Solar Power For Boats: A Guide To Installation

Solar panels are a great way to harness the sun's energy and provide a renewable energy source for your boat. They are lightweight, require little to no maintenance, and can be installed in a variety of ways to suit your boat's unique needs. In this guide, we will cover everything you need to know about installing solar panels on your boat, from the benefits and types of solar panels to the installation process and beyond. So, whether you're an experienced sailor or just starting out, read on to learn how to put solar on your boat!

Solar panel types and their advantages/disadvantages

Solar panels are a great way to generate clean and renewable energy for your boat. They can reduce your dependence on shore power, extend your cruising range, and save you money on fuel and maintenance costs. There are three main types of solar panels: monocrystalline, polycrystalline, and thin-film. Each type has its own advantages and disadvantages.

Monocrystalline Solar Panels

Monocrystalline solar panels are made from single-crystal silicon cells, which have a high efficiency (typically 15-20%) and a long lifespan (25-30 years). They are also more resistant to high temperatures and shading than other types of panels. However, they tend to be more expensive and heavier. Monocrystalline panels have a uniform black, blue, or gray appearance and are generally quite rugged. They are constructed of thin slices of crystal silicon housed in a rigid, aluminum frame and covered with tempered shatterproof glass.

Polycrystalline Solar Panels

Polycrystalline solar panels are made from multiple-crystal silicon cells, which have a lower efficiency (typically 10-15%) and a shorter lifespan (20-25 years) than monocrystalline panels. They are also more prone to high temperatures and shading. However, they are usually cheaper and lighter, making them a more economical option. Polycrystalline cells are sliced from a cast silicon block and have a shattered glass appearance. They are built in a similar way to monocrystalline panels but have a rectangular shape, giving the panel a tiled look.

Thin-Film Solar Panels

Thin-film solar panels are made from thin layers of materials such as amorphous silicon or copper indium gallium selenide (CIGS). They have low efficiency (around 5-10%) and a very short lifespan (10-15 years). They are also very sensitive to high temperatures and shading. However, thin-film panels are flexible and lightweight, making them suitable for mounting on curved surfaces or integrating into fabrics. They are the least expensive option among the three types but may require more panels to achieve the same output as monocrystalline or polycrystalline panels.

When choosing a solar panel type for your boat, consider factors such as power needs, budget, available space, and mounting options. Monocrystalline panels are ideal for those seeking high efficiency and long-term durability, while polycrystalline panels offer a more economical option with slightly lower performance. Thin-film panels provide flexibility and lightweight advantages but may require additional panels to meet power requirements.

How to calculate how many panels you need

The number of solar panels you need for your boat depends on several factors, including your electricity usage, available space, and the size of your boat battery bank. Here's a step-by-step guide to help you calculate the number of panels required:

Determine Your Electricity Usage:

Calculate your daily power consumption by listing all the electrical devices you plan to use, along with their wattage and estimated usage time. This will give you an idea of how much power you need to generate from the solar panels.

Assess Available Space:

Consider the available space on your boat for mounting the solar panels. Measure the area to determine how many and what size panels can fit. Flexible panels can be bent or curved to fit certain areas, while rigid panels require flat surfaces.

Consider Your Boat's Battery Bank:

The size of your boat's battery bank plays a crucial role in determining the number of solar panels needed. As a general rule, a 100Ah deep cycle battery requires 180 watts of solar power to fully charge, assuming sufficient sunlight. So, if you have a larger battery bank, you'll need more solar panels to meet your energy requirements.

Calculate Required Solar Wattage:

Multiply the total wattage of your electrical devices by the number of hours you plan to use them daily. Then, consider the average sun-hours per day for your boat's location. You can find this information on websites like Big Frog Mountain. Finally, use the formula: (Total Panel Watts) x (sun-hours/day) = Watts of power/day. This calculation will give you an estimate of the total solar wattage needed to meet your energy requirements.

Choose the Right Type of Solar Panels:

Select the type of solar panels that best suit your boat and usage patterns. Monocrystalline panels are highly efficient but more expensive, while polycrystalline panels are more affordable and shade-tolerant. Thin-film panels are flexible and lightweight but less efficient. Consider the pros and cons of each type before making a decision.

Mounting Options:

Decide on the mounting locations for your solar panels. Common options include deck mounts, cabin top mounts, rail mounts (stanchion, davit, arch), and bimini or dodger mounts. Consider the available space, shading, and ease of installation when choosing mounting locations.

Calculate Number of Panels:

Based on the wattage of the panels you've selected and the total wattage required, calculate how many panels you need. For example, if you require 360 watts of solar power and choose 200-watt panels, you would need two panels.

Consider Expansion:

Finally, consider your future energy needs and allow for expansion. It's generally recommended to have a buffer in your solar panel setup to accommodate additional energy requirements or less sunny days.

Mounting options for solar panels

There are several mounting options for solar panels on boats, and the best choice depends on the type of boat and solar panel, as well as the intended use. Here are some of the most common mounting options:

• Top of pole mount: This installation method can be a clean and out-of-the-way option that allows for less shading on the panel. The pole can also serve as a dual-purpose mount for an outboard dinghy motor and electronics. Additionally, the pole can be adjustable to angle and rotate the panel towards the sun for optimal energy capture.
• Arch/Davit mount: This is a popular option if the boat already has an existing framework, such as an arch or davit. While most installations are fixed-position, it is possible to create an adjustable system.
• Bimini mount: This method is suitable for both rigid and semi-flexible panels. For rigid panels, the existing framework can be utilised, while semi-flexible panels offer more mounting options like sewing, bungees, bolting, velcro, or magnets. However, shading from the boom and rigging, as well as potential damage from the boom and sails, are considerations.
• Deck mount: This option is suitable for boats with pilothouses or hardtops, as well as decks that are not frequently traversed. For curved decks, semi-flexible panels can provide a low-profile and aesthetically pleasing installation. However, panels mounted on decks cannot be adjusted to track the sun, and shading can be a significant issue.
• Side mount: When there is limited overhead space, mounting solar panels along the side of the boat becomes an option. These panels are usually hinged so they can be folded out of the way when docking. Side-mounted panels may encounter more shading, resulting in lower average sun-hours per day.
• Removable panels: For boats that only require additional solar energy at certain times, removable semi-flexible panels offer flexibility. These panels can be quickly installed using grommets or strong magnets and can even be taken on camping or RVing trips.

What you need to install solar panels

Solar panels are a great way to harness energy from the sun and provide a renewable energy source for your boat. Before installing solar panels, it's important to understand the benefits, types of panels available, and the installation process. Here's what you need to know about installing solar panels on your boat:

Benefits of Solar Panels on a Boat:

Solar panels offer a renewable energy source, providing electricity without the need for fossil fuels or a heavy generator. They are lightweight, maintenance-free, and can be walked on, making them an ideal choice for boats. With ample sun exposure on the water, solar panels are a perfect fit for boats.

Types of Solar Panels:

There are three main types of solar panels to choose from:

• Monocrystalline panels: These are the most popular and efficient type, with the longest service life. They have a uniform appearance and are constructed from thin slices of crystal silicon, housed in a rigid aluminium frame.
• Polycrystalline panels: These panels are similar to monocrystalline but are made from cast silicon blocks, giving them a shattered glass appearance. They are less expensive but slightly less efficient.
• Amorphous or thin-film panels: These panels are flexible and lightweight, making them easy to mount on decks, biminis, or dodgers. They are also better at handling shade, as they have bypass diodes that turn off shaded cells. However, they have lower efficiency and output.

Number of Solar Panels:

The number of solar panels you need depends on your available space, electricity needs, and the size of your boat battery bank. First, determine how many watts of solar panels can fit on your boat. Then, consider your essential electricity needs and the size of your battery bank. A good rule of thumb is that a 100Ah deep cycle battery requires 180 watts of solar to fully charge with at least four hours of sunlight per day.

Mounting Solar Panels:

Mounting options vary depending on the type of boat you have. Common mounting locations include the deck, cabin top, rail mounts (stanchion, davit, or arch mount), and bimini or dodger. Creative solutions may be needed to ensure maximum sun exposure while not interfering with the operation of the vessel.

Installation Process:

To install solar panels on your boat, you will need the following:

• Solar panels
• 2-conductor wire rated for marine use, sized for a 3-5% voltage drop
• Deck plug rated for maximum amperage
• Charge controller
• Circuit breaker sized for your electricity usage
• Solar panel mounting kit

The installation process will depend on the type of mount and solar panel you choose. For deck or hard surface mounting, you will use parallel rails made from fiberglass, attached to the deck with screws. The panels are then attached to the rails with screws or pivoting clips. For flexible panels, you may use magnets or sew them into the canvas.

DIY or Hire a Professional:

While solar panel installation on a boat can be a DIY project, it is important to consider your comfort level with drilling and wiring. If you are unsure, it is best to hire a professional to ensure a proper installation and avoid potential issues due to inexperience.

Whether to DIY or hire a professional

Firstly, assess your level of comfort and expertise. If you feel confident in your ability to drill into your boat's deck and handle wiring, a DIY approach may be feasible. On the other hand, if you have any doubts or concerns about your skills in these areas, it is advisable to seek professional assistance. Incorrect wiring or drilling mistakes can be costly and may even void warranties.

Another factor to consider is time and convenience. Installing solar panels can be a time-consuming process, especially if you're tackling it alone. Professionals, on the other hand, have the advantage of experience and a team, which can significantly speed up the installation process. If you value your time and prefer a hassle-free experience, hiring a professional is the way to go.

Additionally, it's important to contemplate the potential risks and consequences. While solar panel installation may seem straightforward, there are inherent risks involved, such as working at height or dealing with electrical components. If you're uncomfortable with these risks or feel that you lack the necessary safety equipment and knowledge, hiring a professional is the safer option. They will have the training and equipment to mitigate these risks effectively.

Cost is also a significant consideration. DIY solar panel installation can be more affordable, especially if you're comfortable sourcing materials and have some technical expertise. However, if you're unsure about the process, there may be hidden costs associated with mistakes or the need for additional tools and equipment. Professionals, on the other hand, will provide a quote upfront, helping you budget more accurately.

Lastly, think about the long-term maintenance and aftercare. Solar panels typically require minimal maintenance, but it's essential to consider what you'll do if issues arise. Professionals often provide warranties and aftercare services, giving you peace of mind and someone to turn to if problems occur. With a DIY installation, you may need to troubleshoot and fix issues yourself or seek separate professional help later on.

In conclusion, the decision to DIY or hire a professional depends on various factors, including your skill level, time availability, risk tolerance, budget, and desire for long-term support. Carefully weigh these considerations before making an informed decision that aligns with your specific circumstances and priorities.

Frequently asked questions