Why Do Solar Panels Have a Peak Power? (Guide with Tips) - ShopSolar.com
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Why Do Solar Panels Have a Peak Power?

why do solar panels have a peak power

Short on Time? Here’s The Article Summary

The article discusses peak power in solar panels, explaining what it is, how it's calculated, and why it's important. Peak power is the maximum power a solar panel can sustain over a short period, usually measured in a laboratory under controlled conditions. This rating helps determine the panel's efficiency and suitability for different applications. Factors like panel orientation, cleanliness, and quality affect peak power.

Tips to optimize panel efficiency include hiring a certified installer, orienting panels correctly, choosing high-grade panels, using anti-reflection coatings, reducing unnecessary power draw, improving power storage, addressing shade issues, and keeping panels clean. The article also mentions advanced methods to increase power output, like light concentrators and trackers, though these are typically more suitable for large, ground-mounted arrays.


In our mission to make understanding and using solar energy simple, we address common issues and queries that our customers have. One of these is the matter of peak power. But why do solar panels have a peak power? More importantly, what is it and what does this mean for you? 

In the guide below, we answer all these questions and more. You will learn how peak power is calculated and why this rating is important. We also included some tips on you can optimize your solar panels to be as efficient as possible. 

Do Solar Panels Have a Peak Power?

If you’ve recently purchased one of our solar panel kits for your home, you made an excellent choice. Solar power is a renewable, sustainable, and clean energy source. But you may have heard about “peak power” and are wondering how that relates to solar panels. 

do solar panels have a peak power

Yes, solar panels do have peak power. It is rated under controlled conditions, but residential solar panels are subject to various influences which can affect this power output. 

So first, let’s take a closer look at the peak power of solar panels, and how it is calculated.

What Does Peak Power Mean?

Peak power is the term used to describe the maximum power that a power source can sustain over a short time. For those of you who are new to solar energy, here is a nutshell version of how it relates to solar panels. 

Solar panels contain cells that harness the energy from sunlight. This is called the photovoltaic effect. But these solar panels produce AC, not DC and this is stored in batteries. Because the grid operates on AC, an inverter converts the DC electricity from your solar panels into AC power for your home. 

To best meet your power needs, you may choose a panel with a suitable peak power rating. This peak power differs from continuous power though, which describes the amount of power it can continuously supply. 

How Do You Calculate Peak Power? 

Most homeowners choose a grid installation, allowing the home to obtain electricity provided by the grid supply as well as the solar array. But it is necessary to determine what the peak power of a solar panel is, for when your solar installation will be under a heavier draw of power. 

This is more relevant in cases of full off-grid installations. But it is just as vital in situations when there is a total power failure of the grid. Because your home will then be reliant on what your solar array can provide.

why do solar panels have peak power

All solar panel manufacturers must adhere to the standardized test formulated to test the kilowatt peak (kWp) of solar panels. This test includes standardized radiance, temperature, and size and is expressed as solar radiation of 1,000-watts/m 2.

External Influences OnPeak Power

Solar panels are subjected to rigorous tests before being sold to the public, and several variables are measured. They provide the answer to basic questions like whether solar panels reflect heat

Other important questions that are asked are  “How much heat and light do they reflect?” and “ How does temperature affect the solar panels?”

But the panels are mainly tested for the efficiency of the photovoltaic cells to absorb energy that can be converted into power. And as the sun’s light energy is the main external influence on peak power, a test was devised to measure this. This test is now standard for all solar panel manufacturers.

Testing Solar Panels for Peak Power

The peak power of solar panels is measured in a laboratory under highly controlled conditions. 

Conditions required for this test are: 

  • Exposure to overhead light at an intensity of 1,000 watts/m2. 
  • A standard air mass (AM) of 1,5 represents the relative length of the optical path through the atmosphere. 
  • Solar cells are exposed to a temperature of 25°C.

The reason for this particular light intensity is that it mimics the effect of the direct midday sun on a cloudless summer's day.

do solar panels have peak power

Nominal Power vs Real Power

Other terms that you may have heard are “nominal power” and “real power”. You must understand the difference between the two.

Your solar panel, once subjected to the test described above, will be given a peak power rating.  This is the maximum electric power of your photovoltaic system and is also referred to as the nominal power rating. This rating will remain the same, regardless of location.

The real power, however, is location-dependent. Because the real power is reliant on the number of sunlight hours your panel will e exposed to. This can differ widely from region to region. 

Optimizing Solar Panel Efficiency

You cannot usually affect the nominal power rating assigned during testing. But it is possible to optimize the solar panels for increased real power. And there are several ways in which to achieve this, depending on your location and setup. 

The slope or angle of your rooftop solar panel setup, orientation, and general weather conditions are all factors that influence real power. This is because the angle of your solar panels will affect their exposure to light, which determines how much energy is collected.

But this is only one aspect of how you can influence the power output of your solar panels. We have compiled a list of tips to help you maximize your solar panels’ efficiency. Let’s go through these tips now.

Helpful Tips to Maximize the Efficiency of Your Solar Panels

Solar panels are fairly easy to install and operate when you know the basics. And just as there are ways to decrease solar panel inverter noise, there are ways to increase solar panel power output.

It is much easier than you think to maximize the real power output of your solar panels. Simply read through these tips and apply these simple tweaks, where necessary. 

does solar panel have peak power

Hire a Qualified Solar Technician 

Perhaps you do not feel confident enough to install your own solar panels. Or maybe you simply want to ensure that they will operate to their maximum potential. Whatever the reason, it is best to choose an installer certified by the  North American Board of Certified Energy Practitioners (NABCEP).

A properly certified technician will be able to assist you with all matters pertaining to solar panel installation. The wiring of the panels, inverter choice, and also the panels’ mounting and orientation play a role in the efficiency of your system. So don’t proceed if you are at all unsure of what you are doing.

Orient Panels According to Your Location

The Us is located in the northern hemisphere. This means that the sun is always in the southern half of the sky. Because of this, solar panels in the US should be oriented south to increase exposure to sunlight. 

Facing solar panels in another direction will reduce the sunlight exposure, which in turn will reduce your solar power output. But if this requires you to install your solar panels in a way that is not safe rather consult an expert. There may be ways to fix the problem and still ensure a safe and optimal installation. 

Choose A-Grade Panels

Panels that contain A-grade monocrystalline cells are more efficient than lower-grade ones. In warmer weather, monocrystalline solar panels deliver higher efficiency. This is because of their higher temperature coefficient, which means that they have higher resistance.

Opt for Anti-Reflection Coatings 

Not only do solar panels reflect light, but more than 30% of the sunlight is reflected. And therefore it is not absorbed and converted into solar energy. But anti-reflection coatings prevent this loss. 

does solar panel have a peak power

Reduce the Draw

This may seem like a no-brainer, but unplugging items, not in use and turning off lights when not needed, will reduce your energy consumption. When your reliance on your solar system is increased, or you go off-grid, these unnecessary drains on your power will impact your entire energy supply. 

Using electrical appliances unnecessarily or leaving all the lights on will drain the power stored in your batteries much more quickly. So only use what you need when you need it, and you’ll improve the overall efficiency of your system.

Improve Power Storage

Ensure that you have adequate batteries for storing the power from your solar panels. Whatever is not properly stored, will be lost.

So invest in proper backup batteries for your solar energy system, and position these close to where your panels are situated for optimum performance. Remember, proper equipment and correct installation go are essential for a well-performing solar array.

Address Shade Issues

If your solar panels are in shade from nearby trees, they will not be as effective. So if you can cut back these trees, this will make an instant difference to the efficiency of your panels. 

If this is not an option for you, installing microinverters can address the shade issue for you. The problem with having some panels in shade is that it will reduce the overall efficiency of your array. But when each panel is fitted with its own microinverter, this problem is instantly resolved.

Keep Them Clean

Solar panels operate at their peak efficiency when clean. You’d be surprised how much dust, dirt, and debris they can be subjected to up on your roof. You should only need to do this 2 or 3 times a year. 

peak power of solar panels

Use water and a non-abrasive sponge only. Do not use harsh chemicals, and don’t use a power washer thinking it will be quicker and easier. This can cause irreparable damage to the cells in your solar panels. Hire a professional cleaner if need be, but make sure that you inform them of this issue first.

Other Important Factors that Increase Power Output

There are several ways in which solar panels can be rendered more efficient. But not all of these are viable for residential roof-mounted solar panels or smaller arrays. They are, however, quite effective and so deserve a mention. 

Light Concentrators

Solar panel output power may however be increased via a light concentrator. This is generally only used for a ground-mounted solar array. A mirror or Fresnel lens would be an example of this. But the lens has to be much larger than the panel. 

Light concentrators may not be practical for all types of solar arrays, particularly large ones. And the orientation of the mirror or lens can create even more technical difficulty. That being said, power output can sometimes be increased by up to 50% in this way. 

Light Trackers

This too is usually only feasible for a ground-based solar array. A tracking system allows your panels to track the sun and absorb more rays. This is useful in areas that receive less light, but it can be quite an expensive solution. 

Unless you are situated in a region that receives inadequate sunlight, this won’t be necessary. Rather consult a specialist to determine the optimum orientation for your location. This will make a big difference to your solar panels’ performance, and without the hefty price tag.

peak power of the solar panels


Here at Shop Solar kits, we believe in providing everyone with access to the benefits of solar power.

But knowledge is by far the greatest form of power. And now you have a deeper understanding of what peak power is, as well as what real power is and how to maximize it.

We are your one-stop shop for solar energy products as well as solar-related tutorials and insights. So contact us today for all your solar needs, made simple.

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