Camper Wiring: In Series or Parallel?
All you need to know about camper wiring on series vs parallel
That, my friends, is the question. There comes the point in every van conversion where we must tackle these problems. They’re complex and confusing. Today, we’ll discuss the following:
First of all, we have to understand what the terms series and parallel mean.
Firstly, camper wiring in series means that components are connected end-to-end, providing only one path for the current to flow. For example, imagine water flowing through a pipe. In a series circuit, the water flows from the main pipe and through your boiler to the kitchen tap.
A parallel circuit is the opposite. There is more than one path for the current to flow. Connect electrical cables to branches in the circuit to create a parallel circuit. In this scenario, your water pipe splits into 2 – allowing the water to flow freely to the boiler and the kitchen tap.
In the same way, the water flow must split between the two branches, and so must the electrical current in a parallel circuit.
Next, we will examine how current and voltage differ within series and parallel circuits within camper wiring.
Regardless of whether your camper wiring circuit is series or parallel, the same total energy and power will be available from your batteries. It is important to say that how it is connected will determine the voltage and current at various points in the system.
Similarly in water pipes, the current in a series circuit will be the same at all points in the circuit. In parallel, however, the current will be equal to the sum of the current through each branch.
On the other hand, voltage is the opposite. In parallel, the voltage is the same across all branches of the circuit whereas in series, the total voltage is the sum of the voltage across each component.
It may seem like we’re getting into the nitty gritty of camper wiring here, but this is the important part when it comes to deciding how your batteries (and solar panels – but more on that later) will be wired.
Let’s assume for now that you’re using two 100Ah, 12V batteries. If they’re wired in series, your circuit will be 24V, but the maximum current you can draw will be 100Ah. If wired in parallel, your circuit will be 12V, but you’ll be able to draw a higher maximum amp hours – 200Ah.
When buying your appliances inside your van (like your USB chargers, lights, heater, etc.), they’ll be specific to one voltage. This means that lights designed to work on a 12V system will not work if you wire your multiple 12V batteries in series. This is why we can’t use household electrical products in your campervan. They have been designed to be used with 230V.
So the real issue behind how your batteries are wired is what voltage you want your system to be.
The act of choosing if you want your campervan leisure batteries wired in series or parallel comes down to the size of your campervan electrical system. Most systems will be fine with a 12v system, therefore wiring in parallel is best. However, some very large systems will want a 24V system which requires the leisure batteries to be wired in series.
For most van owners, you will want a 12V system powering your appliances. Most roof fans, van lights and USB chargers are available for a 12V circuit, which will dictate connecting your batteries in parallel.
As a rule of thumb, any appliances that pull less than 3000W can run off a 12V system without significant difficulties. However, if you plan on running any appliances that draw more than 3000W, you may want to consider a 24V system.
Trying to run an induction hob or similar power-hungry appliance using a 12V system will need you to install cables with a much larger conductor.
Larger cables are used to supporting larger current draws and are more expensive and more awkward to install (since they can’t bend as easily and may not fit through small spaces in your van). This is why larger systems with large power draws may favour wiring your batteries in parallel to increase the voltage. Also, it could let you half the size of your cables!
In general, camper wiring of 12V batteries in parallel offers the optimal solution for most van converters. 12V appliances are relatively easy to come by, and conductor sizes won’t be too onerous for most applications.
However, a few niche conversions may require wiring in series to achieve 24V or even higher.
For example:
When converting a double-decker bus or something larger than your average van, your starter battery might already be 24V. Therefore, it would make sense to keep the rest of your system at 24V.
If you think this applies to you, we’d recommend getting in touch with our team before you make any concrete decisions or start placing orders. We fully appreciate that there’s a lot to be considered here. Our expert team can help you dive deeper into this subject.
To wire your batteries in parallel, you will need to connect the positive terminal of one battery to the positive terminal of all other batteries in your array and vice versa for the negative terminals. This is shown for a simple 2- and 3- battery collection in the diagrams below.
This is pretty straightforward to do, but it’s worth ensuring that the connections to the positive and negative busbars are made from the opposite ends of the battery array and that the cables between your battery array and busbars are the same lengths. This will ensure your batteries are loaded equally instead of constantly draining one before the others.
Camper wiring in series is rarely the way to go, but if you believe this is the approach that’s best for what you are looking to get from your van conversion, then please get in touch with one of our team, and we’ll be happy to help design a system that meets your needs.
Additionally, you will have to consider balancing your total battery capacity and required system voltage with the battery technology and how many batteries will make up your array. Wiring in series is generally done with 12V batteries to produce a 24V or 48V collection (using 2 or 4 batteries, respectively).
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