Harnessing Solar Power for Campers and Caravans

Whether you're a seasoned traveler or just starting your adventure, this guide will equip you with the knowledge you need to embrace the solar revolution and experience the freedom of the open road like never before. Let's embark on this solar-powered adventure together!

Thanks to new technologies and the rapid development of the market, the installation of a solar system to power a camper or caravan is increasingly affordable and easy to implement.

With a solar system, we can easily add energy to our batteries without having to carry and light a noisy gasoline generator or start the motorhome engine for hours to charge from the alternator.

[caption id="attachment_2218" align="aligncenter" width="723"] Portable Solar Panel Kit[/caption]

How does the solar system work in our camper or caravan?

[caption id="attachment_2206" align="aligncenter" width="640"] Basic diagram of a solar system at 12V[/caption]

A typical solar system in a camper or caravan consists of four main components.

1. Solar panel. A device converts solar radiant energy into electrical energy.

2. Wiring. Transfers energy between devices in the system. The standard for connecting solar panels for connectors of type MC-4.

3. Solar controller. The main activity of this device is to regulate the current and voltage from the panels to the battery. Take care of the health of your battery by monitoring its indicators and changing its parameters.

4. Battery. Stores energy in the system, which can be used at a later stage.

Solar Panels

[caption id="attachment_2207" align="aligncenter" width="640"] Solar panel[/caption]

How does the solar panel work?

The solar panel converts photons from the sun into electrical energy.

Photons from the sun fall on the solar cells in the solar panel, some of which are absorbed by the semiconductor material and generate electrical energy.

[caption id="attachment_2208" align="aligncenter" width="636"] Solar cells[/caption]

What are the two main types of panels used for campers and caravans?

The two main types are Monocrystalline or Polycrystalline Solar Panel. Both types are suitable, but there are a few major differences that you should be aware of before making your choice.

What's the difference?

[caption id="attachment_2209" align="aligncenter" width="640"] Solar cells main differences[/caption]

Monocrystalline

• Monocrystalline ones, as the name suggests, are made of monocrystalline silicon (mono-Si), also called single-crystalline silicon.
• They have a better performance and therefore a smaller size than polycrystalline ones at the same power. If you have limited space on the roof, this is important.
• They are usually black in color.
• More expensive

Polycrystalline

• They are made of many pieces of raw silicon, which melts and spills into regular shapes.
• Larger sizes.
• They can be easily recognized by the color blue.
• Easier to make and cheaper than monocrystalline ones.

Wiring and protection

How do I connect the panels?

Basically, there are two ways to connect more than one panel. Serial or parallel.

Serial (or sequential connection)

[caption id="attachment_2210" align="aligncenter" width="640"] Solar panels connected in series[/caption]

When connecting panels in series (in series) you increase the voltage in the system, and the current remains the same. And all the panels work as one. The serial connection is as follows – from the first panel the positive cable connects to the negative one of the second and so on. MC4 jacks are male and female, and this process is quite easy.

Advantages

• Thinner cables – easier to operate and cheaper.
• The distance between the panels and the controller is of less importance because of the high voltage.
• Fewer cables.

Parallel

[caption id="attachment_2211" align="aligncenter" width="640"] Parallel connected panels[/caption]

In parallel connection, each panel works as a stand-alone. All positive cables are connected to one wire, as well as all negative ones. Thus connected the current will rise to the sum of all separate, and the voltage will remain equal to the nominal of a separate panel.

Advantages

• Works better when one of the panels is shaded or dirty, does not affect the other panels.

Parallel or serial connect the panels?

A question that has no definite answer. Depending on your controller, budget, number of panels and preferences.

How do the panels connect?

[caption id="attachment_2212" align="aligncenter" width="640"] MC4 is the most common connector for panels[/caption]

The most common connectors for solar panels are MC4. They are waterproof and easy to operate. Any other junction boxes, soldering or quick connections are not recommended. Ready-made Y connectors are also available for two or three panels in parallel connection.

Defense

You can place circuit breakers between the panels and the solar controller, as well as between the solar controller and the battery. They must be properly sized and consistent with the maximum current at the input and output of the controller.

Solar charge controller

What does the solar controller do?

[caption id="attachment_2213" align="aligncenter" width="640"] Adjusts the input voltage[/caption]

A solar controller is a device that regulates the voltage and/or current coming from the solar panel to the battery in the system. The solar controller monitors for:

• The state of charge
• Battery type
• At what stage is the charging
• Temperature

Why do I need it?

[caption id="attachment_2214" align="aligncenter" width="640"] Why do you need a solar controller?[/caption]

If you simply connect a solar panel to a battery, you can create serious headaches. Batteries have charging and discharging parameters – current, voltage. If they are exceeded when charging or discharging, you will shorten the battery life significantly or worse, a fire can start.

What are the types of solar controllers?

[caption id="attachment_2215" align="aligncenter" width="640"] Solar Controller types[/caption]

There are two types.

• Pulse Width Modulation (P.W.M.)
• Maximum Power Point Tracking (M.P.P.T.)

[caption id="attachment_2166" align="aligncenter" width="640"] Solar Charge Controller[/caption]

What is the difference between P.W.M. and M.P.P.T. controller?

These are two different ways of working, hence the name.

Pulse Width Modulation (P.W.M.) solar controller

P.W.M. is the more elementary type. In a nutshell, they try to equalize the voltage between the panels and the battery.

• P.W.M. opens and closes the circuit of different intensity (pulsation – hence the name).
• P.W.M. controller is about 10% – 40% less efficient than M.P.P.T.
• May cause disturbances in the motorhome or caravan circuit.
• On the other hand, P.W.M. is much cheaper and a good choice in a small system (100-150W)

Maximum Power Point Tracking (M.P.P.T.) solar controller

• A much more complex device that, through a microprocessor, monitors the best charging conditions and reduces losses.
• It is used in larger installations where the voltage of the panels exceeds much above 12V. The solar controller reduces the output voltage by compensating for losses with a higher current.
• These controllers allow the use of thinner cables due to the higher voltage on the side of the solar panels.
• Up to 40% more effective than P.W.M.
• Significantly more expensive. But with many more features – remote monitoring, fine tuning, charging a starter and home battery and more.

Tips for installing and using a solar system

[caption id="attachment_2217" align="aligncenter" width="640"] Installation and use tips[/caption]

• Plan well where you will place your panels. They should not be overshadowed by other devices or elements of your roof. Leave enough space underneath for good convection – the panels heat up and their productivity drops significantly. If you freely move air under them, they will work much better for you.
• Park so that you can make the most of the sun's rays. If trees or buildings are in the way of the sun, your panels won't produce anything.
• There are countless different sizes and capacities panels on the market, plan the power you need in advance according to what autonomy you want to achieve. Don't forget to check how much real space you have in the attic of your camper or caravan.
• Do not forget to put the necessary circuit breakers – automatic and manual in the system. Thus, you will easily be able to break the chain when necessary or in case of emergency. Make all relationships healthy. If you are not confident in your knowledge or skills, you remain that of professional.
• Replace all the bulbs in your camper or caravan with an LED. Most older campers and caravans have halogen bulbs, and they are not known for energy efficiency. You can reduce energy consumption by this step alone.
• Clean your panels regularly. Due to the fact that they are installed horizontally, they often collect all sorts of dirt and usually rain can not wash them. Wash them with lukewarm water and a little soap.