Solar power is a wonderful way to generate electricity, but sometimes you need more than you have installed. If you already have solar on your roof or don’t have additional space, a ground-mounted solar panel array might be a good choice. Today, we are taking a look at ground-based solar panels and sharing how we built ours.
What Is a Ground-Mounted Solar Panel Array?
Solar panels are often installed on a roof as a convenient location to capture the sun. But there are situations when this doesn’t work. Ground-mounted solar panels are sets of panels installed on a rack or pole mounted on the ground. You will commonly see this in solar power farms, but smaller setups can be used on private property.
Why You Might Want Ground-Mounted Solar Panels
When building an off-grid or mobile solar power system, there may be situations when expanding the solar array is ideal. For an RV or a camp, a ground-based solar array may be a cost-effective way to quietly generate additional electricity for all of your power needs.
Ground-mounted solar panels also have a few advantages over rooftop solar. First, they allow for a lot more space for larger setups if you have the property. Second, they can be positioned and angled to get the most sun and least shading. Lastly, having ground access to the solar panels makes it much easier to clean and maintain them if necessary.
While our RV has a substantial solar system built on it, we like to plug into a bit more power when at our camp. To do this, we built a cost-effective external temporary ground-based solar system to plug our RV into. This expands our solar generation capability by 1200 watts, providing all the extra power we need.
Need a refresher on RV solar systems? Check out our Beginner’s Complete Guide to RV Solar Battery Chargers
How to Build a Ground-Mounted Solar Array
There are two primary types of ground-mounted solar panel setups: temporary and permanent. You will want to determine which type you need to install prior to beginning.
A temporary setup will be used for a camp or RV spot not used full-time, while a permanent setup will be for a home or cabin used year-round. This article is focusing on temporary arrays for expanding solar systems. However, you can scroll down for some things to think about with permanent installations as well.
DIY Temporary Ground Solar Array
We built a 1200 watt temporary ground solar array that we plug into when we take our RV to our property. This article addresses many of the questions we receive about our setup. To build a ground-mounted solar panel array, the following needs to be considered:
What Panels Are You Using?
We built our ground array with cost-effective residential glass solar panels. These panels are 300 watts and cost us $150 apiece. Knowing your panel size is an important first step in building a ground-based array.
Determine Your Solar Panel Angle
When building your ground-mounted solar panel array, you need to determine the angle for best performance. If this is a temporary system that will only be used part of the year, you should optimize for that time of year. A few tools can help you do this.
First, Suncalc.org is an easy way to select the time of year and move the sun through the day at your location. This will give you the sun angle. Secondly, you can use PVWatts to figure your actual solar output based on month and panel tilt. Our sizing article walks through how to use this tool.
Building the Array
For a temporary array, you usually want it to be cost-effective, easy to build and disassemble, and portable. Stary by drawing out what you think your design might look like.
While your needs may be different than ours, we found that a simple set of triangles built from 2×4 timber was a great solution.
After a bit of geometry, we determined that we needed two 8 foot sections for the back 90-degree pieces. One 10-foot piece of wood supported the panels. We moved our primary angled piece around until we got the right angle using an angle finder. Then, we screwed the wood together with two wood screws per joint and replicated the triangles by laying the next set on top and building out all of them.
With two people, we stood up the triangles and installed a cross member to hold them together. This cross member also served to hold the bottom of the panel up while we secured them. Simple rafter ties mounted to the wood and bolts secured the panels to the triangles.
We built two sets of 2 panels with 3 triangles each. Once complete, we were able to drag the array into position. Then we secured them together with cross members and a few screws.
The forest shelters our location from high winds, so we did not anchor our ground-mounted solar panels down. However, you may want to anchor your array if you expect the wind to be an issue.
After we installed our panels, we built a junction box on the back of the array. Since our array was about 100 feet from the charge controller, we wired our panels in a set of series-parallel to get around 80 volts.
We used a simple electrical junction box and terminal block to make the wiring connections. We also used cable glands for all wiring penetrations. Then we made sure to leave an MC4 set of connections on the panels so that we could make the final connections with the connectors and would not have to work in a hot electrical box.
Solar Panel Junction Box
Here are the components we used to build our junction Box
We installed a disconnect and fuse at the charge controller end of our connection as well. Your array voltage and current will determine the size of your fuse.
WARNING: BE CAREFUL when working with live panels. Do not attempt to wire higher voltage panels like these if you are not confident in your electrical abilities. If you want to attempt it but are unsure of potential shock risks, cover the panels or make the connections at night. As a result, the panels will not be producing and will not pose a shock hazard.
How Well Does a Temporary Ground Array Work?
Overall, we have been very happy with our array’s performance. It expands our solar system to 4kw when we hook up. This enables us to run our AC and even slowly charge our electric car when we have excess power.
In the fall, when we are done using the array, we remove the ground-mounted solar panels and store them. However, we leave the junction box and framing intact for next year. Setup and takedown take about an hour, and the entire build took us about a day, including design and getting supplies.
What About Permanent Ground Solar Arrays?
First when designing a solar ground array for a permanent structure find out if you need to get a permit and inspection from your local authority. Be sure to know permitting and inspection requirements before embarking on this project, as you may need to have your design approved before beginning.
Permanent ground arrays come in two main types: pole mounts and rack mounts.
Pole mounts install panels on a single, tall pole affixed in the ground. This style gets the panels up higher and sometimes is adjustable to account for different sun angles through the year.
Rack mounts are typically lower to the ground. They consist of multiple ground mounts and the panels are mounted to a rack.
Both pole and rack mounts are installed in a permanent location, so deciding where they should go is critical. Choosing a location with the best sun exposure and least shading is ideal.
Permanent ground-mounted solar panels can be built out of wood or metal and will usually have a conduit running between the panels and junction box. Some permanent arrays have outdoor grid-tie inverters mounted underneath them or utilize micro inverters on each panel if they are grid-tied panels. If the permanent array is used for an off-grid application, array voltage and electrical run length are critical requirements in the design.
When designing a permanent ground-based system, selecting the correct angle is once again critical. If the array is not adjustable, you will need to determine if you want to optimize for summer or winter performance. Using SunCalc and PVWatts, as mentioned before, will help you make the right decision.
A Great Way to Increase Solar Capacity
If you have space, a ground-based solar array can be a great way to increase your solar capacity, temporarily or permanently. With easy access to the panels, no holes to drill in your roof, and relatively easy construction, a ground-mounted solar panel array might be the right choice for you.
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