How Much Direct Sunlight Do Solar Panels Need? 

How Much Sunlight Do Solar Panels Need

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Solar panels work best when they get the most sunlight to power the whole system, but knowing how much sunlight solar panels need per day and whether yours are receiving it, is much harder to determine. Which begs the question, exactly how much sunlight do solar panels require? 

On average, solar panels need 1000W of sunlight per m² each day to run optimally, which can be achieved in roughly four to five hours of sunlight in peak sunlight. These peak hours determine the size and number of solar panels needed for the solar system. 

Solar energy allows property owners to save money while helping the environment. These crucial reasons inspire many people to have solar panels installed in their homes and commercial spaces. In fact, in Western Australia, about 3,000 residential solar installations happen every month. It shows that people are now more open to renewable energy technology.

If you’re planning to switch to solar energy, it’s best to get as much information as you need before investing. This article can help shed light on some questions you may be having. 

Do Solar Panels Need Direct Sunlight to Work? 

While solar panels work optimally under direct sunlight, they can still work without it. Solar panels utilise photons carried by direct and indirect sunlight to produce energy. The panels convert these photons into electric currents. 

In cases where there is no direct sunlight, the solar panels will harness the energy coming from indirect sunlight. However, performance will drop when the panels use indirect sunlight to produce energy. For the solar panels to reach their maximum input, it requires 1000 W per square metre of sunlight. This amount is only possible when there is direct sunlight and will depend on the size of the solar panel

It’s important to note that solar systems work through the sun’s light and not heat. Solar panels can harness the same energy from peak sun hours on a clear summer or winter day. They can also function in ambient sunlight during cloudy days or under a shade. 

How Weather Affects Solar Panel Efficiency

Contrary to common perception, solar systems can function even if it’s not scorching hot outside. However, the efficiency of the solar panel is another thing. It all depends on the amount of the panel’s exposure to sunlight. Solar panels will work in various weather conditions as long as there is still ambient light. 

Do Solar Panels Work in Cloudy Weather? 

While solar panels work best in direct sunlight, they will still function even when the light is partially covered with clouds. During cloudy days where the sun is partially obstructed, energy production decreases. The solar panels will produce 30 to 50% of the usual power generation output.

However, expect that they will generate less energy. Its performance all depends on the panels’ efficiency and quality. It is best to remember that the solar system can generate more power than you require during peak sun hours. You may use this surplus to provide additional energy during cloudy days if you have a solar battery.  

The solar battery storage retains this energy in a battery within the residential solar PV system. When sun exposure is not ideal, such as during cloudy days, the system will harness the stored energy. In this way, you get consistent access to the sun’s energy even when your solar panels aren’t generating electricity. 

Do Solar Panels Work on Rainy Days? 

Rainfall does not affect electricity production since sunlight can still peek through rain clouds. The solar panels will still absorb, convert, and provide the electricity needed to power your home. 

As mentioned earlier, energy generation depends on light, not heat. Energy production depends on how many clouds are covering the sun. Production is at 10 to 20% of the usual amount of energy output on cloudy or rainy days. 

Suppose the generated energy is insufficient to sustain a home’s operations during rainy days. In that case, the solar system can still utilise stored electricity from a solar battery. You will be able to continue your routine despite changes in the weather. 

Additionally, rainfall can help in your solar panel’s regular maintenance. It washes away the dirt and grime accumulated during the summer months. When solar panels are clean, they perform more efficiently. 

Do Solar Panels Work in Winter?

Solar panels still work in winter because they can absorb the sunlight that passes through the clouds. Because there is still sunlight during a winter day, they will still be able to generate electricity, although not as much as they would on a clear day. 

When temperatures are below freezing, solar panels can still harness sunlight and produce electricity during winter. These panels absorb energy from the sun’s light and not the heat. So, there’s no need to worry about your solar panels’ performance when winter comes. 

Solar panels are more efficient in cold environments. It is because, in lower temperatures, electrons are at rest. When the increasing sunlight activates these electrons, there will be a more significant difference in the voltage produced by the solar panel. Therefore, the vast difference between low energy (the cold temperature) and high energy (sunlight) creates more power, making the solar panels more efficient. 

The important thing during wintertime is that the sunlight still hits the panels. The panel’s position will dictate the amount of energy it can generate. The decrease in output is mainly due to shorter daylight hours or heavy snow during winter. Usually, there will be about a 10 to 20% decrease in production capacity. 

Will Solar Panels Work in the Shade?

Partial shading, whether from other structures or tree branches, will not cause energy generation to stop; however, it can reduce the energy generated by your solar panel system. 

Manufacturers have engineered solar systems to allow them to function even when there’s shading. Qualified installers will be able to design your system that can work around structural limitations, though you won’t get peak performance from your solar panels this way. 

Remember that solar panels depend on the light rather than the sun’s heat. So as long as there is ambient light, the solar panels will work. 

Will Solar Panels Work at Night?

Technically speaking, solar panels won’t work at night. The solar panels’ photovoltaic cells need sunlight to generate electricity. However, it doesn’t mean that your whole solar system won’t be able to provide you with power. 

Solar panels harness the sun’s energy to produce electricity during the daytime. However, you can install a solar battery to sustain your home’s power needs at night. The sun may not directly generate electricity when it sets, but your system will still have electricity to provide.

Solar battery storage is strongly recommended for any home solar system. It ensures that any electricity your solar panels generate during the day can be utilised later when the sun has set. 

How Much Sunlight is Needed to Power a Solar Panel? 

The average sunlight needed to power a solar panel is four to five hours per day. Several factors affect the amount of electricity your solar panels can produce in a day. However, your location has the most significant impact on the amount of power your panels can generate. 

The critical consideration is referred to as “peak sun hours”. It measures the amount of solar energy your area can supply every day. You can use this data to determine how much power your solar system can provide. The Bureau of Meteorology gathers readings and creates a report on the average solar radiation in a specific area. 

Due to its location and size, Western Australia is considered the sunniest state on the continent. Perth, for example, receives around 3200 peak sunlight hours every year. You can enjoy 5 to 11 peak sunlight hours every day, depending on your location in the state and the time of the year. So, it won’t be a problem making the most of solar panels in Western Australia, since sunlight is abundant in this part of the world. 

How to Get the Most Sunlight on Solar Panels

The efficiency of solar panels depends on several factors such as their position, the home’s location, and environmental conditions. They may not work equally; however, there are ways to improve their performance to achieve maximum output. 

Install Solar Panels in the Best Location

Your solar panels’ location and orientation depend on the architecture of your roof and where you live. Most of the panels in Australia face north to achieve maximum efficiency. 

In the Southern Hemisphere, the sun’s rays come from the north. Solar installers can also position the panels facing slightly to the east or west for optimal generation and increased coverage throughout the day.

Solar installations may have a few limitations, such as the amount of sunlight in a specific area and the property’s position. Some people may be concerned if their homes can harness enough sunlight to power their systems. However, professional installers and suppliers can work around these challenges.  

A reliable contractor will be able to determine the best location for your solar panels based on your home, your location and the solar panel dimensions. It is crucial to consult with a qualified solar installation company to maximise your investment. 

Install It at the Optimal Angle

Generally speaking, the best angle for solar panels is approximately 20 to 30 degrees. However, it can be reduced to 10 degrees if necessary. 

The best angle for solar panels actually depends on your location, as the sun’s rays will hit slightly differently even across Australian states and cities. However, the difference in angle won’t have a huge impact on your solar panels’ performance. 

Of course, the installation angle should also allow solar panels to clean themselves since the leaves and water will slide off during rainy days. 

Remove Obstructions

Obstructions can significantly affect the efficiency and effectiveness of your solar panels. Anything from signs to tree branches will reduce the amount of sunlight your solar panels can absorb, which will reduce the amount of power they generate. 

Solar panels are engineered to function best in direct sunlight. Suppose there are obstructions, such as another structure or trees. In that case, there might be a significant reduction in the solar system’s output. 

It’s best to remove or trim trees that can block your solar panel. A professional installer can work around structures such as buildings that cast a shade on your panels. 

Install Solar Tracking Systems

Solar tracking systems are devices that allow solar panels to move and follow the sun’s path. More power will be generated when the solar panels move where the sun is, as they will be getting more direct sunlight for a longer amount of time.

While more common in commercial and industrial solar PV systems, solar tracking technology can allow your panels to consistently optimise their angle throughout the day. 

Related Questions

How Does Temperature Affect Solar Panels?

Solar panels function best at temperatures between 15 degrees and 35 degrees Celsius. When the temperature is higher than that, the chemical reaction within the panel that turns light into power becomes less efficient. 

Can Solar Panels Work With Artificial Light? 

Yes, solar panels can produce energy from artificial light such as incandescent bulbs, as long as the light is strong enough. However, solar panels on the market today are engineered for sunlight, so can’t make usable amounts of electricity from artificial sources like light bulbs. 


This article is published in good faith and for general informational purposes only. JFK Electrical does not make any warranties about the ongoing completeness and reliability of this information. Always seek personalised advice on solar energy to ensure any recommendations suit your property and scenario.

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