Solar power is quickly becoming one of the most popular forms of green energy in the world. It’s also one of the most accessible forms of green energy, with solar panels getting more affordable every year. When you pair that cost reduction with the incentives the federal government offers to homes that utilize green energy, these systems are paying for themselves faster than ever.
Investing in solar for your home can still be costly, which has led many DIYers to try and tackle the project on their own. Is it possible to build and install your own DIY solar panels? The answer is a resounding yes, but it will take some research and a bit of elbow grease. Let’s take a closer look at what it takes to build and install solar panels to get your home off the grid.
Determining Your Home’s Solar Potential
The first step before you start designing your DIY solar array is to determine the solar potential of your home. This will depend on a lot of variables, including:
- The home’s location
- The average usable solar hours
- The average number of sunny vs. cloudy days
- Weather events that could damage the arrays
- The type of roof
- Which direction your roof faces
There are several different tools to help you determine things like average weather and usable solar hours. One is Google’s Project Sunroof. It uses an aggregate of images taken over the past year to determine whether your home would be a viable candidate for solar energy based on your street address. Since Google Earth powers it, if you live in an area that Google struggles with, you can input the coordinates of your home as well.
The United States Department of Energy also maintains a list of sites that you can use to determine your home’s solar potential, although some require more expertise than others.
Calculate Your Load
Next, you’ll need to calculate the load that your solar array will take on. This is how much power you need it to generate to offset your energy costs or provide energy for your entire home. Thankfully, this can be reasonably simple even if math isn’t your forte.
Most of the online load calculators require you to enter all of your appliances and all of the potential drains on your power grid. While this will provide you with the most accurate load calculation, it can be tedious, simply because we use electricity for so many parts of our lives.
To get a general idea of the amount of energy your home is using, just take a look at your monthly electric bill. This will let you know how much energy you’re using each month on average. It may vary during different parts of the year depending on your location. Homes with electric heating will use more electricity during the colder months, while in the south you can expect to see higher bills during the hot summer months.
Once you have that number, divide it by the number of days in the month. If, for example, you’re using 1,000 kWh of power in June, you’ll divide it by 30 days to determine the amount of energy you use on average every day. In this case, it comes to roughly 33.34 kWh per day.
Finally, look at the number of usable sunlight hours that your home receives daily. Depending on where you live, that could be anywhere from 1-6.5, at least in the U.S. Divide your kWh per hour by the number of usable solar hours you receive, and you’ll know what kind of load you need to plan for.
Using our same example, if you live in Arizona and receive 6.5 usable solar hours a day, you’ll need a 5.13 kWh system to meet all your power needs.
It’s a good idea to compare your calculations for more than one month so you have a clearer picture of the power variations you’ll experience throughout the year.
[Editor’s note: If you’re wanting to use solar panels to get off grid, you’ll really want to reduce your home’s power needs as much as possible. This could include opting for energy efficient appliances to alternative sources of heat (e.g., a wood burning fireplace) and even changing how you accomplish daily tasks, such as drying laundry on a clothesline or cooking via wood stove when possible. Reducing power consumption is always a wise choice for a variety of reasons!]
Types of Solar Panels
Now that you know how much power you’re going to need to generate from your solar array, it’s time to choose the type of panel you’re going to install. There are three different types of solar panels currently available on the market if you decide to purchase pre-made panels. We’ll talk more about creating your own panels in a moment.
Monocrystalline panels are the most expensive option but offer the best efficiency and performance. If you live in an area that doesn’t get a lot of usable sunlight during the year, monocrystalline panels may help offset the lack of sunlight. Polycrystalline panels are an excellent middle-of-the-road option, offering decent efficiency and performance for a lower cost.
The difference between the two is in the solar cells. Monocrystalline panels use solar cells cut from a single silicon crystal, while polycrystalline cells use fragments of silicon which make the less efficient, but cheaper.
Finally, there are thin-film solar cells. These are relatively new and inexpensive, but offer the lowest level of efficiency and performance. They are a better choice for homes that can’t support heavy solar panels on their roofs.
Right now, modern solar panels provide between 11 and 15% efficiency, meaning they can convert up to 15% of the solar energy they collect into usable electricity. In lab settings, scientists have reached up to 40% efficiency, but that’s not currently available for the average consumer.
Designing Your Array
With your information in hand, now you can move on to designing your array. This will be one of the last planning steps before you start gathering your supplies and working on your installation.
This step depends mainly on the array size necessary to provide for your power needs, as well as the design of your roof and how you’re planning to attach the panels. If you’re not sure where to start, consider scheduling a free consultation with a professional solar installer to get their opinions on the best way to incorporate solar into your home’s power grid. Even if you’re planning to build and install the panels yourself, talking to a professional can help you put together a more comprehensive plan.
Now you have a choice to make. Do you want to build your solar panels or purchase pre-assembled ones?
Building Your Own Solar Panels
Contrary to what solar installers might have you believe, it is possible to build your solar panels from scratch. It’s a time-consuming and often tedious process and it does require some electrical skills. Once you understand the science behind it, however, solar panel technology is relatively simple.
On average, a single polycrystalline solar panel will use 60 square silicon wafers, but you can scale that number up or down as necessary. You can purchase these wafers online, allowing you to customize your panels to meet your home’s power needs better.
Start by creating a backing for your solar panel. Many people use plywood boards as their backers, but you can use pretty much anything that will survive in the elements for extended periods. Drill holes in the backer to allow the wiring of the panel to pass through.
Wire each of the solar cells together and attach them individually to the backing. The last step isn’t strictly necessary, but it does make things easier if you find yourself needing to replace a single cell if it gets damaged or burned out.
You also want to add a layer of glass or acrylic above the installed panels to protect them from the elements. This becomes especially important if you live in an area that is prone to severe weather or hailstorms.
Here’s the idea in action, if you’re interested:
Installation — Roof or Ground Installation
Now that you have your solar panels, it’s time to figure out where you’re going to install them. For most homeowners, there are two options — rooftop installation and ground installation. Rooftop solar arrays are the most common, but in some situations the roof can’t support the weight of the panels. Then, creating ground-based panels becomes the only option.
A roof inspection can help you determine whether your home is capable of supporting a solar array on the roof. If you haven’t replaced your roof recently, or your home is older, you may need to upgrade the structure or consider a ground-based array.
Ground-mounted solar panels can be more productive than rooftop systems because you aren’t stuck relying on the angle of your roof. You can install the panels at the best angle to capture the most solar energy.
Sun Tracking — Necessary or Excessive?
In parts of the country that get a lot of usable solar hours year-round, a fixed-panel system may be more than sufficient to meet your home’s energy needs. For the rest of the world, a sun tracking system can help make up the difference. These systems make your solar panels shift position, following the path of the sun throughout the day.
This can be a boon for homes in northern climates, where the position of the sun changes dramatically throughout the year. Solar trackers come in two varieties — single and dual-axis. Single-axis trackers track the sun from east to west throughout the day but only move in one direction. Dual-axis trackers move on both the X and Y-axis, allowing the system to track the sun no matter where it is in the sky.
Sun trackers, like other solar technology, have become more affordable in recent years. According to industry experts, using a sun tracking system can increase an array’s yield by 15-30% over a comparably sized fixed system.
Sun tracking might be excessive in areas that already get a lot of usable solar hours. For homes in areas that don’t, they can be a valuable tool to get your home off the grid. Be aware that installing sun trackers adds a lot of moving parts to your system, increasing the number of things that could potentially break down.
[Editor’s note: Solar tracking systems can get expensive. But this solar phase change tracking system got me excited because I recently watched this video by Engineer775 (Scott Hunt) showing a demo unit that allows your solar panels to track the sun without motors, controllers, and other items that are typically necessary. Unfortunately, it doesn’t appear to be for sale yet, but the idea is certainly something to pay attention to if you’re looking into solar tracking systems. Watch the video below.]
Connecting to Your Home’s Grid
The last major step here is to hook the solar panels to your home’s grid so they can start generating electricity. You will need a few items for this step, including a charge controller, an inverter, and a net meter if you’re planning to set up a grid-tie system. Grid-tie means you’re generating your electricity but haven’t wholly disconnected from the local power grid. This can be a boon because in many areas, if you make more electricity than you need, the utility companies will buy it from you at a premium.
There are two types of inverters on the market — ones designed for grid-tie and ones intended for completely off-grid setups. Either way, you’re going to need an inverter, because solar panels generate DC (direct current) power, and American homes use AC (alternating current) power. Make sure you’re choosing an inverter that matches the amount of energy your solar array will generate.
If you’re going for a grid-tie system, call your local utility company. In many cases, they will be happy to provide you with a net meter to determine how much extra power you’re generating. This is beneficial for them as well because it takes some of the load off the grid, especially during high-demand times.
Assessing the Need for Battery Backups
If you’re going strictly solar, the last thing you’re going to need to consider is a battery backup system. Solar power is great on sunny days, but if it’s raining or you need to charge your phone after the sun goes down, you’ll be out of luck. Battery backups store solar energy during the day and give you access to it when the panels aren’t generating.
Unless you’re using a grid-tied system or supplementing your solar array with other types of green energy, you will need a battery backup system. Some brands like Tesla market their battery walls as a necessary addition to solar power systems, but you don’t need to break the bank to set up a battery backup for your home. Determine how long you want your battery backup to support your home — with one to four days being the average — and figure out how many batteries you’ll need to keep your life moving forward.
Opt for deep-cycle batteries that can withstand multiple discharges without damage. Boat batteries are a popular option for this, though you can also choose to invest in dedicated solar batteries to create your backup.
[Editor’s note: You’re definitely going to want to do some research to get your battery bank setup correct since there’s a lot that can go into the decision, including battery type, voltage (e.g., 12-volt or 24-volt), discharge capacity, and more. It’s going to be expensive and can even be dangerous if you don’t do things right. Definitely contact someone with the correct knowledge to get this correct! Following is a good video to help you get an idea of how much battery power you may actually need beyond just looking at your utility bill.]
Get Off-Grid With Solar Power
People decide to install solar in their homes for all sorts of reasons. Whether you want to get off the grid or are just trying to reduce your utility bills, you don’t need to rely on solar installers to get the job done. All you need is some patience, some elbow grease and a little bit of electrical skill and you can create your solar array for significantly less than commercially available options.
Emily Folk is a conservation and sustainability writer and the editor of Conservation Folks.
[Note: This was a guest post.]