How to Choose the Best Solar Panel Brand
Photovoltaic panels transform sunlight into electricity and form the photovoltaic panel of a residential or commercial solar energy system. They represent one of the leading equipment of this technology and are commercialized in models of different types, qualities, and prices.
If you install solar energy, you should pay close attention to the choice of photovoltaic panels (the correct technical term is a photovoltaic module) to achieve the best results with your solar panel.
However, it is impossible to determine the quality of a solar panel just by looking at its price as several pieces of information are equally or more important, such as its generation, how are they made and operation characteristics. For this, you must analyze the solar panel’s data sheet and other components, which can be requested along with your project budget.
With that in mind, I have prepared a list of the ten most important things to analyze when choosing your photovoltaic panels. Check out!
Power of photovoltaic panels
The electrical power of a solar panel (photovoltaic module) determines its electrical generation capacity and is measured in watts (W). The greater the control of the photovoltaic plate, the more electricity it can produce.
The main factors that influence the power of a solar panel are the quantity and quality of its photovoltaic cells, which can be manufactured with different types of semiconductor materials and/or use technologies that increase their efficiency.
In this way, it is possible to find several models of photovoltaic modules with different technologies, powers, and prices in the market. In residential or commercial solar energy installations, crystalline silicon cell photovoltaic panels with power between 340W and 540W are currently used.
However, the datasheet of a photovoltaic module presents different power values that you need to know to know what to expect from your solar panel generation. See what they are:
Maximum Power (Pmax) in STC
The nominal power achieved by the photovoltaic panel under Standard Testing Conditions, a model adopted worldwide in the labeling of solar modules, makes it possible to compare their quality. For this, the STC defines fixed values for the physical and climatic conditions that influence the production of a solar panel, which are:
Cell temperature = 25°C
Solar irradiation = 1000 Watts/m²
Air mass = 1.5
The maximum power in STC is the most used value in the solar energy market in the Philippines, as when they talk about the “size” of a photovoltaic panel, which is formed by a set of plates.
For example, if a website or vendor states that the solar panel is 2.38 kilowatt-peak (kWp), and it is composed of 7 modules, that means that each plate has a Pmax at STC of 340Wp (2,380 watts-peak / 7 = 340).
However, most of the time, the conditions of the STC do not match those where the board will operate, which means that its real power during operation is lower.
That is, even if the photovoltaic panels of your solar panel present a maximum power in STC of 300W, for example, this will rarely be reached during operation.
1. Power Tolerance (Power Output Tolerance)
For the result in STC, the manufacturer also informs the power tolerance of the photovoltaic plate, which is the interval between the maximum percentages of gain and loss that the module can record in its Pmax STC during operation. If you have a solar panel with + 10%/- 10% of power tolerance on a Pmax STC of 340W, this could reach between 306W and 374W.
Today, it is pervasive among the best manufacturers to have a negative power tolerance of 0%, which means that, under favorable conditions, the photovoltaic panel will always work with a Pmax STC equal to or greater than that specified in its datasheet.
Therefore, the ideal is to choose photovoltaic panels with zero negative and maximum positive power tolerance.
2. Maximum Power (Pmax) in NOCT/NMOT
The best manufacturers of photovoltaic panels also inform the equipment’s data sheet of its nominal power in NOCT or NMOT, both obtained in standardized tests that recreate environmental conditions closer to those registered in the installation sites.
Although they have different nomenclatures, Pmax NOCT (Nominal Operating Cell Temperature) and Pmax NMOT (Nominal Module Operating Temperature) define the maximum power achieved by the board. photovoltaic under the same conditions in the laboratory, namely:
Ambient temperature = 20°C
Irradiance = 800 W/m²
Air mass = 1.5
Wind speed = 1 m/s.
That is, the Pmax NOCT/NOMT is obtained with less sunlight and higher temperatures of the photovoltaic plate (which is usually 20° C warmer than the ambient temperature), two conditions that affect the efficiency of the module and reduce its power by about 25%.
Therefore, when checking the photovoltaic solar panel’s datasheet, consider the nominal power Pmax NOCT/NOMT as the closest to what you will obtain with the equipment on your roof.
3. The efficiency of the photovoltaic plate
When I talk about the efficiency of a photovoltaic panel, I am referring to the percentage of the sun’s light energy in Watts that transforms into usable electrical energy from the radiation that reaches its surface per m². That is, how many Watts per m2 the module generates energy.
For example, a 340W solar panel with 20% efficiency, under a standard irradiance of 1,000W/m², will generate 200W of electricity per square meter.
That is, the greater the efficiency of photovoltaic modules, the more energy per square meter they can generate and the smaller the amount of them needed to form the solar panel you need, a significant advantage for those who do not have much space on the roof.
However, the more efficient the photovoltaic panel is, the more expensive it tends to be. Therefore, if the solar panel’s price is important to you, it is worth calculating the cost per watt (PHP/W).
4. Temperature coefficient of photovoltaic modules (plates)
This data is essential for solar energy installations in the Philippines, as it shows how the photovoltaic solar energy panel will operate in warmer regions.
The temperature coefficient indicates the percentage of Pmax STC that the photovoltaic module will lose for every degree Celsius it reaches above its operating temperature in the laboratory, which is 25°C. The units of this coefficient are expressed in “%“ by “°C.“
For example, let’s consider a photovoltaic panel with a Pmax STC of 340W and a temperature coefficient of 0.38% / °C. Assuming that, during operation, the board reaches a temperature of 35°C, its maximum power will be 327.08W (340W — 3.8%).
That is, the lower this number, the better! Because on sweltering days, this results in less loss of power from your solar panel and, consequently, more energy production.
A high-temperature coefficient indicates that the solar panel is of poor quality. Today, the best manufacturers offer monocrystalline silicon modules with 0.3 and 0.4% efficiencies. Above 0.6% is a warning sign.
5. Types of photovoltaic solar panels
There are photovoltaic modules of different technologies on the market, each with advantages and disadvantages, including price. Today, the photovoltaic panels most used in residential and commercial installations are made of crystalline silicon (monocrystalline and polycrystalline), with the highest power, efficiency, and durability. When installing your project, ensure you are satisfied with the technology of your solar panel modules.
6. Durability and guarantee of photovoltaic panels
Photovoltaic solar panels are manufactured for long operating life and can generate energy for over 25 years, although they lose some of their efficiency over that period.
Today, the best manufacturers offer a guarantee of 25 to 30 years on the energy production of their modules and with annual efficiency losses of just 0.5%. That is, at the end of the useful life of your photovoltaic panel, it will still be able to operate with more than 80% of its original efficiency.
The warranty against defects can reach 12 years on the best-quality solar panels currently sold. At this point, however, it is important to think about questions about the manufacturer and the company that is selling your photovoltaic system, such as:
– Does the manufacturer have commercial representation in the Philippines?
– What does the installation company offer support in case of equipment defect?
– Will the manufacturer and installer still be on the market in 10 or 20 years?
7. Photovoltaic module (photovoltaic plate) manufacturer
There are hundreds of photovoltaic solar panel manufacturers worldwide, and the best equipment options available in the Philippines are still imported.
An internet search is an easy way to check the manufacturer’s quality of your photovoltaic panels. How is their website? Is there a guarantees section? Does he have an office in the Philippines? Are there any complaints about this manufacturer?
8. Quality of the photovoltaic panel’s aluminum “frame.”
A good indicator of the manufacturing quality of the solar panel is its aluminum frame, which provides robustness and integrity to the equipment. The best manufacturers use an anodized aluminum alloy for the frames of their solar panels.
Look at the corners of the frame, are they perfectly joined together? Has the frame been glued (not recommended), screwed, or welded at the corners?
If looks are important to you, look for a photovoltaic panel with a black anodized frame — they look great but can cost more.
9. The bottom layer of the solar panel (back sheet)
Traditional photovoltaic modules (photovoltaic plates) are manufactured with a white plastic film on the back called Backsheet, which protects the solar cells and acts as an electrical insulator. If the back sheet has air bubbles or signs of detachment, this is a sign of a poor-quality photovoltaic panel.
10. Photovoltaic module (board) bypass diodes
If your PV module is mono or polycrystalline silicon, bypass diodes (or pass diodes) are necessary. They prevent the formation of hotspots (hot spots), which can permanently damage the solar cells on the plate and compromise the overall production of the solar panel.
Typically, a bypass diode is used for each “series” of photovoltaic cells on the solar panel, which is placed on the back of the module. If the photovoltaic panels of your solar panel do not have bypass diodes, any shadow that forms on one of them, no matter how small, can affect the energy production of the entire panel.
Cost of photovoltaic panels
The apparent calculation to do is to calculate how many “Watts” per “PHP” you are buying. Remember, most of the time. You get what you pay for, so be cautious when choosing a PV array based on price alone.
However, it is possible to find promotions, and some suppliers have more competitive solar panel prices than others. Just be sure to compare correctly, considering the aspects presented in this list, such as power, efficiency, warranty, etc.
Note: the total cost of a photovoltaic solar energy system can be substantially affected by the difficulty of installation (the more difficult it is to install, the more expensive the labor and the final price of the project).
How many watts does a photovoltaic solar panel generate?
The amount of energy that a photovoltaic solar panel is capable of generating is directly linked to its technical characteristics (such as power and efficiency), its installation (direction and angle), and climatic factors (level of solar irradiation, shading, etc.).
Thus, we need to consider certain reference values to calculate the electrical generation of a photovoltaic module. Let’s calculate how much energy a solar panel generates in the Philippines using the following values as an example:
Photovoltaic panel Pmax STC power = 340 W
Technical losses (heating and dirt) = 20%
Daily average of useful solar irradiance = 5 hours
Based on these values, the daily amount of energy the plate generates equals its power, multiplied by the hours of sunlight and its yield. That is:
340 W * 5 hours * 80% = 1360 Watt-hours or 1.36 kWh.
To reach the monthly energy this photovoltaic module generates, multiply the value by 30.
1.36 x 30 = 40.8 kWh.
With this value, we can also calculate how many solar panels for residences would be necessary to meet the consumption of a house or the number of panels sufficient for a company. For this, we will consider a residence with a monthly consumption of 500 kWh.
If each module generates 40.8 kWh per month, divide the household’s monthly consumption by that amount to arrive at the number of photovoltaic panels in the solar panel:
500 / 40.8 ≅ 12
It is also worth remembering that the generation of your photovoltaic panel can be strongly affected if you do not maintain and clean the solar panels.
Best Solar Panel Brands and Manufacturers
In solar panels for installations, the most important thing is that the panels operate as long as possible without failures and power losses. “Premium” means reliability and high profits over 30 years. A solid warranty must back reliability, and a reliable brand and many tests must back the warranty.
I put together a solar panel ranking to help you choose the right solar panels, whether you’re looking for something cheap or high-end.
Solarwatt has the most extended product warranty in the world - 30 years. It also has the best warranty in the world - because it also covers transport and installation costs. So, if your priority is absolute peace of mind, you won’t find anything better than Solarwatt.
Meyer Burger is a production company from Switzerland. They produce photovoltaic panels and almost the entire fleet of machinery for producing photovoltaics. Their specialty is HJT photovoltaic cells (which have higher efficiency at high temperatures), connected using SmartWire technology (making them more resistant to microcracks) and inserted between two glass panes (making them last longer).
Unlike other brands that recently appeared on the market and offer a 30-year warranty, Meyer Burger has grounds to claim that its modules are reliable.
Risen panels are manufactured in five factories owned by Risen Energy. The company was established in 1986 and produced the first photovoltaic modules in 2002. Over the last six months, they have rapidly increased their processing capacity from 22 GW to 30 GW of photovoltaic modules. They have a wide range of products.
Jolywood is the world’s largest manufacturer of N-type monocrystalline cell modules, the TONCon subtype. These cells achieve higher efficiency, are more resistant to temperature, and will probably replace the commonly used PERC cells in the next few years. But purchasing modules is not only about hardware but also about distribution stability and customer service.
SunPower is a legend in the photovoltaic industry. Over 30 years of experience, more than 750 patents, a tremendous comprehensive warranty for 25 years, and the most potent photovoltaic panels on the market - it all sounds great. On the other hand, the giant has recently been struggling with financial problems. Is it worth investing in SunPower? Read the article and judge for yourself.
Viessmann is a large German manufacturer of heating and cooling systems, both for industry and private homes. They have many devices using renewable energy sources - heat pumps, biomass boilers, biogas installations, solar collectors, and photovoltaic modules. Renewable energy is not only part of their offer but also part of their vision - as evidenced by the fact that in 2012, they achieved the climate protection goal set by the government for 2050.
Hyundai-branded photovoltaic modules have been decorating house roofs for almost 20 years, so this manufacturer has considerable experience in this market. However, from such a brand, I would expect a premium product backed by the unshakable financial power of one of the largest corporations in the world. Still, in reality, things are a bit different.
LG Solar produced photovoltaic panels with a 25-year product warranty and used advanced technologies, including N-type cells and busbars at the back of the cell. This resulted in their high efficiency but also high price. LG photovoltaic panels also received distinctions in the prestigious PVEL and DNV GL tests.
The guarantor of the photovoltaic panels is LG Electronics, a South Korean giant associated with many business branches, most readily identified with broadly understood consumer electronics.
Photovoltaic panels are a long-term investment, secured by the manufacturer’s long existence and ability to fulfill the warranty after many years. Looking this way, finding a more stable company than LG is hard. Unfortunately, in 2022, “LG recently made a difficult decision to close its photovoltaic business to focus on other ventures.”
Sharp has over 55 years of experience in the production of photovoltaic panels. By 2010, they were one of the largest producers in the world. Their most important market is Japan. They produce most of the solar panels for Japanese satellites.
Tongwei is a colossal company whose primary business branch was the sale of fish products. A dozen or so years ago, they decided to enter the photovoltaic market and entered it on a grand scale, becoming the largest producer of photovoltaic cells in the world and supplying their products to such giants as Jinko, LONGi, and REC.
Then Tongwei started producing not only cells but also entire photovoltaic modules. In 2019, they were among the world’s top 40 most prominent producers. In 2023, they broke into the top ten. They probably dream of reaching the top.
Their flagship module is distinguished by a graphene coating, increasing performance by several percent in natural conditions, and a second glass pane on the back, protecting the cells better than standard foil.
Photovoltaic panels, commonly known as Recom Solar or Recom Technologies, are manufactured by the French company Recom-Sillia. Their headquarters, most important factory, and research center are located in the city of Lannion. The annual processing capacity there is 750 MW.
In addition to photovoltaic panels, they also sell inverters and energy storage units under their brand. Thanks to this, you can buy the entire installation from one guarantor, making things easier.
Seraphim is a Chinese company that produces photovoltaic panels. Established in 2011, it has sold 6GWp solar modules so far, and this number could quickly increase as its annual processing capacity is 5GWp per year. They sell panels in all flavors and types, even adding their innovations - overlapping cells in Eclipse series modules.
This is a Chinese brand of photovoltaic panels with Tier-1 status, which is part of the CHINT group, a Chinese electronics manufacturer. They have two factories in China and one in Thailand. In 2020, they produced panels with a total capacity of 4.2GWp annually. Although they are slightly behind the leaders, they are indeed huge numbers.
Trina Solar is one of the world’s largest producers of photovoltaic panels. Trina Solar comes from China but is not limited to the domestic market and remains one of the world’s largest and most recognizable manufacturers. It has 21 offices around the world. For over two decades, they have broken 18 records for the efficiency of various types of cells. They are also developing the idea of the Internet of Things to monitor and control the parameters of photovoltaic farms.
Winaico is a family-owned company from Taiwan, producing approximately 200 MW of modules annually. Winaico has been producing modules for many years and only has one factory. That’s good. There are situations in which Chinese manufacturers have several factories, one producing first-class equipment and the others not. With Winaico, you don’t have to worry about this.
REC’s headquarters is in Norway, and the operations center and factory are in Singapore. The company has been operating since 1996, and since then, it has gone from a small factory with manual production to a fully automated factory in Singapore.
The brand was initially called Renewable Energy Corporation - but now it is known simply as REC Group. At the end of 2017, REC had produced over 7.6 GW of panels. The most crucial change in the company’s policy in recent years is the increase in product warranty to 20–25 years for all products. REC is entirely focused on the photovoltaic market, but as it is part of a larger group, it has a more stable financial background.
Jinko was founded in 2006 and has since made a massive leap from nothing to the world’s largest manufacturer of PV panels. Their representative in Europe is Jinko Solar GmbH, based in Germany. They produced excellent and cheap modules, and since 2021, they have been conquering the market with modules with N-type cells - until recently associated only with the American SunPower and the Korean LG.
Jinko is probably the world’s largest manufacturer of photovoltaic panels. Their products gain the attention of photovoltaic farm investors worldwide, combining low prices with reasonable quality. Is it worth installing them?
Sunport is a reasonably average-sized company that contributed to developing photovoltaics by patenting the MWT technology. They produce decent panels at reasonable prices. Sunport was founded in 2012 by a team led by Dr. Znang Fengming, a professor of physics related to photovoltaics.
The scientists immediately presented their solution to the problem of busbars partially covering traditional cells. Then they implemented it, thanks to which they are the first and still the largest manufacturer of MWT panels (more about them below).
Canadian Solar modules are produced in Canada. Canadian Solar belongs to China’s league of solar industry champions. Many years on the market, sound financial, PVEL results, and many offices worldwide speak well of this brand. Canadian Solar cannot be called an innovation leader; its modules do not reach the premium shelf. Still, if you are looking for solid quality at a reasonable price, this is one of the best propositions on the market.
FuturaSun is an Italian manufacturer of photovoltaic panels that started operating in 2008. At an unfortunate moment, the demand for photovoltaics in Italy began to decline and almost disappear. However, as the country’s more prominent players left the business, FuturaSun endured difficult times partly because of its foreign customer focus.