Everything you need to know about installing solar panels on boats

Solar panels built specifically for use on boats are a great option as a source of backup power when you’re out on the water. Solar panels act as a way to recharge the boat's batteries and keep your appliances running, all without needing to buy gas for a noisy gas-powered generator.  

Marine solar panels are a relatively niche market, but there are plenty of options to choose from since typically, you can install any DIY off-grid solar panel on your boat. 

Our favorite solar panels for boats are:

• Topsolar flexible solar panel

• Renogy 100W 12V solar panel

• SunPower 170W solar panel

Below, we get into the best solar panels to buy for your boat depending on your needs, how to determine which size you will need, and why utilizing solar power for your boat is a smart idea.

What is the best use for boat solar panels?

Boats use a lot of energy for things like maintaining autopilot, keeping navigation lights on, and powering radio systems. Solar panels can provide the energy to carry out these tasks and maintain your boat's battery if it happens to be sitting idle. In either circumstance, your battery will never run out of energy. 

Not to mention, compared to gas-powered generators, solar panels have the added benefit of being quiet. They also don’t produce excess heat that makes sitting in your boat with a gas generator unpleasant on hot days.

You can use solar panels for any size boat. For smaller sailboats, the main job of your solar panels would be to keep the battery fully charged for your boat’s electricity. For larger boats, they help reduce or eliminate the need to use the engine to provide excess power. 

The average 30-foot boat would require about 300-350 watts of power. Depending on your energy use and boat size, you need more or less solar power to provide you with electricity.  

How to choose the right solar panels for your boat

The first step to determining what size solar panel will work for your boat is figuring out how much power your boat is using. You can do this by checking the labels on your appliances for the typical amp hours and volts used.

Or, you can use a battery monitor to measure the amount of energy your fridge, lights, or the other appliances on your boat consume while in use. After finding the amp hours your boat uses per day, you can determine the wattage of power your solar panels need to produce. 

Appliance	Power consumption	Power use (8 hours)
Mini fridge	100W per hour	800W
Lightbulb	60W per hour	480W
Fan	90W per hour	720W
	Total watts used:	2,000W

This example is extremely limited, you will need to determine how much energy your entire boat is using to make sure your panels provide enough power to keep your battery charged. But, technically if you had one 300-watt solar panel, or (3) 100W solar panels, they would generate 2,800W over those 8 hours. That energy would be more than enough to keep the above appliances running. 

The size of your boat’s battery will also factor into which size solar panel you need. For instance, many DIY solar panels are meant to act as a battery charger to a 12-volt lithium battery, which is the typical size within a boat. But if you have a larger boat with a larger battery, you might need more than 350 watts of power. 

Additional things to consider are whether you will need a charge controller and if you have enough unshaded space for your solar panels to absorb the maximum amount of sunlight. 

Do you need a charge controller? 

A charge controller acts as a regulator for the amount of energy that is transferred from your solar panel into your boat’s battery. This helps to make sure that your battery is not overloaded and overcharged, which can ruin the battery over time. 

While it is not necessary, it is a good idea to install a charge controller with your solar panel system to help manage the energy load that your battery receives. This will prolong the life of your battery while ensuring your boat uses the exact amount of energy it needs. 

Do you have enough space for boat solar panels?

Having a dedicated spot on your boat that has access to the full sun is key. Any shading, such as from a sail on your boat, will reduce the amount of energy your panels produce. While simply bringing portable solar panels aboard is an option, permanently mounting the panels to your boat makes it easier to always have your panels ready to go. 

Because boats typically only have room for a small solar system, getting the most out of your limited space is key. With limited space, it’s best to look for high efficiency panels because you will need less of them to produce the energy you need.

Learn more: What are the most efficient solar panels in 2022?

Or something as simple as the setup below can power your boat's battery and be angled towards direct sunlight throughout the day while not taking up valuable space on the boat. 

What are the best solar panels for boats to buy?

Any type of panel can be used on a boat such as monocrystalline, polycrystalline or thin-film. However, it is important to note that some companies exclude salt water and marine environments from their warranties. 

We've listed some options below, you can choose based on where you have space to put the panels. For instance, thin-film panels are less efficient but they are flexible. So if you wanted to place a few panels on your boat’s roof versus one panel taking up valuable space, thin-film panels would be a good choice. 

On the other hand, monocrystalline and polycrystalline panels have higher efficiency ratings and will ensure you get the most energy from your limited space or during low-light conditions. So if you have a location that can support racking, monocrystalline or polycrystalline solar panels are a better option. 

Below are some of our top picks for solar panels for boats:

Most practical 

Topsolar flexible solar panel 

Cost: $149.99 Buy Now

The Topsolar 100W flexible solar panel is a practical, semi-flexible, cheap option. It does not come with a charge controller or an inverter but you can buy a few of these to create a simple solar panel system on your boat.  

This flexible panel also allows you to utilize more space since this can be molded to fit untraditional angels on your boat. 

Best quality, small cost 

Renogy 100W 12V solar panel 

Cost: $103.44 Buy Now

The Renogy 100W 12V solar panel is a great option. At 21%, it is a high efficiency monocrystalline panel manufactured by a reputable solar panel company.

There are pre-drilled holes for easy drilling to a mount on your boat. If you have space to secure solar panels to a mount, the Renogy panels will help you maximize energy output.

Best overall 

SunPower 170W solar panel

Cost: $399.00 Buy Now

The SunPower 170W panel is a great flexible solar panel for off-grid use. Choose this option if you are interested in the versatility that a flexible solar panel offers and also want a reputable brand name with a high efficiency rating. 

While these panels do not come with a solar charge controller, they must be used with one, so add one to your cart like the Victron Energy SmartSolar MPPT charge controller. 

Why solar panels are a good choice for backup power on boats

Having a source of backup power on a boat is very important, you do not want to be caught far from land with a dead battery. Solar energy is the perfect choice because on a typical boating day, there is ample sunlight available as renewable energy. Because boats rely on a battery for electricity, a solar panel can ensure that this battery always has power. 

There are many solar panel options available for your boat and can easily be installed DIY. They will help with your sense of security while saving money because you can skip out on the traditional gas generator and rely on a self-sufficient solar power system.