter. They’re more expensive but are worth it. A modified sine wave inverter can damage 120-volt devices that have switching power supplies such as laptops and smartphones.
Sizing Your Power Inverter
If your power inverter isn’t large enough your devices may not run properly. To determine the correct size of inverter you need you’ll want to find out the maximum load that all the 120-volt devices you expect to run simultaneously will draw. Be sure to check their peak power draw, not continuous, as some devices draw more power on startup. If you’re unsure how much power a device draws, consider getting a power meter to check it manually. For example, in my van, I use four 120-volt devices, listed here with peak power drawn:
- Macbook Air Laptop – 90 watts
- Portable Projector – 144 watts
- Blender – 700 watts
- Onewheel – 81.9 watts
This means that if I were to use all four of these devices at the same time, I’d be pulling 1015.9 watts from my inverter. It’s a good idea to give yourself a little bit of a buffer so consider adding 20-30% on top of this.
I have a 2000-watt inverter.
Power Inverter Final Thoughts
If you remember back in the section about shore power I talked about inverters/chargers. A “power inverter” is the “inverter” side of this. An inverter/charger has the functionality of an inverter and the ability to charge your batteries through a shore power outlet. A stand-alone inverter gives us this needed functionality of an inverter, without the ability to charge our battery bank via shore power.
It’s not recommended to run your inverter all the time because it’s not an efficient use of energy. You lose 15% of power through an inverter and inverters have a limited lifespan. Therefore, it’s a good idea to turn off your inverter when you’re not using any of your 120-volt devices.
Many inverters, such as my 2000-watt Renogy inverter, come with a switch included that you can mount that’s easily accessible. This avoids the pain of needing to climb back into your garage, where your inverter is likely mounted, to turn it on and off. If your inverter doesn’t come with a switch like this, you can buy one separately or get a ve.bus dongle that allows you to turn it on and off via Bluetooth on your smartphone.
The inverter or inverter/charger is the most dangerous part of your entire electrical system because of how much power it draws, so be extra sure that you get it installed correctly. If you’re unsure, don’t hesitate to hire an electrician to help you install it.
Recommended Power Inverters
I have a 2000-watt Renogy inverter and it has worked great. Renogy offers packages with various components in sizes of 700, 1000, 2000, and 3000 watts.
The inverter or inverter/charger is the last major device for your electrical system.
The Wiring Diagram
At this point it’s a good idea to create a wiring diagram to determine how all your devices will wire together. I recommend purchasing all your devices before starting to mount and wire them. By having all the devices on hand, you can determine where you can mount everything physically and still have space for wiring. It also gives you access to the documentation and manufacturer’s support when wiring everything together. Read all the manufacturer’s documentation for the devices and don’t be afraid to call their support line if you have any questions.
Here is a basic wiring diagram for my system:
All the pieces of your system need to get wired together in a specific way. You need appropriately sized wires and overcurrent devices (fuses and breakers).
In this section I’ll go through:
- Bus Bars
- The Fuse Block
- Wiring and cables
- Overcurrent devices: fuses and breakers
A bus bar allows you to make more than a single connection to the positive and negative terminals of your battery. Connecting a single wire from the battery terminal to a bus bar allows the bus bar to act as that polarity terminal for downstream devices. This keeps the wiring of your system much cleaner. You’ll likely want to have a positive and negative bus bar for their respective connections. In my wiring diagram, you can see a red and black bus bar connected directly to the battery.
The Fuse Block
A fuse block allows you to fuse several connections in a single place. Fuse blocks in vans are frequently used to fuse downstream 12-volt devices such as lights, fridges, water pumps, etc. I use a 12-circuit fuse box in my van. This means that I can fuse twelve 12-volt devices through this box.
A ground connection is a safety connection to flow excess surge power in a catastrophic event such as a lightning strike or connection with a high voltage line. This is a required safety connection. For van lifers, a ground connection means a connection to the chassis of your vehicle. Check your van’s manual for a list of approved ground points.
Wires and Cables
A wire conducts and transports electricity from a source to a destination, with plastic insulation for safety. A cable is multiple wires included together with sheath insulation to keep them together.
You’ll likely use wires for your battery, inverter, and charger connections. You’ll use cables for your DC load connections.
Wires come solid or stranded. Solid wires are most often used in homes and are not rated for vibration, so you should not use them in your van. You should get stranded wires with copper-tin plating when wiring your van’s electrical system.
Wires in the United States use the American Wire Gauge (AWG) rating. The AWG rating will tell you the greatest current that the wire can handle before it exceeds its temperature rating. If you go over this current, the wire can heat up and potentially catch fire.
The circuit length is the entire length of wire needed to complete the circuit. So it’s the entire length of the positive wire and the negative wire combined. So if your device is 10 feet away, the circuit length is 20 feet (10 feet for the positive wire and 10 feet for the negative wire).
Knowing the circuit length and maximum current, use this blue sea chart to determine the size wire you need to use. Find the length needed under the “10% Non Critical Voltage Drop” section on the left-hand side and match it with the maximum current the downstream device(s) will draw.
For example, my water pump draws 5 amps and is 10 feet away from the fuse block (so 20 feet of wire in total). Using the chart, I can see that I’ll need 16 AWG wires. For each side of my 60A B2B charger, I’ll need a 6AWG wire. You’ll likely use 2/0 AWG stranded copper wires for anything connected directly to the battery, to the bus bars, inverter (up to 3000 watts), and ground connections.
Any wire you get should be marine-grade and rated at 105 degrees Celsius. If you use a lower-rated wire it won’t be able to handle as much current and the blue sea chart won’t be accurate.
Overcurrent Devices: Fuses and Breakers
Overcurrent devices are the weakest point of an electrical circuit to ensure the safety of your system. They’ll prevent your devices from getting damaged and your wires from catching fire. Fuses and breakers both act as overcurrent devices to disconnect the circuit if too much current is flowing for too long.
A fuse is cheaper than a breaker but is not reusable. If too much current flows, the fuse will blow and you’ll need to replace it. A breaker does the same thing but instead works as a sort of on/off switch. If an overcurrent situation takes place, it will switch to the off position. Once the source of the overcurrent gets found and fixed, you can turn it back on and don’t need to replace the breaker.
An overcurrent situation can happen in a variety of ways, from an incorrect setting in your B2B charger or solar charge controller to a short circuit or faulty wiring. Every wire in your system needs to have an overcurrent device on the positive wire.
Do not buy cheap generic brands for fuses and breakers. This is one of the most important parts of your system and is crucial for your safety. Additionally, they’re not very expensive so give yourself some peace of mind and get quality overcurrent components.
To keep you and your system’s components safe, it’s essential to get properly sized fuses and breakers.
Sizing Fuses and Breakers
You’ll want to choose fuses and breakers that are below the max current rating of the wire and above the max current load the downstream devices will draw. You can find the max current rating of the wire under the “AWG Wire Specs” section of this West Marine post.
Here are a few examples:
My 60A B2B battery charger will draw 60 amps from the alternator and send it to the battery. So each side gets wired with 6AWG wire that, according to the west marine post, has a max current of 120 amps. So for each side, you’ll see in my wiring diagram, I use an 80A breaker. 80 amps are greater than the 60A of current the B2B charger will use. This allows the full range of functionality, but well below the 120 amps that the wires can handle. If there’s ever a malfunction in the system, the breaker will switch off, thus protecting the wires from overheating or any downstream device from getting damaged.
On the highest setting, my Maxxair fan draws 4A of power and is connected with 16AWG wires. I can see that 16AWG can handle a max current of 25 Amps so I use a 5A fuse in the fuse block.
The main wires connecting to my 2000-watt inverter use 2/0 AWG wire, which I can see can handle a max current of 330 amps. We know from Ohm’s law that 2000 watts / 12 volts = 166.66 amps of max current so I use a 300 amp fuse.
Assembling Your Van’s Electrical System
With everything purchased and your van’s electrical components mounted, you’re ready to wire everything together.
Disclaimer reminder: I am not an electrician and working with electricity is dangerous. There are a ton of great resources to reference online such as forums, Reddit, and Facebook groups if you ever have specific questions about your setup. That said, I’d recommend hiring an electrician to assist with the installation. With the knowledge gained in this article and everything mounted, wires, and overcurrent devices at hand, the installation shouldn’t take long and should be pretty affordable.
With that disclaimer out of the way, here’s the order in which I’d wire everything together:
You should wire your batteries together first and then work your way out from the batteries to the rest of your system. One way to do that would be:
- Ground your battery bank
- Wire your batteries together (if you’re using more than one battery)
- Wire your batteries to your bus bars
- Wire your bus bars to your fuse box. (Either directly to the fuse box or through your solar charge controller. Some solar charge controllers, such as mine, regulate the current out to the 12-volt devices).
- Wire your 12-volt devices downstream from your fuse box
- Ground your inverter
- Wire your inverter to the battery bank or the bus bars
- Wire your 120-volt devices downstream from your inverter
- If you have an inverter/charger you’ll also have a slot for 120-volt AC “In” power. This will get wired to your van’s external power inlet.
- Wire both sides of the B2B charger to the vehicle battery + bus bars (fusing the positive branches of each)
- Wire your solar panels together (probably in parallel)
- Wire solar panels to the solar charge controller (using a breaker on the positive branch)
Bonus: Portable Power Stations
If you’re not ready to install all the components I’ve gone through so far in this guide, there is another option.
Portable power stations are a van life electrical system in a box. They come in all shapes and sizes but generally include a battery bank, the ability to charge via solar, a wall outlet, or your vehicle’s power, and include a built-in inverter for 120-volt AC power.
For the price of one of these units, you could build a much more robust system manually. But if you want a stand-alone solution that works immediately out of the box, a portable power station might be for you.
This guide has described the major components of a van electrical system.
Now that your electrical system is in place, check out our ultimate beginner’s guide to van life.