Campervans offer the freedom to explore the open road, but their energy requirements can pose challenges when traveling off-grid. However, the use of solar panels has changed the way you can power your tiny build. By harnessing the energy from the sun, solar panels provide a sustainable and cost-effective solution. In this guide, we will explore the different types of solar panels available for campervans, their benefits and limitations, and the role of MPPT controllers in enhancing solar power yield.
Do I need solar panels on my campervan?
Whether or not you need a solar panel for your campervan depends on your specific needs and preferences. Solar panels can be a valuable addition to a campervan, as they provide a renewable source of energy that can help power various appliances and devices while you’re on the road or camping off-grid.
Here are some factors to consider when deciding if a solar panel is necessary for your campervan:
Power requirements: Assess the energy demands of your campervan. Consider the appliances and devices you plan to use regularly, such as lights, refrigerators, fans, chargers, and other electronics. If you rely heavily on electricity and plan to spend extended periods off-grid, a solar array can help meet your power needs.
Off-grid camping: If you enjoy camping in remote locations without access to electrical hookups, a solar panel can provide you with an independent power source. It allows you to recharge your batteries and power your devices without relying on traditional power outlets or generators.
Battery management: Solar panels can help maintain the charge of your campervan’s batteries. When properly connected to a charge controller, solar panels can replenish the battery bank during the day, ensuring you have power even during cloudy or rainy periods.
Budget and investment: Solar panels require an upfront investment, including the cost of the panels, charge controller, wiring, design and installation. Consider your budget and weigh the long-term benefits against the initial cost.
Space and weight constraints: Depending on the size of your campervan and the available roof space, you might need to evaluate the physical feasibility of installing solar panels. Additionally, consider the added weight of the panels and how it may affect your campervan’s overall weight capacity.
How Do Solar Panels Produce Electrical Current?
The Basics of Solar Panels
Solar panels, also known as photovoltaic (PV) panels, are composed of interconnected solar cells. These cells are primarily made of silicon, a semiconductor material that possesses unique electrical properties. When sunlight strikes these cells, a chain of events occur, leading to the generation of electrical energy.
The Photovoltaic Effect
The fundamental principle behind solar panels is the photovoltaic effect. When photons, which are particles of light, interact with the silicon atoms in the solar cell, they transfer energy to the electrons within the material. This energy enables electrons to break free from their atoms, resulting in the creation of electron-hole pairs.
The Functioning of Solar Cells
Within a solar cell, there are multiple layers that work synergistically to maximise energy conversion. The most critical layer is the p-n junction, where two types of silicon are brought together. N-type, which has extra electrons, and p-type, which has extra holes. This junction creates an electric field that drives the movement of free electrons.
Absorption and Excitation
When sunlight reaches the solar cell, it consists of tiny packets of energy called photons. The photons carry different amounts of energy depending on their wavelength. The solar cell’s material is engineered to absorb photons with energies matching the band gap energy of silicon. The absorbed photons excite electrons from the valence band to the conduction band, allowing them to move freely within the material.pro
The electrons set in motion by the absorbed photons are guided by the electric field at the p-n junction. As a result, they move toward the front surface of the solar cell, creating a flow of electrons known as a current. This current is the basis for the generation of electrical power.
Monocrystalline Solar Panels
Monocrystalline solar panels are renowned for their efficiency and sleek design, making them a popular choice for campervan owners. These panels are made from single crystal silicon, allowing them to convert sunlight into electricity with exceptional efficiency. Their high energy conversion rates, typically ranging from 15% to 20%, make them ideal for maximising power output in limited space.
Advantages of Monocrystalline Solar Panels:
Efficiency: Monocrystalline panels have the highest efficiency rates, making them suitable for campervans with limited roof space.
Space-saving: They require less surface area to generate the same amount of power compared to other panel types.
Durability: Monocrystalline panels are known for their durability and longevity, ensuring a reliable power source for your campervan for years to come.
Limitations of Monocrystalline Solar Panels:
Higher Cost: These panels tend to be more expensive compared to other options, making them a long-term investment.
Temperature Sensitivity: Monocrystalline panels are sensitive to high temperatures, which can slightly reduce their efficiency if installed in a way that has limited heat dissipation.
Polycrystalline Solar Panels
Polycrystalline solar panels are another popular option for campervan owners. These panels are made from multiple silicon crystals, giving them a characteristic blue hue. While slightly less efficient than monocrystalline panels, polycrystalline panels offer their own set of advantages.
Advantages of Polycrystalline Solar Panels:
Cost-effectiveness: Polycrystalline panels are generally more affordable compared to monocrystalline panels, making them a budget-friendly option for campervan enthusiasts.
Eco-friendly Manufacturing: The production process of polycrystalline panels generates less waste compared to monocrystalline panels.
Limitations of Polycrystalline Solar Panels:
Lower Efficiency: Polycrystalline panels have slightly lower efficiency rates, typically ranging from 13% to 16%.
Space Requirement: Due to their lower efficiency, polycrystalline panels may require a larger surface area to achieve the desired power output.
Rigid Frame Solar Panels
Rigid frame solar panels are the traditional, most widely used type of solar panel. They are characterised by their solid structure and durability. These panels consist of a series of silicon cells mounted on a rigid frame made of aluminium or steel. The frame provides structural support and protects the cells from damage.
Advantages of Rigid Frame Solar Panels:
Efficiency: Rigid frame solar panels are known for their high efficiency in converting sunlight into electricity. The rigid structure ensures that the cells are aligned optimally to capture maximum sunlight.
Durability: The sturdy frame of rigid panels makes them highly resistant to weather conditions, including strong winds. They are designed to withstand harsh environments and have a long lifespan.
Versatility: Rigid frame panels can be easily mounted on various surfaces, such as the rooftop of your campervan. They are compatible with different types of solar mounting systems, making them a versatile choice for installations.
Semi-Flexible Solar Panels
Semi-flexible solar panels, also known as flexible or bendable solar panels, offer a more adaptable alternative to rigid panels. These panels are made using thin-film solar cells, which are lightweight and flexible. They are typically mounted on a polymer backing material, allowing for some degree of flexibility.
Advantages of Semi-Flexible Solar Panels:
Lightweight and Thin: Semi-flexible panels are much lighter and thinner than rigid panels. This characteristic makes them ideal for applications where weight and space are limited, such as on boats, camper vans, or curved surfaces.
Easy Installation: The flexibility of these panels simplifies the installation process. They can be mounted on curved surfaces or uneven terrain, expanding their potential applications.
Impact Resistance: The polymer backing material provides some level of impact resistance, reducing the risk of damage caused by accidental impacts or vibrations.
Solar Charge Controllers
Multi Power Point Tracking (MPPT) controllers offer several advantages:
MPPT controllers maximise the power output from the solar panels by converting the excess voltage into usable charging current. This ensures that your batteries receive the maximum amount of energy, even in suboptimal conditions, such as partially shaded panels or varying sunlight intensity.
MPPT controllers have built-in features that prevent overcharging, which can damage the battery bank. They also provide temperature compensation, ensuring that the batteries operate optimally in different weather conditions.
Monitoring and Control
Many MPPT controllers offer advanced monitoring capabilities, allowing you to monitor your solar system’s performance and adjust settings as needed. This ensures you have real-time visibility into energy production and consumption.
Read our guide on Solar Charge Controllers
Mounting Solar Panels
To maximise solar energy production and ensure durability, proper installation and mounting of solar panels are crucial.
1 – Determine Placement: Identify the ideal location for mounting the solar panels on your campervan’s roof. Choose an area that receives ample sunlight, is structurally strong, and does not interfere with any vents, sports equipment, racks or other rooftop fixtures.
2 – Calculate Panel Size: Determine the number and size of solar panels based on your energy requirements. Consider factors such as available roof space, power consumption, and the desired amount of energy autonomy.
Need help sizing your panels?
Our system design service can assist you.
3 – Prepare the Roof: Clean the roof surface and ensure it is free from debris or any substances that could interfere with the adhesive or mounting brackets.
4 – Choose Mounting Method: There are several mounting options available, including adhesive mounts, bolt-on brackets, or fixed tilts. Select a method that suits your campervan’s roof structure and your personal preferences.
5 – Secure the Mounting Brackets: Attach the mounting brackets to the solar panels. Ensure they are positioned correctly to align with the chosen mounting method.
6 – Install Wiring and Connectors: Connect the solar panels using appropriate wiring, taking care to route and protect the cables properly.
Series & Parallel
These two methods of connecting solar panels can impact the overall performance and efficiency of your solar power system. We will delve into the pros and cons of series and parallel wiring, and discuss which configuration is better suited for cloudier days.
Series wiring involves connecting the positive terminal of one solar panel to the negative terminal of the next panel. This creates a chain like circuit where the total voltage of the system increases, while the current remains the same. The combined voltage of the panels boosts the efficiency of power transfer to the batteries.
Pros of Series Wiring:
Increased Voltage: By connecting panels in series, the total voltage of the system is increased. This is advantageous when charging batteries, as higher voltage results in more efficient charging.
Longer Wire Runs: Series wiring allows for longer wire runs between the solar panels and the batteries. This can be useful in campervans with larger roofs or when panels are placed at a distance from the battery bank.
Cost-effective: Series wiring requires fewer wiring components and is generally more cost-effective for larger solar panel arrays.
Cons of Series Wiring:
Decreased Amperage: While the voltage increases, the current remains the same in series wiring. Consequently, if one panel in the series is shaded or underperforming, it can significantly impact the overall power production of the system.
Lower Performance in Shade: Series-wired solar panels are more susceptible to power loss when partially shaded. If one panel is shaded, it can affect the output of the entire series circuit.
Each solar panel has a positive and a negative. A series connection is created when one panel’s positive is connected to the negative of another as shown in the diagram below:
Parallel wiring involves connecting the positive terminals of multiple solar panels together and connecting the negative terminals likewise. In this configuration, the current is increased, while the voltage remains the same.
Pros of Parallel Wiring:
Increased Amperage: Parallel wiring allows for increased current flow, which is advantageous when dealing with shading issues or when panels have different output capacities.
Better Performance in Shade: If one panel in a parallel configuration is partially shaded, the other panels can continue to operate at their optimal levels, minimising the impact on overall power production.
Fault Tolerance: If one panel fails in a parallel configuration, the others will continue to function independently. This increases the system’s reliability.
Cons of Parallel Wiring:
Increased Wiring Complexity: Parallel wiring requires additional wiring components and can be more complex to install, especially for larger arrays.
Higher Cost: As parallel wiring involves additional wiring components, it may lead to higher installation costs, especially for systems with numerous solar panels.
Limited Voltage: Since the voltage remains the same in parallel wiring, it may be challenging to achieve higher voltage for efficient battery charging.
Each solar panel has a positive and a negative. A parallel connection is created when one panel’s positive is connected to the positive of another and the negative of one to the negative of another. As shown in the diagram below:
Need help with Parallel and Series configurations?
Our system design service can assist you.
Performance on Cloudier Days
On cloudier days, when sunlight is less abundant, series wiring may outperform parallel wiring due to its ability to generate higher voltage. With reduced sunlight, the voltage boost provided by series wiring can compensate for the lower energy production. However, it’s important to note that both configurations will still generate power on cloudy days, although at reduced levels compared to sunny conditions.
Choosing between series and parallel wiring for solar panels on campervans depends on your specific requirements and constraints. Series wiring is advantageous for maximising voltage, while parallel wiring excels in handling shading issues. When it comes to cloudier days, series wiring tends to perform better due to its ability to boost voltage.
We at Tiny Build Electrics can determine the most suitable configuration based on your campervan’s energy needs. Get in touch and we’ll be happy to help!