We want to have some electricity to power our tools! But what to do? We’re happy to admit that we’re not interested in electricity and electronics until now. It was harder for us to get into this (for us) complicated topic at first. Every camper builder has countless questions at the beginning of the electrical installation. How much electricity do I need? Where do I want to get electricity from? Do I need a 230V connection, or is 12V enough?
Admittedly, answering these questions for our camper conversions has brought us almost endless research and a lot of desperation. In the meantime, however, our circuit couldn’t be better, and the electrician agreed. We’re proud to have solved the “Electrical Systems in a Camper Van” puzzle and are excited to expand on the electrical system in your camper van with you. Even though it seemed different to us at first, we found out: Installing electrical equipment in a camper yourself is not rocket science and can be done even by inexperienced people. Caution and enough respect are required. You can find out what you need from your camper’s electrical system and what to consider during installation here!
Shopping list for 12V camper appliances
- A roll of cane
- Feeding wire
- Crimping tool (must be at least 2.5mm2 & 6mm2 – this one is really good!)
- Ferrules for 2.5mm2 and 6mm2 cable cross-sections
- Wire stripper
- Wago terminals 221
- Flexible cable for cars with 2.5mm2 & 6mm2 cable cross-section (black and red)
- Cable lug set for 1.5mm2 & 2.5mm2 cables
- On-off switch for cars
- Large main switch
- Battery terminals
- 12V cigarette lighter
- Car fuse set
- Fuse holder
- Neutral terminal
Preparations for the 12V electrics in the camper
There is a lot to do before the first cable is laid. Because even if the cables later disappear behind the wall paneling of the camper, they must be laid properly. Once the wall paneling is on, in the worst case, you can no longer get at the cables. It is better to lay your cables well-protected by so-called empty conduits. The empty tube not only protects the cable from sharp edges and chafing. But new cables can also be pulled later through the cable duct created in this way. If you find out later that you want to retrofit some consumers, that’s no problem. With a feed wire, you can easily lay another cable behind the panel, thus retrofitting your camper.
Choosing the cables
After removing your 12V installation, many meters of cable will run through your motorhome. Laid behind the disguise, in the worst case, you will never be able to get to it again. In most cases, laying the cables is, therefore, a step that is only carried out once over the life of the mobile home. Accordingly, one should work with foresight here. The first and most important question is: Which cable is right for my requirements? Depending on what you intend to do later, there are different “thick” cables and cross-sections. You should also note that only certain cables are approved for use in cars or mobile homes.
Which cable cross-section for the 12V electrical installation in the camper?
The more current flows through your cable, the larger the cable cross-section must be. If you choose your cable too thin, this not only leads to loss of performance but also to heat development. Absolute caution is required here, as this will cause cable fires! The expected length of the cable also plays a role. To calculate the right cable cross-section, you must first know how much electricity (in watts) your consumers have and how many meters of cable lead to it. With these values, you can measure exactly which cable cross-section is sufficient. In practice, however, it is easier to roughly estimate how much current will flow through the respective cable and then simply choose a slightly thicker cable instead of complex calculations. While a cable that is too thin can be quite dangerous, a cable that is too thick is, at most, a problem for the wallet.
You can use the following cable cross-sections as a guide:
- 5mm2 for LED lamps
- 5mm2 for all consumers up to around 50 watts (12V power sockets, refrigerator, water pump, etc.)
- 6mm2 for the main cable to the fuse holder and main switch
This is how we did it: Since we didn’t want to buy an extra 1.5mm2 cable for our LEDs, we also chose the 2.5mm2. That’s pretty exaggerated for our 1W LEDs, but it didn’t bother us. Since our LEDs were already delivered with a 2-meter cable (0.75mm2), we only had to bridge the short distance from the light switch to the fuse holder.
Laying the cables
We installed a 12V socket by the bed, which runs across the ceiling to our fuse holder. We underestimated how much cable we would lay for this project (a whole six meters!). As a result, we measured the cable cross-section a little tight at 2.5mm2. This results in a fairly strong drop in performance, which means that our devices charge much more slowly on this socket than on the same 12V socket on the table.
Normal cables from house construction may not be used in the camper. These have a rigid soul and can break due to the vibrations while driving. For your camper conversion, you should only use electric cables approved for vehicle use. In contrast to the “classic” cables, they consist of many thin copper wires, so they are flexible and relatively unbreakable.
Connecting cables in the campervan
A few work steps are required, from the preparation to the final connection of the cables. What is there to consider? And what’s the easiest way to do it?
How a cable must be prepared depends on how or where it will be terminated or connected. Depending on the application, you need a clamp to connect two cables, a cable lug, or a ferrule. But don’t worry if the terms don’t mean that much to you initially. We felt the same way. We were completely haphazard and overwhelmed. You can usually tell which variant is right when you hold the respective counterpart in your hand. What all connections have in common is their preparation.
Cut the cable to the correct length. You can use side cutters for this. Or you can buy cheap electric combination pliers, which have a cutting tool in addition to a few other functions. We had such a pair of pliers and thought they were great. It is better to cut your cable a few centimeters longer at the beginning. Often the stripping does not work immediately, and then the cable is quickly too short.
Now the cable must be stripped at the ends, i.e., the rubber insulation of the cable must be removed at the ends. Depending on which connector you need, the rubber coating has to be removed to different extents. You can find information on the packaging (e.g., with the WAGO clamps) or simply try it out. Basically, no bare cable should be visible after putting on the connector. Nevertheless, a cable must be stripped about 0.7-1.0 centimeters to ensure electronic conductivity.
3. Attach cable connector
Now it gets exciting. Depending on the intended use, you now put on your cable lug, ferrule, or the WAGO terminal. When connecting your RV battery, you need to know what voltage your RV’s electrical system is. Series vs parallel battery is also something you need to know. If the voltage is 12V, you can connect multiple 12V RV batteries in parallel; if it is 24V, you must connect two 12V batteries in series.
No soldered connections in the camper electrics
What is common practice when building a house you should urgently avoid with the electrical system in your campervan: connecting the cables by soldering! Soldered connections are rigid and can quickly break due to the vibrations of the camper while driving. Of course, this, in turn, represents a security risk that can easily be circumvented. Instead of soldered connections, you can use WAGO terminals, which are much easier to use and specially made for the vehicle’s requirements. Secondly, it is suggested that you can use a dedicated power inverter instead of a common inverter.