As an Amazon Associate, this site earns commissions from qualifying purchases. For more details, click here.
If your roof does not have enough space for a solar array, ground mounted installation is the best option. But the question is, how far can solar panels be from your house or say, a barn? This is a question you need to answer prior to any setup. If it is too far you won’t get the desired results, so what is the acceptable limit?
You can install solar panels 500 feet away from your house, but this is going to require long, expensive wires to prevent energy loss. A distance of 50 feet or less will keep the voltage drop to 2%, which is the current acceptable limit. .
How Distance Affects Solar Panel Output
There are many reasons why solar panel ratings and actual output differ, but when it comes to distance, it is all about the wiring. The further the solar panels are from your house, the longer the cables have to be to prevent too much energy loss. Lon, thick cables are expensive and defeats the purpose of going solar, which is to save money.
If you can keep the distance at 100 feet or less, the energy and voltage drops will be at 3% or lower. If it is more than a 100 feet, you will need longer, thicker cables.
As current flows in an electric circuit, voltage is lost due to wire resistance. Longer cable wires produce more resistance hence greater voltage drops. With solar panels you want to maximize output, so use the shortest possible wire for the installation.
According to the National Electric Code, the voltage drop should be 3% or lower. A distance of 100 feet between a solar panel and house could result in a 3% or less voltage drop, which is acceptable. As you go further and reach 900 feet and beyond, the drop could 3.7%. That is assuming you use large, thick wires. Thin, flimsy wires could see the voltage drop much higher.
Lastly make sure you use only high quality cable wires. We recommend the WindyNation 10 Gauge AWG Cable Wires a it works great with solar panels .The maximum distance is 115 feet, which is right at the acceptable limit to minimize voltage drops.
How Far Can Solar Power be Transmitted?
Theoretically you can install the solar panels from any distance as long as you have enough cable wires. If you are willing to use longer, thicker wires then you can set the panels hundreds of feet from your house.
Suppose you have a barn and want to run it on solar power. if the shed is 300 feet from your house, it is better to install solar panels on barn instead of using a 300 ft cable. If the barn is not strong enough to support rooftop solar panels you can always opt for a ground mount solar array.
Solar power produces direct current (DC) which is vulnerable to energy losses and voltage drops. The best way to prevent this is to shorten the distance from the panels to your house. A higher voltage solar system is ideal because they generate lower amps.
Lower voltage solar systems are more vulnerable to overheating because of the higher amperage. Long cables produce more heat so a 48V system is more appropriate. The longer the distance from the solar panels to the house, the higher the voltage should be.
How to Reduce Solar Panel Voltage Drop
While energy losses and voltage drops cannot be avoided, there are many ways to reduce them. The most effective are the following.
- Reduce the distance
- Place solar components near each other
- Configure the solar panels in a series
- Use thicker wire
- Use high voltage components
Cut the Distance From the Solar Array to the House
This is the most practical solution. If you cannot install solar panels on the rooftop, choose a ground location as near your house as possible, like a pergola. Unless you decide to do the actual digging, burying of wires etc., a solar company will do the work for you.
Talk with them and they will be able to tell you the maximum possible distance for the solar panel. They should also provide the wiring so you know it’s the correct size. This is the simplest solution as a professional installer will do the work to ensure optimum performance.
Aside from the distance, the solar panels should be placed near direct sunlight as possible. Install the solar panels so they face true south (if you’re in the southern hemisphere, direct the panels true north). Combine this with a short distance and your solar panel should perform adequately.
Install Solar System Components Near Each Other
Solar panels and batteries have to be the right distance to work, and the nearer the charge controller and batteries are to the solar panel, the better. You may even install a battery bank near the solar panel to store extra energy
There is plenty of debate about how close a battery bank has to be to the solar panel. But the short answer is as close as possible. This also applies to the charge controller and inverter. All these components are connected by wires, and the shorter the wires, the lower the voltage drop.
Inverter DC service panel wiring can be vulnerable to voltage drops, though in other cases it is the AC wiring that is susceptible. The circuit side that runs a higher voltage lowers the effect of voltage drops. So an inverter should be installed near a circuit’s low voltage end, minimizing the effect of low volts.
- Install the inverter near the solar panel if the solar panel DC voltage is less than the utility panel.
- Install the inverter near the utility service panel if the solar panel DC voltage is greater than the utility panel.
Placing the inverter, charge controller and other components outside with the solar array exposes them to the elements. You can place them under a pergola for protection. It requires extra work but you will get better performance from your system.
Configure the Solar Panels in a Series
Solar panels configured in a series increases the voltage but keep the current constant. So four 12V solar panels in a series will have 48V but the current remains the same. Solar panels in parallel increases the current but does not change the voltage.
To connect solar panels in a series, connect the positive terminal of one solar panel to the negative terminal of another panel. Repeat for all the panels in your array. There are cases where a parallel configuration is better, but in this instance, series is ideal. Your goal is to increase the voltage to offset any voltage drops due to the distance involved, and a series will do that.
A series configuration helps but it will only go so far. You must have high voltage components in the first place. If the distance is far, you are better off buying high voltage parts and configuring it in a series for maximum effect. There is not a lot of benefit in a series solar panel if the voltage is already low.
A series solar panel will boost the voltage, but it must be in the right location. Any solar panel regardless of size must always be installed with as much sun exposure as possible. If you have to move the solar panel some distance to get maximum sunlight, do it. You will be able to compensate for that by using thicker wires and high voltage parts.
Use Thicker Cable Wire
Thicker wires means more capacity, and more capacity equals less resistance. You pay more for large wires but you get better performance from your solar panels, which is a good tradeoff. You will need to do some figuring to find the right wire length for your solar panel, but it is necessary for optimum results.
Wire sizes are measured in AWG. The rule of thumb is the thicker the better, but you must also know the solar panel current (amps), voltage and configuration. For a 1kw, 120V solar panel configured in a series, an AWG 8 wire will keep losses at 3.7% loss at 900 feet. With an AWG 6 wire the loss drops to 2.3% which is acceptable.
That is only an example as the wire size for your system depends on the distance, the solar panel size and other factors. If you are not sure you should consult a solar panel provider for advice. With a good solar panel provider they will provide all the information necessary to find and use the right wires.
Install a high Voltage Solar System
Using large cable wires is only one step. You can do better by buying high voltage components for your solar array. With a high voltage set up you don’t have to worry about the energy losses as much. As you might expect these items will cost more, but it is an investment for the future.
There are solar products designed to work at high voltages, and it might be worth investing in them if you have to install a solar array from a distance. These systems are optimized to use maximum voltage for superior performance, even with long wires.
Before you buy one of these high voltage kits, make sure that it conforms with what you want to do. if you already have a solar panel, check if these components are compatible with your system. If you don’t have any set, it is best to buy from a single provider to ensure compatibility.
This is only a general guide because it will depend on what type of appliance you run on solar power and if you are on a grid tie or off grid system. The inverter design also plays a role in how it handles voltage fluctuations.
The most important part is to know how much solar power you will need, be it for a house, RV or boat. Give this information to the vendor and a lot of your questions will be answered. Of course you should make allowance for safety and expansion in the future.
Installing a solar array requires careful planning, but it begins before you buy the right component. In summary, choose as close a location as possible to your house and buy the thickest cable wire possible for the solar panel. Consult your solar company for the right sized wire and everything should run fine.
I am an advocate of solar power. Through portablesolarexpert.com I want to share with all of you what I have learned and cotinue to learn about renewable energy.