Solar panels for boats: What you need to know

Owning a boat can be expensive; you have to pay an upfront cost to purchase it, and you'll also have to spend money on maintenance and fuel charges. Solar panels may be the answer if you're looking for a reliable, cost-effective way to power your boat.

Solar energy systems on boats work similarly to other portable, off-grid systems. There are four important components to a marine solar panel system:

1. Solar panels

2. Charge controller

3. Inverter

4. Battery

Most marine solar panel systems require charge controllers to prevent the batteries from receiving more voltage than they can handle. Without charge controllers, you risk overcharging and damaging your battery.

Depending on your boat's electrical setup and the appliances you need to power, you may also need an inverter to convert direct current (DC) electricity into alternating current (AC) electricity. Some boat electronics use DC and don't need an inverter. However, if you use everyday household appliances on your boat (i.e., TVs, microwaves, or hairdryers), they likely run on AC electricity, and you'll need an inverter.

You can buy all of these components separately, but you can find solar panel kits that include some or all of the necessary parts. Some marine solar panel kits include the wires, cables, and mounting equipment required to get your boat's solar panel system up and running.

Below are a few products tailored to off-grid marine solar power systems.

Boat solar panel options

If your solar panel kit does not include an inverter or charge controller, you must buy those components separately. Battery storage products occasionally have built-in inverters and/or charge controllers.

There are numerous benefits to powering your boat with solar energy. One of the most attractive benefits of marine solar power systems is the monetary savings. You'll need to invest money upfront to purchase solar equipment; however, once it's up and running, you'll generate free electricity for your boat. Alternatives to electrifying your boat, like gasoline-powered generators, require purchasing fuel on an ongoing basis. Switching to solar power can reduce these purchases while protecting you against rising fuel costs.

Another benefit of marine solar panel systems is the quietness of operation. Running a generator can be a noisy disturbance for those going out on the open water to experience nature. Powering your boat with solar allows you to enjoy peace and quiet without losing power.

Furthermore, you can also safely generate electricity and charge your battery with solar power while you're away from your boat. This isn't feasible with generators - running a generator requires manual operation and monitoring. With solar panels, you can produce usable electricity during the day and then use it for weekend boating adventures.

However, there can be obstacles to installing solar on a boat, perhaps the largest of which is available space. Ideally, your solar panels can be installed in an area with uninterrupted sunshine. Depending on your boat type, this space may be easy or difficult to come by. While you likely get a lot of sun out on the water, the area may be too small or have too many obstacles that make fitting the number of solar panels necessary to generate your electricity needs difficult.

Consider your boat's deck or canvas when you're looking for spots to install a marine solar panel system. Remember that the positioning of your solar panels will also impact the type of equipment you should purchase – you may be able to use traditional monocrystalline and polycrystalline solar panels if you're installing on a fixed, rigid section of your boat. However, if your only open space available isn't suitable for fixed mounting, installing lower-efficiency flexible solar panels may be a better option. Some flexible solar options have an adhesive backing, so you won't need to worry about the constraints of traditional mounting and racking materials.

Unsurprisingly, a yacht has very different power requirements than a sailboat. The number of solar panels you'll need for your boat not only depends on the type and size of your boat, but also the quality of the equipment you choose, how many sun-hours the boat sees, and the amount of electricity you require. Some boats can get by with one 100-watt solar panel (or even smaller), while others need a multi-panel setup.

Calculating your electricity load is the first step in determining how many solar panels you need. Below are some common appliances you may use on your boat and what they draw for power.

How many solar panels do you need for common appliances?

The last column of the above table is the amount of energy you'll consume in watt-hours running each appliance for the number of hours identified in column three. One 100-watt solar panel that receives direct sunlight for 5 hours will produce approximately 500 Wh of electricity (5 hours x 100 W = 500 Wh). Not considering conversion losses, that's enough electricity to power a mini-fridge for 24 hours or power a boat's GPS display for 10 hours. Running all of the appliances above for everyday use will require multiple 100-watt solar panels or fewer higher-wattage panels.

You can save money by installing a marine solar panel system, but you'll save even more by installing solar on your home or business. If you want to evaluate your solar options, check out the EnergySage Solar Marketplace. You can receive up to seven custom solar quotes from local installers to compare. You can also try our solar calculator for a quick estimate of solar costs and savings on your property.