Solar panels on motorhome roof

Retrofit a solar system for caravans / solar systems for off-grid

The best solar systems for the caravan and the house.

Those who are on the move want to be self-sufficient and independent. Nevertheless, many devices in the motorhome need electricity, so it seems obvious to use the roof on the motorhome to generate it. The on-board battery can be refilled with a solar system. In addition, the energy of the sun is available free of charge. We provide answers to the questions of what is important when choosing the right solar system.

Solar system for caravans

How much do solar systems cost for mobile homes?

The solar systems for use on mobile homes are often offered as a set. This already includes the charge controller, as well as all other parts that are required for assembly. All components in the set are matched to one another so that they no longer need to be modified. If the module achieves about 100 Wp, the set costs about 300 – 600 dollars. If you have sent something by hand, you can do it yourself on the motorhome. A good solar set for caravans recommended by other customers can be found here.

What performance is sufficient for a motorhome?

The selection of the suitable solar system is based on the electricity needs of the motorhome. Before a system can be selected, not only should it be determined, but also where the travel destinations that are to be reached by the motorhome are located. In the sunny south the system can possibly be dimensioned smaller than in the less sunny north. The manufacturers specify the performance of the solar system in Watt Peak (Wp). This unit of measurement describes the electrical output of a solar system under standard conditions. On some systems, the watt hours per day (Wh / d) are given, but this unit of measurement does not correspond to any international standard. The Wp information is quite suitable for a comparison of the different offers. Depending on how big they are, solar systems deliver between 50 and almost 200 Wp.

Caravan solar panels

 

Which solar system is suitable for use on the camper?

If the travel time and the electricity requirement are known, the first thing that matters is how much space is available on the mobile home roof. The solar system should also be explicitly suitable for mobile use. Then she easily takes away the vibrations and tensions that inevitably occur when driving the motor home. If, on the other hand, the solar systems are intended for permanently installed house roofs, they are rather unsuitable for operation in a mobile home. A solar system for mobile use also has a watertight junction box and a relatively low open-circuit voltage so that the motorhome batteries can be charged well.

 

What types of solar systems are there?

There are solar systems in an aluminum frame that can be attached to the roof of the motorhome using the appropriate brackets or profiles. Depending on how much space is on the roof of the caravan, the dimensions of the solar system are selected. In addition to these rigid and permanently installed solar systems, there are also models that are glued directly onto the roof. This makes sense in cases where the overall height should remain as low as possible. There are also solar modules that use different technologies and have a corresponding level of efficiency.

 

How much energy does the sun provide?

The radiation from the sun that hits the surface of the earth is called global radiation. Depending on the location, the time of day, the position of the sun and the latitude, this value averages 110 W / m². This value is highest when the sun is shining and the solar system is aligned accordingly. If the solar system on the mobile home roof is one square meter, it can generate 130 watts of power with an efficiency of 13 percent. There are manufacturers who certify that their solar systems have a significantly higher output, this value was determined by tests on the roofs of houses. Since the influence of the weather on the performance of the solar system is significant, the performance of the different systems can only be compared under test conditions. The Wp value mentioned above can be used for this.

solar panel for caravan

 

The correct alignment of the solar system

In order for a solar system to generate electricity on the mobile home, the sun must shine on it. Ideally, the solar system is oriented to the south and attached to the camper at an angle between 20 and 50 degrees. If the panel lies flat on the roof, the performance is about a quarter lower. In addition, the camper should not only be parked shadow-free so that as much sun as possible is converted into electricity, but the solar system should be installed really shadow-free. If, for example, the shadow of the antenna falls on it, full performance cannot be achieved. If there is enough space on the roof, two modules with a power of 90 Wp can be installed instead of a large module with 180 Wp. If one module is shaded, the second continues to produce electricity. However, since the performance of the solar system also drops when it gets too hot, there should be enough air under the modules for cooling.

 

Is a solar system sufficient to make the motor home self-sufficient?

That depends primarily on how much electricity is consumed when the sun is not shining. When it gets dark in the evening, electric lights often burn in the motorhome, the TV is on or the laptop is switched on. Fridge and other units also need electricity. At this time, the solar system can no longer generate electricity. Even if the motorhome is parked in the shade, the solar system delivers significantly less energy. This is not sufficient to supply the devices that need electricity and additionally charge the battery at the same time. However, if the motorhome’s battery is sufficiently sized and the solar system is constantly supplying it with fresh electricity, the motorhome can often be parked far away from sockets for days.

Dual batteries

 

Which battery is suitable for supplying the motorhome with electricity?

In principle, any battery can be used. However, a starter battery is designed for high currents that are called up at short notice. If it is constantly charged and discharged, its capacity is reduced. A wet battery is cheap, but may only be used outdoors. If a new battery is required for the motorhome that is to be charged by the solar system, make sure that it maintains its capacity over many charging cycles. Gel batteries, absorbed glass mats batteries, solar or cycle-resistant batteries are names that you can follow.

Subsequent installation of the solar system in the camper

Some campers are already equipped with a solar system. If not, retrofitting is an easy way to generate the electricity yourself. Often the charge controller can even be connected directly to the battery without affecting the electrical system of the motor home. If the charge controller has an appropriately dimensioned load output, it is no problem to connect the entire electrical system of the motor home. A controller is installed in the controller, which ensures that the battery does not receive too little voltage. If the vehicle has a special electrical panel in which an ampere meter is installed, it records all the currents that arrive in the battery. If a solar system is to capture the light of the sun and be stored as electricity by the battery, this must also be recorded by the measuring resistor. For these cases, there are corresponding charge controllers that are matched to the integrated electrical panel.

What does the charge controller do?

If the sun shines on the solar system, electricity is generated and sent to the battery. The charge controller regulates this power and ensures that the camper’s battery is not overcharged. If the solar system is purchased as a set, the system and the charge controller are coordinated. If not, the charge controller must be dimensioned so that it can also process the power of the solar cell. If the solar system has 100 Wp power, the charge controller must be able to process at least 100 W. The charge controller may like to be too strong for the solar system: Then it is still sufficient if a second solar system is mounted on the camper.

solar power

 

How does a solar system work?

People are increasingly using solar energy to save energy costs and relieve the environment. But how does such a solar system actually work? The function of a photovoltaic system is basically the same, regardless of whether it is a small solar system on a family home or an industrial system. In principle, a grid-connected photovoltaic solar system works very simply: While light falls on the solar cells, they generate direct current from them. The individual solar cells are interconnected to form larger solar modules. The individual solar modules are in turn interconnected to form a solar generator. The generated direct current is converted to alternating current using the inverter. Thanks to the conversion, the alternating current can be fed directly into the public or privately used power grid, thereby either reducing your own electricity costs.

 

How does the individual solar cell of a photovoltaic solar system work?

Almost 95 percent of all solar cells are made from quartz sand silicon (Si). Silicon (Si) is one of the most common natural elements present in the earth’s layer. Silicon is considered inexhaustible. In order to form a silicon wafer from the quartz sand – natural origin of silicon – the quartz sand must first be cleaned and crystallized. The finished product is then sawn into slices, specifically contaminated and provided with conductor tracks. These are required to transport electricity.
If light falls on the silicon wafer, electrons are released. In order to be able to use these electrons, the top and bottom of each individual cell must be specifically contaminated with different foreign atoms. Boron (Br) and phosphorus (P) are often used here. Thanks to the targeted contamination of the cell, the electrons (negative charge carriers) on one side and the protons (positive charge carriers) collect on the other side. This creates a positive and a negative pole, which is comparable to a battery. If a consumer device is subsequently connected, the current flows.
The small cells are so functional that they can generate electricity even at low light levels, such as those that occur in bad weather or cloudy skies. However, the current intensity is always proportional to the incident light intensity. Analogously, this means:

The higher the solar radiation, the more solar electricity is produced by the photovoltaic system.

Regardless of the incidence of light or solar radiation, the voltage of the solar cell behaves. The voltage of a silicon cell is continuously at 0.6 volts. However, depending on the size of the cell, the amperage is. A common solar cell with a size of 15 x 15 centimeters generates an average of about 5.5 amps of electricity. With full light, a single cell has an output of approximately 3.4 watts.

caravan solar panel

 

Different solar cell technologies of a photovoltaic solar system

There are generally three different cell types. The crystal types include:

Monocrystalline cells
Polycrystalline cells
Amorphous cells


The monocrystalline solar cell

Monocrystalline silicon cells are made from a high-purity semiconductor material. Single-crystalline rods are pulled out of the silicon melt and then sawn into 0.25 millimeter thin slices. This special manufacturing process guarantees high efficiency. The efficiency of the monocrystalline solar cell reaches between 14 and 16 percent.

The polycrystalline solar cell

The polycrystalline cells are somewhat cheaper to manufacture. Liquid silicon is first poured into blocks to produce polycrystalline solar cells. A solidification shows a typical ice flower structure made up of a large number of individual crystals. This crystal structure is of different sizes. Defects occur at the outer borders. Due to these crystal defects, the efficiency of a polycrystalline solar cell is only 13 to 15 percent.
The monocrystalline solar cell is therefore more effective than the polycrystalline solar cell.

The amorphous solar cells / thin-film cells

Amorphous solar cells are also called thin-film cells. In production, the photoactive semiconductors are applied as a thin layer on a glass pane. Connected directly to modules, the amorphous solar cells are hermetically sealed with a second glass plate. The thickness of the layers is less than 1 µm. Due to the lower material costs, the production costs are also substantially lower.
Thin-film solar modules are an inexpensive option for using solar energy. However, the efficiency of a thin-film cell is only 6 to 8 percent. A slightly higher efficiency of the thin-film cell can be achieved, for example, with new materials. These include cadmium telluride (CdT) and copper indium diselenide (CIS). The efficiency of a thin-film cell can be increased to 8 to 10 percent.

 

Solar module of a photovoltaic system

In order to design the solar module, the individual solar cells are interconnected and packaged weatherproof. As usual, the solar modules are protected from above with a glass pane. A protective film is pulled over the solar modules from below. There are smaller spaces between the solar cells through which you can look through. The individual solar modules are offered in different sizes. From a few watts to 300 watts of power.
The modules have an average output of between 130 and 250 watts. All solar modules are manufactured according to current standards and are subject to constant control. The highest quality is guaranteed.
A solar module is one of the lightweights with a weight of 10 to 15 kilograms per square meter. The size of the solar module can vary. However, sizes up to 3 square meters are not uncommon.
Solar roof tiles are now also available on the market. These are mounted on the roof like ordinary roof tiles.

How does the module of a solar system work?

The solar modules in a photovoltaic system convert sunlight into electrical energy. The light of the sun causes an electrical voltage when it hits the solar cell. This is already removed from the surface. Several solar cells are electrically interleaved in a solar module of a photovoltaic system. The electrical voltage is added together in series. Each individual cell has about 0.6 volts.
A common module with approximately 60 cells generates a module voltage of approximately 36 volts in this way. Solar modules made of crystalline silicon (Si) are most commonly used. High-purity silicon (Si), which is obtained from quartz sand, is further processed for this.
The efficiency of a solar module is between 11 and 16 percent. For example, modules made of crystal-pure silicon (Si) are used as standard on roof systems. If thin-film modules are used, the efficiency is much lower. In the case of thin-film modules, the highest is 9 percent. Due to their extremely low cost, thin-film modules are particularly suitable for the operation of large systems in which the space consumption is completely double-tier.

solar panels solar panel installation

 

The system technology of a photovoltaic solar system

A photovoltaic system / solar system can be divided into a grid-connected system or an island system. The solar generator in grid-connected systems generates direct current with the help of sunlight. This is converted into alternating current by an inverter. Only in this way can the energy obtained be fed into the local low or medium voltage grid.

In this case, the low or medium voltage network forms the energy store. The infeed and consumption are mostly out of sync in-house.
In regions without a network connection, so-called island systems with an energy storage device in the form of a battery are used.

Of course you get everything from one source. We specialize in solar systems and have extensive experience in the field of solar. We offer solar systems and complete systems that we have tested.

 

off grid solar

Stand-alone photovoltaic system – stand-alone solar system

Off-grid systems such as the photovoltaic off-grid system or a solar off-grid system are permanently installed, self-sufficient, network-independent or mobile systems as well as apparatus and local networks for power supply that can function throughout the country without being connected to a public power grid. Such a stand-alone photovoltaic system is mainly used when a connection to a nationwide power grid is not possible. The operation of the island system is also called island operation.

Both the solar stand-alone system and the photovoltaic stand-alone system are in stand-alone operation. These only supply themselves with energy and are not comparable to the on-board network of means of transport. If an auxiliary power source is available for a power failure and the engine is at a standstill for a longer period of time, an on-board electrical system, like all other systems with a mains connection, can also operate in isolated operation. Most of Europe has a very large, dense and reliable electricity network. This means that the island systems here are mostly only technical devices with very little power consumption. In addition, the wiring of these devices is enormously complex, which leads to the use of self-supply, for example with solar modules. Applications include pasture fences, toll control bridges or simple parking ticket machines.

 

Supply of AC voltage with the help of a photovoltaic island system and a solar island system

If the power consumption is very high, so-called gasoline engines or diesel engines with coupled generators are used. These enable a country-specific mains voltage. These permanently installed diesel power plants and diesel aggregates do not work very long. The engine is overhauled after just two years. Furthermore, they have a poorer efficiency than coal-fired power plants, which comes about particularly when the capacity is very high.

A good example of this is a large event with enormous electricity requirements or a remote petrol station and a small settlement. These diesel units are even used by the fire service and the Bundeswehr. But even with stand-alone systems, a relatively constant frequency of 50 or 60 Hertz is necessary to guarantee a reasonable supply of devices designed for AC voltage. This can only be achieved with direct current sources such as solar modules, accumulators and the speed control of the generator in combination with an inverter. Areas of application include toll control bridges or simple parking ticket machines.

Regenerative energies with the help of the photovoltaic stand-alone system and the solar stand-alone system. In a stand-alone solar system, falling costs and rising system prices for fuels make it increasingly economical. The choice depends on the offer, i.e. Wave energy for the sea mark, wind generator for the sailing yacht, hydropower for some mountain huts and solar modules for the motor home. The power requirement also plays a major role, so a photovoltaic system in the MW range is significantly more expensive than a wind turbine. Accumulators can also be used to bridge low-yield phases with unfortunately only a low power requirement and for a very short time. Operation with biogas or a combination with internal combustion engines is a good alternative. This is also referred to as a hybrid system. For certain devices you need a voltage converter from 12V to 230V to connect to a solar system. A special solar battery is recommended for storing the electricity.

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Visit our shop and see all our high quality solar systems. We offer solar systems for caravans and off-grid systems, such as holiday homes.

house with off grid solar system

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