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DIY Camper Van Electrical System

A Step-By-Step Electrical Wiring Guide For Van Life

Feeling overwhelmed about building your camper van’s electrical system? You’re not alone. For many, installing the electrics is often the most challenging part of a van conversion.

This step-by-step electric system guide for camper vans & RVs covers everything you’ll need to know to assemble your own van electrics, including:

We also provide a 100% free electrical wiring eBook, which you can find available for download at the end of this guide.

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Post Archive (Electrical)

For specific tutorials, scroll through the different posts we have below regarding building a camper van electrical system.

All About Batteries

Three lithium batteries in a camper van

The batteries are the “heart” of your camper van’s electrical system. They supply the power required to keep all your devices running. These devices include your lights, fan, smartphone, laptop, and more.

So to say that batteries play an ‘important’ role is a massive understatement.

They’re mission critical!

Therefore, if you want to build a robust electrical system that adequately meets your power demands, deciding the right type and size of batteries is an essential first step. Keep reading to learn how to select the best batteries for your camper van.

1.1 - Battery Options (AGM vs Lithium)

There are two different battery chemistries being used today that are popular among the van life community: lead acid (AGM) and lithium-ion (LiFePO4). Each battery type has their pros & cons.

AGM

Lithium

Initial Cost

Weight

Usable Energy

Lifespan

Robustness

To learn more, we cover the topic of battery chemistries in our post: AGM vs. Lithium.

However, because batteries are critically important to powering all our electrical devices, we believe lithium batteries are the best choice. Learn why lithium batteries are worth it for van life.

1.2 - How Much Batteries Do You Need?

How many batteries do you need? The answer is that it depends on what electrical devices you want to power. And, electrically-speaking, no two camper vans are the same.

Some van conversions have every electrical device known to mankind and will require a large battery bank to power all this equipment. Other camper vans have only modest electrical needs.

So to calculate how much battery you’ll need, you’ll want to following these steps.

Banner image for our post to calulate how much batteries you'll need for your camper van's electrical system

Still confused? This exercise can be time intensive. That’s why we dedicated a separate post teaching  you how to calculate your ideal battery size.

12v System

Now that you’ve selected your batteries, you’re ready to put together your camper van’s 12v electrical system. This section includes connecting the batteries all the way to your individual 12v devices, like the lights, vent fan, and USB ports.

By the end of this section, you’ll have a system that is equivalent to the 12v wiring diagram below.

12v Wiring Diagram For Camper Vans & RVs
Complete 12v wiring diagram

2.1 - Wiring Multiple Batteries: Series vs. Parallel

Remember that when you connect multiple batteries in series, you are adding the voltages of each battery together while keeping the total amp-hours the same. You will likely NOT want to do this.

Wiring batteries in parallel instead keeps the voltage unchanged while adding together the amp-hours. This is what you LIKELY want to do.

This is because most deep-cycle batteries are 12v and we want to build a 12v system while expanding our battery bank size (amp-hours). Therefore, wiring in parallel is the ideal option for most of us.

2.2 - Recommended Wire Sizes For A 12v System

Getting the exact wire sizes you ‘technically’ need involves lots of different calculations involving current flows and power consumption. But we like to keep things simple and that’s why we recommend only two different wire sizes for your entire 12v system build.

  • 2/0 AWG – To wire the batteries together and to connect them to the 12v panel.
  • 14 AWG – To wire all your 12v devices to the 12v panel.

For more detailed information on recommended wire sizes for your entire van electrics build, check out our wire size recommendation post.

2.3 - Step-By-Step Wiring Guide

If you’re ready to piece together your 12v system, check out our 12v installation guide. We breakdown the build process into three easy-to-understand parts.

  • Part 1: Wiring batteries to bus bars
  • Part 2: Wiring bus bars to 12v panel
  • Part 3: Wiring 12v panel to 12v devices

In our guide, we include all the materials & components required and take you, step-by-step, through the entire process.

We also have a separate post detailing how to wire LED lights in a camper van (with switches).

2.4 - Free Electrical Wiring Diagram eBook

To save for later, download our electrical wiring diagram eBook. It includes many of the same diagrams you’ll find in our posts. Each product and component image is clickable, taking your straight to the item’s Amazon page for easy purchase.

The eBook is 100% free. No pesky email signups or up-sells.

Solar Panel System

Planning to travel off-grid? Then integrating a solar panels with your van’s electrical system is a must. In fact, solar power is the #1 way we charge our batteries.

But wiring a solar panel system to your camper van electrical system can feel like a daunting task. There’s just even more wires, components, and calculations involved.

That’s why we think that there’s no better place to start than with our complete camper van solar system guide. In our guide, we discuss:

  • Calculating how much solar you need
  • Series vs parallel panel connections
  • Ideal wire sizes
  • Fuses & charge controllers
  • How to mount panels on your roof
  • Step-by-step wiring guide

We’re positive that our guide will get your van conversion from ‘zero to solar’ in no time.

Check it out!

3.1 - How Much Solar Do You Need?

Calculating how watts of solar panels you’ll need ultimately depends on the total daily power consumption of all your electrical devices. The more power you require, the more solar watts you’ll need.

However, if you followed our battery sizing guide, then calculating your solar size requirement is a simple calculation. That’s because your battery size is already based on your total power consumption.

For more in-depth information, read our post: How To Size Your Solar Panel System

3.2 - Solar Wire Size Recommendation

Under most situations, 10AWG wire is the perfect wire size for a solar system. But you should double check.

The best wire thickness for your solar system depends on two factors.

  1. Total array size: How many total watts do you have?
  2. Panel connection type: Are you panels connected in series or parallel?

Selecting the correct wire thickness is important to keep your solar panel system safe. If you’re wires are too thin, the wires can overheat and potentially catch on fire.

We want to prevent that!

For more a detailed breakdown of what you’ll need, check out our post: Recommended Solar Wire Sizes.

By the end, you’ll know exactly which solar wire size you’ll need.

3.3 - Step-By-Step Solar Wiring Guide

For a non-nonsense tutorial that tells you exactly what you’ll need, check out our RV solar wiring guide. There’s lots of great content that stems from that post and will get you on your way to piecing your entire system together.

To save for later, download our solar wiring diagrams eBook. It’s got:

  • Intuitive diagrams
  • Product & component lists
  • More reading for additional learning

It’s also 100% free. No catch.

Inverter System (120v)

If you plan to charge laptops, power a blender, or run any other standard household device, it’s necessary to install an inverter that will convert the 12v from your batteries to a usable 120v for those specific devices.

Based on installation difficulty, there are three different types of inverters you can choose from:

  1. Easiest: Get a portable inverter that plugs into a 12v socket
  2. Medium: Get an inverter with built-in sockets. Like this AIMS inverter.
  3. Hardest: Get an inverter that requires you to install your own sockets.

We went with option #3 so that we could install wall socks in our camper’s plywood walls. But if you want a more simple electrical system, option #1 or #2 are great, too.

4.1 - What Size Inverter Do You Need?

The inverter size you’ll need depends on what you intend to power. This means you’ll need to know the power consumption of all your 120v devices.

If all you want is to charge your laptop and a drone battery, a small portable inverter would be sufficient for your needs. But if you want to power something larger like a hair dryer or hot water tank, you’ll need a larger inverter.

To calculate your ideal inverter size:

  • Step 1: Identify the 120v device with the largest power consumption
  • Step 2: Double the rated watts of this device and round up to the nearest 1000.

For example, a Bosch hot water heater is rated at 1,440w. Doubling the wattage gets you 2,880w and rounding up gets you 3,000. So you would need a 3,000w inverter to successfully power this water heater.

4.2 - What Is An Inverter/Charger?

Unlike a standard inverter, which only converts 12v to 120v. an inverter/charger combo unit has the added ability to charge your batteries from shore power. This means the inverter/charger can accept a 120v charge and convert it to a 12v flow, which your house batteries can accept.

This is a very useful capability, but it does make the unit more expensive.

We have an inverter/charger unit in our van and while we do not use it very often, being able to charge our batteries from shore power has come in handy.

4.3 - Inverter Wiring Diagram & Installation

If you’re ready to install, check out our camper van inverter installation guide. It’s got lots of great content teach you how to:

  • Connect the inverter to the batteries
  • Wiring to a ground point
  • Connect to shore power (if it’s an inverter/charger)
  • Wire to electrical outlets

Included in our guide are all the wires and little components you’ll need to successfully complete your inverter installation.

By the end, you’ll have an inverter system that looks just like the diagram here.

Inverter Wiring Diagram For Camper Vans & RVs (Complete)
Inverter System Installation

We also provide all our inverter diagrams in our electrical wiring eBook.

Charge While Driving

As important as solar is to an van electric system, relying on solar power 100% is not recommended. There are simply too many scenarios where your solar panels cannot sufficiently charge your batteries. That’s why it’s critical to also set your electrical system up so that your house batteries can be charged while you drive.

Caveat: The method and components we used are intended for those with lithium campervan batteries.

5.1 - Materials List

Product Purpose Where To Buy
250amp Fuse Protects electrics from surges, Amazon-Button
Fuse Holder Houses the 250amp fuse. Amazon-Button
Battery Isolation Manager Regulates the voltage from vehicle battery to camper batteries. Amazon-Button

5.2 - Step-By-Step Guide

1. Vehicle Battery To Fuse

Locate the positive terminal of your vehicle’s starting battery and run a short piece of 2/0 wire to a 250amp Fuse (and Holder).

In our case, we tied down the fuse holder to a spot under our van’s hood.

The purpose of this fuse is to protect the batteries from unexpected electrical surges.

2. Fuse To Lithium Battery Isolation Manager

Next, run another short piece of 2/0 wire from the fuse to the “Batt Chassis” post on the lithium battery isolation manager (BIM).

This isolation manager is the brain of the battery charging process and cycles the charging process on and off to prevent overheating of your vehicle’s alternator.

3. Connecting To Our Campervan Batteries

With 2/0 wire, connect the “Batt Coach” binding post of the BIM to the positive bus bar.

4. Ignition Connection & Grounding

In order for the battery monitor to know when the ignition is turned on, we hooked a 12awg wire from the BIM post labeled “Ign” to our van’s fuse box under the hood. We found an unused fuse socket that is ONLY activated when the van is turned on and stuck our 12awg into the socket.

To ground the whole system, take another 12awg wire and connected from the BIM’s “Gnd” post to a ground point on the van’s chassis.

When finished, the entire connection should look like the diagram below.

Camper Van Electrical System - Fig 6.1: Connecting House Batteries To Vehicle Starting Battery
Fig 6.1 - Connection To Vehicle Starting Battery

Wiring Diagram eBook (FREE!)

All of our instructions and wiring diagrams can be found in our camper van electrical wiring eBook that we put together for camper van conversions and RVs.

Inside our eBook, you can find:

  • Detailed, intuitive wiring diagrams
  • Recommended products (and even tiny components)
  • Clickable product images for more info and purchase
  • Resources for additional reading & learning

And the eBook is 100% free. Check it out!

Recommended Tools

When building an electrical system for your van, there are several tools that you’ll use over and over again. We list the 5 most commonly used tools below.

Product

Purpose

Where To Buy

2/0 Wire Cutters

Cuts through thick 2/0 wires.

Hammer Lug Crimper

Crimps copper lugs onto 2/0 wire ends.

Heat Gun

Activates heat shrink over wire ends.

Wire Multi-Tool

Cuts, strips, and crimps 10-16AWG wires.

Multimeter

Checks electrical system for functionality.

Maintenance Tips

Campervan Electrical System Installation - Battery Monitor

Just because you’ve finished building your camper van’s electrical system doesn’t mean the work is over. While traveling, it’s a good idea to keep up with proper maintenance of your electrical system.

This usually involves the following two areas.

8.1 - Best Battery Charging Techniques

Knowing how to properly charge your batteries is crucial to the long-term health and lifespan of these batteries. Spoiler alert: Different battery chemistries require different charging strategies.

Did you know:

  • Traditional AGM batteries should not be discharged lower than 40%?
  • Lithium batteries don’t like to be constantly kept at 100% charge?

Doing either of the above can significantly reduce the lifespans of those batteries. And we’ve seen multiple van lifers throw away almost new batteries simply because they didn’t understand proper battery charging & discharging techniques for their own batteries.

If you’re interested to learn more on how to maximize your battery’s lifespan and prevent unnecessary, additional battery expenditures, read our battery maintenance article.

8.2 - Make Sure Screws & Bolts Are Tight

Because of all the vibrations that our camper van incurs due to driving, all the screws and bolts in our van electrics become loose over time.

Of course, we want everything in our van generally being held tight together, but loose electrical components is also a fire hazard. Short circuits in a camper can, and do, happen.

So once a month, it’s a good idea to take a screw driver and a ratchet and make sure every screw and bolt is fastened tightly.

FAQ

Eh, not really. You definitely do not need a degree in electrical engineering to complete your own campervan electrical system. You can simply follow our free  PDF guide and be one your way. But if you’re interested to learn more, knowing basic electrical jargon can help you better understand what’s going on “under the hood”.

Yes, you can! We also had zero experience in electrical systems and managed to piece together quite a complicated system that has served us well for over 2 years. Our step-by-step electrical installation instructions can get you from start to finish.

We understand there are ways to calculate the ‘proper’ wire size you need for each type of electrical device you want to run based on that specific device’s power consumption. Frankly, it’s a waste of time.

We list the only four wire sizes you need for your electrical system.

  • 2/0 AWG To connect the batteries to the bus bars, inverter, and vehicle starting battery.
  • 10 AWG For all solar panel connections.
  • 12 AWG For all 120-volt connections, if any.
  • 14 AWG For all 12-volt devices.

Unlike a regular house, a vehicle doesn’t have normal “ground” points. In the case of campervans, it is OK to ground your electrical devices to the vehicle’s chassis. In our Ford Transit there are multiple “ground” chassis connection points.

 

Ford Transit ground points on the chassis

 

The above diagram shows all the possible chassis ground points on a Ford Transit van. We primarily used 31 & 35 for our ground points.   

Having the option to connect to shore power is convenient. Though we do not often stay at pricey RV parks with supplied shore power, we do on occasion stay at these parks for 1-2 weeks to rest and recoup. Being on the road 24/7 is draining! And we’ve found that many RV sites are quite shaded, which is nice, but is terrible for harvesting solar power. In the shade, our batteries will reach 0% in 4-5 days. So being able to connect to shore power has given us more flexibility.

100% don’t try to save money on batteries. They are the life blood of your campervan electrical system. And so much of ‘van life’ depends on electricity. Even if you can’t afford fancy lithium batteries, as best as you can, get good quality AGM batteries. And while battery quality is important, battery QUANTITY is just as crucial. Read our article to figure out what size battery bank you require. Undersizing your battery bank will lead to faster battery degredation and wasting money to purchase new batteries.

A Rewarding Experience!

We hope you learned enough from our camper van electrical system article to be able to build your own electrical setup.

When we first started, the whole process was completely overwhelming. There were so many components to purchase and so many steps to complete. But we took our time and made sure each step was done to the best of our abilities.

In the end we found the entire process of building our own electrical system in our van conversion both completely doable and a highly rewarding process!

If you have any questions or comments about our van electrics article, please post a comment below or send us an email through our Contact Form.

Thank you!

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