Campervan electrics:
a beginners guide

When we started planning our van, we discovered, that finding reliable and comprehensive information about the electrical system in a van can be quite tricky.

Now that we’ve got it all figured out, set up and been using it for more than three month full time, we feel accomplished enough, to share our experiences with you. Moreover we have a technical background and received additional support from an electrical engineer.

We want to share our knowledge and created this overview on how you can start planning an electrical setup for your campervan covering the seven most important topics:

  • CIRCUIT DIAGRAM
  • CALCULATE ENERGY DEMAND
  • BATTERY TYPE AND SIZE
  • RECHARGE BATTERIES
    – B2B charger
    – Shore power
    – Solar power
  • AC INVERTER (230 or 120 V)
  • CABLES & CONNECTIONS
  • FUSES, CIRCUIT BREAKERS & SWITCHES

CIRCUIT DIAGRAM

A circuit diagram is a representation of the connection of all the electrical components in your van. It also illustrates where you put switches and fuses and is the best way to plan out the electrical system. You don´t need a special software to create a circuit diagram. A pen and a paper are sufficient 😊

Throughout this beginners guide about campervan electrics you will learn about all the single components you need to build your own circuit diagram.

As an example you can also download our circuit diagram:

circuit diagram

CALCULATE ENERGY DEMAND

Why should I calculate the energy demand?

The calculation will help you to choose the right type and size of all components for your specific need. You don´t want to run out of electricity on the road again and again, but you also do not want to carry an extra 100 kg of electrical setup around the world that you don´t need. Engineers call this “right-sizing”.

How do I calculate my energy demand?

Imagine yourself living in your future van. What kind of activities will you be doing, that need electricity? Now is the right time to sit down and list all the electrical devices you will operate in your van. Here’s a list of potential electrical consumers as a starting point:

  • Lights
  • Fridge
  • Waterpump
  • Cooktop
  • Blender
  • Coffeemaker
  • Kettle
  • Heater
  • Boiler for hot showers
  • Air Condition
  • Fans
  • Phone/Tablet
  • Laptop
  • Monitor/TV
  • Bluetooth speaker

Create a table of all your consumers that looks like the one below. We will then describe how to calculate all the relevant data to determine your future energy consumption in the van.

table of consumers

After listing your devices, add the quantity and find out the electrical power in Watts (W) for each line item. Especially when you plan to use an electric fridge this value can be hard to find – sometimes you even have to contact the manufacturer. Add the voltage they will operate on (12/24 V or 230/120 V)  and calculate the current in Amps using the formula below. Be aware that the power will be provided by the battery. Therefor, you have to insert the voltage of your battery (12V or 24V) in the formula – also for the consumers with 230V or 120V!

In a next step make an assumption about the hours each device will run in your van per day. Calculate the consumption per day in AmpHours (Ah) for each line of the table using this formula:

consumption per day

Finally, you can complete your table by summing up your electrical consumption over all devices . To cater for losses in the electrical system multiply your result with a factor of 1.1. In the table above the final consumption including losses is: 210 Ah per day

You will need your value later in the design of your campervan electrics system.

BATTERY TYPE AND SIZE

There are four battery types that are used in campervan electrics:

  • Wet batteries
  • Gel batteries
  • AGM batteries
  • Lithium-Ion batteries

We want to focus on the two types of batteries that are most commonly used in van conversions nowadays: AGM and Lithium-Ion batteries (LiFePo4).

Both types have their pros and cons:

AGM batteries

are comparably inexpensive (around 200 € for 100 Ah (Amp hours)) and they don’t require a special charger. On the downside they are a lot heavier than Lithium Ion batteries and need to be recharged more often, as discharging them to less than 40% of their capacity can drastically decrease their lifespan or even destroy the AGM battery. To not risk a loss of capacity you should also avoid leaving them in a (partly) discharged state over a longer period of time.

  • inexpensive
  • no special charger needed
  • high weight
  • only 50-60% of capacity can be used

LiFePo4 Batteries

are the expensive choice (100 Ah will cost you approximately 800-1000 €). Additionally, all chargers you are going to install in your van have to be able to charge this type of battery. They do come with many advantages however: They are lightweight (less than 50% of AGM), charge faster than AGM and you can use almost their full capacity. The lifespan of LiFePo4 batteries is significantly higher than AGM batteries (5 times higher or more). Should you opt for Lithium Ion, make sure to choose a high quality product that comes with a battery management system (BMS). This will make sure, batteries operate in a safe state.

  • lightweight
  • fast charging
  • longer lifespan
  • almost full capacity can be used
  • high price
  • special charger is needed

What’s the right battery type for you?

Consider AGM if the following applies to you:

  • You mostly use your van for short trips or over the weekends
  • You usually hook up your van to shore power anyways (e.g.: campgrounds)
  • Weight is not an issue in your van conversion
  • You are on a tight budget for your campervan electrics or the whole build

LiFePo4 can be the right choice for you, if:

  • You’re planning longer trips or live self-sufficiently in your van full time
  • You need to stick to a weight limit with your build
  • You use equipment that needs a lot of power and/or plan on cooking with electricity
  • You want the batteries to last over many years without replacing them

In our setup we connected 3 x 100 Ah of LiFePo4 in parallel. You can buy the same battery here.

What’s the right size of your battery?

You can now choose your ideal battery capacity based on the energy consumption, that you calculated earlier in this blog. Based on that value you can make use of our “rule of thumb” to find the right battery capacity:

AGM capacity
LiFePo capacity

Using this rule your battery will carry you over a full day without recharging or damaging the battery. Depending on the charging options you choose later on, this factor may change. We see this as a good starting point and our systems works great with this dimension.

Note:

Most RVs campervan electrics come with a battery capacity of less than 100 Ah as manufacturers assume, you’re only using interior lights and charge your phone or laptop. If you’re planning on living in a van fulltime, 100 Ah might not be enough for you however. We would recommend to go a bit higher, depending on your individual needs. Also keep in mind that batteries loose capacity over time and charge cycles. It’s a good idea to start out with a slightly higher capacity to compensate. Our rule of thumb caters for that already.

RECHARGE BATTERIES

Battery to battery (B2B) charger

A B2B charger allows you to charge your batteries over the van´s engine. Those chargers are often referred to as “DC-DC chargers” or “charge boosters”. This will be your back-up if you don’t get enough power from solar on a rainy day, or if you don’t get a chance to connect to shore power. With this setup you can always recharge your batteries whilst driving.

There are a couple of things to consider when choosing a B2B charger:

  1. It has to be compatible with the type of battery you’re using (e.g. Lithium-Ion)
  2. Pay attention to the maximum current it may take from your car´s starter battery. This value should not exceed 25% of the maximum Ampere of your car´s alternator in idle.
  3. It should switch off automatically before discharging the starter battery. Otherwise your van may need a jump-start ☹

Example:

  • Ram Promaster 2500 with 160 A alternator -> B2B with 40 A average current input
  • Fiat Ducato 2.3 Multijet with 140 A alternator -> B2B with 35 A avergae current input

Shore power

Another very common option in campervan electrics is a connection to shore power. This means you have a socket or a device in the van enabling you to connect to an external 230/120 V source to power your van. You can buy a standalone battery charger that converts alternating current (AC) to direct current (DC).

Quite often those chargers are integrated into combined devices like this solution from Victron or the inverter from Ective. Those devices often allow charging the battery and bypassing the shore power to your internal 230/120 V system at the same time. This saves you charging cycles and therefore, extend the lifetime of your batteries.

Solar power

Solar power is the new standard in vanlife. It‘s an extensive topic and this blogpost will merely cover the basics. A more in depth discussion is going to follow in a dedicated post.

To charge your batteries with solar power, you’ll need 2 things: Solar panel and solar charger.

There are two types of panels:

Solar panel types

The Monocrystalline panels usually come in a blackish color. They are higher in efficiency, but also come with a higher pricetag. The Polycrystalline panels, which usually have a blue color, are the less expensive yet the less efficient choice.

Whatever option you decide on, we‘d recommend looking at the warranty of the panels before buying. Even though you might opt for cheaper panels, you don´t want to end up re-investing and re-installing a solar panel after two years.

The main things to consider for a decision are the:

  • Area of your roof, you want to install the panels to
  • Power of the solar panel in Wp (Watts peak)

Our rule of thumb for right-sizing your solar panels for self-sufficient operation is:

solar AGM

Example: our campervan electrics is realized with 300 Ah LiFePo4 and 430 Wp solar power (almost a factor of 1.5 😉).

If you prefer to use the roof of your van for other purposes, like a roof deck or a roof rack for for additional storage, a nice solution to still use solar power is to go for foldable panels.

Those panels can be set up outside your van and stowed away while travelling. Another advantage is being able to move your panels to the direction of the sun to ensure highest output.

You can get a foldable solar panel including solar charger here.

Solar charger:

As already mentioned, you also need a special charger for your solar panels. This will get the power you collected with your panels right into your battery. If you connect the panels to the battery directly you will damage both your solar panels and battery. Don´t try this!

We recommend investing in an MMPT charger like this from Victron or the solution we use from Ective. These types of chargers enable you to get the maximum output from your panels. We installed two solar panels each connecting to an individual MPPT charger in our van. It makes our setup fully redundant and keeps us independent from shore power. In case of a damaged panel or charger we still have one fully functional system left to charge our batteries with.

AC INVERTER (230 or 120 V)

If you decide to power your 230/120 V consumers from your battery, you have to install an inverter like this. An inverter transforms 12 or 24 V direct current (DC) to 230/120V alternating current (AC). To determine the power you need your inverter to deliver, go back into the table of your consumers. Find the AC-consumer (230 or 120 V) with the highest power in Watts. Also think about the chances, you may want to use several consumers at the same time (e.g. cooking and charging your laptop?). Again, the motto should be “right-sizing”. If you can avoid using multiple AC-consumers at the same time you can choose a less powerful inverter and save money and weight.

Example:

We use an induction cooktop with a pretty high power consumption and power a full office with our campervan electrics. Therefore, we chose a 3000 W inverter which allows peaks of up to 5000 W.

Depending on your very own setup, you might also get along well with much smaller inverters of around 150 or maybe 500 W. However, we suggest to invest in a pure sine wave inverter, as many electronic devices (e.g.: coffeemaker, laptop chargers) require this to function properly.

Our Inverter is a combination of a battery charger and an inverter. Newer versions even integrate the MPPT solar charger into a single unit like this one.

CABLES & CONNECTIONS

When it comes to wiring your campervan electrics, always use stranded conductor cables.

cable types

They are also used in the automotive industry and are less likely to fail due to vibrations or other physical stress. Make sure to buy cables that are certified for this purpose by using the keywords „H07V-K“ „car wire“ „automotive wire“ or „battery cable“ when searching for them online.

The most important part of wiring is choosing the correct cable dimension especially for the AC wiring. The thickness (or cross-section diameter) of your cable is calculated from the current, voltage and the cable length. To determine the cable length measure the distance inside your van from your battery compartment to each device or outlet using a measuring tape. Just to be safe, allow a little bit more than you measured 😉

You can easily calculate your required cable diameter using this online tool.

Make sure to insert the correct cable length into the tool and set the voltage drop to 3%. You should by now know your current for each device from your table of consumers.

Now it‘s time to run the calculation for all of the wires in your van. If in doubt, or if the exact diameter that’s been calculated isn’t available, choose a slightly larger diameter according to these common cable diameters:

Now that you’ve bought a ton of different cables, how do you connect them? We strongly encourage you to avoid soldering whenever possible, because you lose all the advantages of the stranded conductor in that part of the cable and it is more likely to break. Instead, use a crimp tool and cable lugs to connect cables.

If you need to insert cables into a terminal or port of an electrical device, add a wire-end ferrule for best conductivity and crimp it with a tongue.

In order to merge or divert cables, use terminal blocks, always in combination with cable lugs. This type for larger cables of up to 50 mm2 and this for smaller cables.

terminal

Note:

Avoid using the van chassis as a negative wire. Each consumer of xour campervan electrics receives a positive (red) and a negative (black) cable. Still, the negative of your electrical system has to be connected to the car’s chassis – we recommend to do that close to the battery.

FUSES, CIRCUIT BREAKERS & SWITCHES

Every wire connection that’s longer than 20 cm should be secured with a fuse. A fuse blows before a cable or switch may overheat and catch fire. Always put your fuse close to the source of electricity (e.g. your battery or a distribution terminal) and place it on the positive wire. The rating of the fuse in Ampere is the same that you used to calculate the diameter of your cable earlier.

fuse placement

For different currents, the fuses often come in different designs:

fuses

We prefer to use car fuses for circuits up to a maximum of 25 A in our campervan electrics. For larger cable diamaters and currents up to 40 A we recommend using inline fuses or switch over to ANL directly for up to 500 A. In any case always check the fuse holders ratings!

Here you find a set of car fuses and a fuse holder/circuit breaker board with 12 slots for your 12/24 V system. This is the holder for inline fuses that we use. ANL fuses can be found easily with differen ratings.

For the230/120V system you also have to install an ELCB (earth leakage circuit breaker) for both conducting wires to safeguard against a potentially fatal electric shock.

ELCB

Place switches and battery isolators where it makes sense for your setup. You should at least install one isolator after your battery to allow maintenance and to disconnect all consumers from the power source quickly. Make sure, your switches and isolators withstand the current in the respective cables (at least the same rating as the fuse in that wire).

isolator

We hope our beginners guide to campervan electrics makes it easier for you to enter the world of electrics in vanlife. With this basic knowledge and some of our simple guidelines and rules you are ready to dig deeper.

Disclaimer:

We made every effort to make sure all information displayed on this website is correct and valid, even though simplified to make access to the basics easier for you. However, we do not warrant or accept any liability for the use of any of the information presented here. The user is cautioned to seek competent engineering assistance when carrying out any electrical installations.

Where to buy:

You can buy some of the components we recommend for your campervan electrics through our affiliate links in the text. For your convenience we decided to list the items and some more for the electrical system below. Clicking and purchasing helps us and it doesn´t affect the price:

BATTERY & CHARGERS:

LiFePo4 Battery Ective  (3 x 100 Ah) low temperature and bluetooth https://amzn.to/3dJPEkq

Inverter 2000 W including AC charger (shore power charger) from Ective https://amzn.to/36gqJRx

Inverter 2000 W combined with AC charger (shore power charger) and MPPT solar charger from Ective https://amzn.to/3yxLlkr

Inverter 1300 W combined with AC charger (shore power charger) from Victron https://amzn.to/3hkpZkL

B2B charger standalone from CTEK 10 A https://amzn.to/3ho40JL

SOLAR:

Foldable solar panel including MPPT charger https://amzn.to/3hl54xT

MPPT solar charger 15 A from Victron https://amzn.to/3qPGSqm

MPPT solar charger 25 A from Ective https://amzn.to/3hl6etf

CABLES & CONNECTIONS:

Cable diameter 0.75 mm2 https://amzn.to/3ArVXmB

Cable diameter 1.5 mm2 https://amzn.to/3dIamBb

Cable diameter 2.5 mm2 https://amzn.to/3hF4Pge

Cable diameter 4 mm2 https://amzn.to/3hgbIpd

Cable diameter 6 mm2 https://amzn.to/3dHR7aY

Cable diameter10 mm2 https://amzn.to/2V62FP0

Cable diameter 16 mm2 https://amzn.to/3hw35G0

Cable diameter 25 mm2 https://amzn.to/2UrmZK4

Cable diameter 35 mm2 https://amzn.to/2SMRABD

Cable diameter 50 mm2 https://amzn.to/3dI9A7o

230 V Cable  https://amzn.to/3e6PNyQ

Terminal block up to 300 A with 4 ports and housing https://amzn.to/3ApOPXO 

Terminal blocks small 15 A with 5 slots https://amzn.to/3hd21I3

Cable lug set of 60 for cable diameters of 6/10/16/25 https://amzn.to/3whmHTA

Isolated lugs for cable diameters 1.5-2.5 https://amzn.to/3AqeLCK

Heat-shrink tubes black https://amzn.to/2Uk8Ka4

Heat-shrink tubes red https://amzn.to/3dDxpgr

FUSES, CIRCUIT BREAKERS & SWITCHES:

230 V 230 V CB https://amzn.to/3i7ch3Y

230 V ELCB https://amzn.to/3qPa2pT

230 V distribution box https://amzn.to/36xzLcQ

Circuit breaker panel with 12 slots for car fuses https://amzn.to/3hrn2xm

Car fuses (set of 150) https://amzn.to/3dF4F78

Holder for inline fuses Audioproject A323 https://amzn.to/2Tz9TdR

ANL Fuse 300 A https://amzn.to/2Uo2w92

ANL Fuse 80A https://amzn.to/3jGMORh

Switch/Isolator with housing up to 275 A https://amzn.to/2Uo29va

MONITORS & SHUNTS (not yet discussed):

Battery monitor Simarine PICO Standard for up to 300 A https://amzn.to/3k65gD3

Simarine SCQ 25T quadro shunt for measuring current and sensors https://amzn.to/3hze8hx