Campervan Electrical Guide for DIY Van Conversion

The Basics of Electrical Systems for Camper van: A Guide to Designing Your Setup, from Batteries to Wiring Dimensions. We'll walk you through creating the perfect electrical system tailored to your vanlife needs and preferences!

INVÄNDIG INSTALLATIONELINSTALLATIONDIY CAMPERVAN

12/29/202410 min read

Electrical Systems for Campervan – Introductory Course 101

Master the Basics of Your Campervan Electrical System:

Choosing the right battery type for your campervan

a blue sign with white text
a blue sign with white text
MPPT och DC/DC laddare
MPPT och DC/DC laddare
silver MacBook beside battery charger
silver MacBook beside battery charger

Understanding MPPT and DC-DC chargers

How to charge your campervan batteries effectively

The difference between DC and AC appliances

1.1 - Battery Types, Voltage, and Capacity

When setting up an off-grid electrical system for your campervan, three key decisions await you:

  1. Battery Chemistry: Choose between lead-acid and lithium-ion batteries.

  2. Voltage: Should you go with a 12V or 24V system?

  3. Capacity: How many amp-hours (Ah) do you need to meet your lifestyle's power demands?

Let’s dive into these decisions step by step.

MPPT controllers and DC/DC chargers for vanlife
MPPT controllers and DC/DC chargers for vanlife
1.2 - Battery Types: Lead-Acid vs Lithium-Ion

While lead-acid batteries offer a lower upfront cost, they come with trade-offs like shorter lifespan and heavier weight. We recommend lithium-ion batteries (LiFePO4) for campervans, as their long-term benefits far outweigh their higher purchase price.

Comparison Overview:
Lead acid batteries
  • Twice the weight compared to lithium-ion batteries

  • 50% discharge capacity Lower

  • Lower purchase cost

  • Lifespan of 2-4 years

Lithium ion batteries (LiFePO4)
  • Lightweight

  • 100% discharge capacity

  • Higher purchase cost

  • Lifespan of over 10 years

1.3 – 12V vs 24V Batteries: Which Do You Need?

Off-grid campervan electrical systems typically run on either 12V or 24V batteries. Voltage can be thought of as the “speed” at which electricity flows through a circuit. For larger capacity systems, a higher voltage is usually more efficient.

12V Batteries:
  • Best for systems with under 400Ah capacity

  • Widely available with many options

  • Compatible with DC appliances without modification

  • Extensive online resources for installation

24V Batteries:
  • Ideal for systems exceeding 400Ah capacity

  • More compact and energy-dense

  • Slightly more expensive and complex to install

  • May require converters for certain appliances

1.4 – Determining Your Campervan’s Power Needs

Accurately calculating your power requirements starts with creating a detailed energy budget. While we recommend referring to our comprehensive guide, here are some general usage scenarios with corresponding battery recommendations.

Weekend Warrior / Part-Time Vanlifer – 200Ah

Ideal for users with basic DC appliances, such as a DC fridge, puck or strip lighting, Maxxair fans, and USB chargers. This setup may include a 1,200W inverter but is not designed for power-hungry appliances like induction cooktops or air conditioning.

Suggested Battery Options:
  • 2x 100Ah LiFePO4 Deep Cycle Batteries (12V) [Battleborn or Renogy]

  • 1x 200Ah LiFePO4 Battery (12V) [Victron or Renogy]

  • 1x 270Ah GC3 LiFePO4 Battery (12V)

  • 1x 100Ah Victron LiFePO4 Battery (24V)

1.5 - Full-Time Vanlifers - 400 Ah

The two most common battery voltages in off-grid electrical systems for camper vans and motorhomes are 12V and 24V. In simple terms Voltage, it represents the "speed" at which electrons flow through a circuit generally, the larger your system’s battery capacity, the higher the voltage you’ll want. If you’re curious about the differences between 12V and 24V, we’ve written an in-depth guide on the topic.

12-Volt Batteries:
  • Best for systems with less than 400 Ah capacity

  • A wide range of manufacturers to choose from

  • No modifications are needed for DC appliances

  • Plenty of online resources for installation guidance

24-Volt Batteries:
  • Ideal for larger systems exceeding 400 Ah capacity

  • A more compact and energy-dense solution

  • Slightly more expensive and complex to wire

  • May require converters for certain appliances

Lithium-Ion Batteries (LiFePO4) for Campervan Build
Lithium-Ion Batteries (LiFePO4) for Campervan Build
1.6 - Luxurious Vanlife Without Compromises - 600 Ah or More

If you’re aiming for all the comforts of a home connected to the grid, you’ll need at least 600 Ah of battery capacity. This allows you to run air conditioning, cook with an induction hob, heat water, and power a heater without worries. For such a robust battery bank and high daily usage, it’s crucial to ensure rapid recharging via your alternator and significant solar power! Full-time vanlifers in northern regions, where sunlight is scarce in winter, often opt for this setup.

Recommended Batteries for High Capacity Systems:
  • 270Ah GC3 LiFePO4 Deep Cycle Battery (12V)

  • 330Ah Victron LiFePO4 Battery (12V)

  • 200Ah Victron LiFePO4 Battery (24V)

1.7 - How to Charge Your Camper Van Batteries

Running out of power on the road is a nightmare for any vanlifer. To avoid this, we recommend diversifying your charging options. For those living in their vans full-time, having all three of these charging methods is ideal:

  • Solar Power

  • Alternator Charging

  • Shore Power

Solar Power - The Holy Grail of Off-Grid Vanlife
A comprehensive energy budget will help you determine how much solar capacity you need to supply your camper van's batteries. Spoiler: It’s worth maximising your solar panel size to make installation easier and more efficient.

For systems over 300 W, opt for larger panels like 175 W, 200 W, or even higher instead of smaller 100 W ones. On our van, Rover, we use two 370 W residential-grade panels. Larger panels simplify wiring and mounting, and you can often fit even more solar on your roof. However, bear in mind that increasing solar capacity might limit your roof space, so plan your layout carefully.

1.8 - Alternator Charging with a DC-DC Charger

Charge your camper van batteries while driving by installing a DC-DC charger. This is essentially free power, as you can time your journeys to recharge when solar isn’t sufficient. For winter, when daylight is limited, maximising power input is crucial. Use the following guidelines to decide if you need one or two Victron Orion 30A DC-DC chargers:

One DC-DC Charger:
  • For weekend warriors with smaller systems

  • If you have less than 200 Ah lithium batteries

  • If your vehicle’s alternator is 160 amps or less

    _ _ ___ _
Two DC-DC Chargers:
  • For full-time vanlifers or luxurious setups

  • If you have over 200 Ah lithium batteries

  • If your van has dual starter batteries

  • If you have a high-output alternator or dual alternators

_ ___ _ ___ _
Shore Power via an Inverter Charger

You can also charge your batteries from shore power using an inverter charger. Here are our favourite models:

  • Victron Multiplus C 12V, 2000W, 80-50 amp Inverter Charger

  • Victron Multiplus II 12V, 3000W, 120V-50 amp Inverter Charger

    • Slim design, weighs 22 kg

    • Dual 50 amp AC outlets

    • Charges 12V batteries up to 1440 W (120 amps)

    • This is the one we use in our van!

    • View full specifications here.

Alternator Charging with a DC-DC Charger for Camper van
Alternator Charging with a DC-DC Charger for Camper van
2.1 – Two Ways to Use Your Camper Van’s Batteries (DC vs AC Power Consumption)

When planning your campervan's electrical setup, one of the biggest decisions you'll face is whether to prioritize 12V systems or incorporate mains (AC) power. While mains-powered appliances are often cheaper because they’re less specialized, 12V appliances—such as 12V fridges designed specifically for campervans—are generally more efficient and tailored for off-grid living. Put simply, there are two ways to use your camper van’s batteries:

  1. Via 12V (or 24V) direct current (DC)

  2. Via 220V - 230V alternating current (AC).

Note: In the UK and Europe, the standard AC voltage is 220V, unlike the 120V used in North America. Always check your country’s AC standard before starting your build!

2.2 – Direct Current (DC) Appliances in a Camper Van

DC power is the backbone of your off-grid electrical system! It powers most of the permanently installed systems in your van. DC is more efficient than converting to AC and back, so as many appliances as possible should run on DC power.

We recommend designing your camper van to be entirely self-sufficient on DC power (yes, even DC mini-fridges!). This reduces the need to keep your inverter running constantly, which can draw significant power (10–30 W depending on the model). Keeping your inverter off when not needed will save a lot of energy.

Common DC Loads in Camper Vans:

  • 2x Maxxair fans

  • Dometic CRX 110E refrigerator

  • LED puck lights

  • Water-resistant LED strip lights

  • Water pump

  • Electric ball valve

  • Acuva UV water filter (Read our review of the water filter here!)

  • Compost toilet (Read our review here!)

  • LED reading light

  • Gas heater

  • USB charging socket

  • RV fresh/grey water tank heater

2.3 – AC Appliances in Your Camper Van

While your van can run entirely on DC power, adding AC appliances opens up a whole new world of comfort and convenience, making vanlife feel much more like home. AC power covers anything you plug into a standard outlet. Below are some of our favourite road-trip appliances!

  • Foldable Electric Kettle

  • Induction Hob

  • Hand Blender

  • External Monitor

  • Laptop Charger

2.4 A Guide to Efficient Energy Use

When you are planning your campervan's electrical setup, one of the biggest decisions you'll face is whether to prioritize 12V systems or AC power. While mains-powered appliances are often cheaper because they’re less specialized, 12V appliances, such as 12V fridges designed specifically for boats, trucks and campervans are generally more efficient and tailored for off-grid living.

Our Setup: 12V All the Way
In our fairly basic campervan, we rely almost entirely on 12V systems. Our lights, diesel heater, and multi-cigarette sockets all run on 12V. When we plug into a mains power source, our battery charger kicks in to keep my leisure battery topped up. While we also have a split charge system, we don’t always use it, and we haven’t added solar panels yet.

When I do use mains power, I have three mains sockets available:

One powers my battery charger.
The other two handle high-energy appliances my battery bank can’t support, like an electric fan heater or a hot plate for cooking. For most cooking, we usually stick to a traditional alcoholic stove/burner.

Why Stick to 12V?

Whenever it's possible, sticking to 12V for your campervan’s power system is the most efficient option and here are some reasons:

Energy Efficiency: Voltage conversion from DC to AC through an voltage conversion causes energy losses, typically around 20% to 25%. Even high-end inverters with 85% efficiency waste energy. For example, to power a 1200Wh load through an inverter, you’d need over 1400Wh of battery capacity. By staying with 12V, you only need 1200Wh of battery capacity for the same load.
Safety: Working with 12V wiring is safer and simpler than dealing with 240V AC systems, especially in vehicles. If you’re plugging into mains power occasionally, it’s crucial to use inverters correctly and safely to avoid accidents.
USB Power Loss: USB outlets for charging devices often suffer from inefficiencies too. High-quality USB chargers can be up to 80% efficient, while inexpensive ones are often around 50% efficient. Sticking with the native voltage of your battery bank unless absolutely necessary(charging a phone/tablet/laptop) is the way to go.

Should I choose a modified or pure sine wave inverter?

The short answer is that a pure sine wave inverter is always better than a modified sine wave inverter – they can power all types of electronic devices. However, they are a bit more expensive, and sometimes a modified sine wave inverter will do. Here’s a breakdown of how it works and how to choose the right one.

Why a pure sine wave is a safe bet A pure sine wave is the same kind of power we have in our homes, whereas a modified sine wave is "square".

A pure sine wave compared to a modified sine wave A pure sine wave can power virtually all types of devices, while a modified sine wave works poorly with several types of equipment. In the worst case, the device may even break if powered by a modified sine wave. Some examples of devices that a modified sine wave is not suitable for include:

  • Stereo/Hi-Fi systems – the sound quality is compromised

  • Most modern electronic devices (e.g., computers & TVs) – may get damaged


Purity has a scale Not all "pure" sine waves are equally pure. They can be more or less rounded. Purity is determined by measuring the ratio between the sum of the harmonics and the fundamental frequency (50 Hz).

Conclusion The conclusion is simple

If you’re building a campervan, try to minimize your reliance on inverters and focus on running appliances directly off your 12V battery bank. This setup reduces energy waste, simplifies your wiring, and keeps your van safer overall.

Safety First: Stick to 12V where possible. It’s safer and easier to work with compared to mains voltage. Keep It Simple and try to build with 12V appliances to maximize efficiency and safety in your campervan's electrical system.

Minimize Inverter Use: Every time you convert power, you lose energy. Only use an inverter for appliances that absolutely require it.
Think Long-Term: Investing in high-quality components like inverters and USB outlets can save you energy and frustration down the road.

By understanding the trade-offs between 12V and mains systems, you can design an energy setup that meets your needs while keeping your campervan efficient, safe, and ready for adventure.

Also when you are buying an inverter, you should choose one with a pure sine wave. It works with many more devices, and you don’t have to worry about your gadgets getting damaged when you plug them in. If you only need to charge your phone and plug in a tool, a modified sine wave will work fine – but who knows what you’ll want to connect in the future?

Our FREE Electrical System Blueprint

Your camper van’s electrical system is likely to be one of the biggest investments in your build. To make informed choices and create a reliable setup for off-grid living, it’s essential to understand your needs and options thoroughly. Review the electrical system overview above during your planning phase. Once you're ready to start the installation, check out our detailed posts on setting up your system!

If you’re unsure about any aspect of your build, don’t hesitate to book a Virtual Build Consultation with us for personalised advice.

Additionally, we’ve digitised our electrical system blueprint, which you can download here:

Additional Camper Van Electrical System Guides

To further support you during your van conversion, we’ve written a range of in-depth guides about camper van electrical systems, including:

  • Comprehensive Solar Power Guide

  • Battery Selection Guide

  • DIY Battery Cable Guide

  • 12V vs 24V Systems for Camper Vans

Each guide is designed to make complex electrical topics easier to understand, helping you build a safe and efficient off-grid power system.