Solar Panels

Over a thousand of solar panel factories operate in China and provide a wide offer of solar panels, not all of them quality being trustworthy. 


Nowadays the PV manufacturing market is disrupted by many changes and the quality follow-up is destabilized: quick growth of the demand, rise in transportation price, rising price of cells and glass, brand that manufacture in pop-up factories to balance with the demand, and the quick change in solar cells size are the main reasons of this disruption.

With 5 years of experience in solar energy, Greenwire’s team go in quality control and analyzes new manufacturer every month, it allows us to keep up to date with the latest innovations within the market and to propose you the best of what China can provide.

Greenwire through its experience of quality control over the years, can advise you the best brands found on the market, or advise you high quality factories to manufacture the panels on your own brand. We can advise you a various selection of PV to find the best solution that will suit your project or your distribution quality standards.


360° Service

Thanks to our team that is available to advise you for your project, design the layout, ship the goods, and help you for the aftersales service, we make your sourcing as efficient as possible. Greenwire’s team will assist you during the whole process.

Our team is here to answer all your technical questions as well as to prepare you the right materials. Our company’s inspection follows strict IEC standards, and we make sure that every panel is then inspected to meet the specified standards.

Premium solar panels require quality bill of material (BOM) and high-end production machine. Greenwire is here to inspect and validate these two conditions for you to acquire a product conform to the specification sheet.

Original poly and monocrystalline solar cells

 The key component of a solar panel is the solar cell, also known as waffer. It’s the component that will define the efficiency of the panel and its durability. The price of a solar panel will mostly be defined by the quality and type of solar cell used. Three type of cells can originally be found on the market: polycrystalline, monocrystalline or Thin film cells. 

Monocrystalline cells are made of a single silicon crystal layer. Polycrystalline cells panels are a PV made of multiple silicon crystal fragments that are melded together during manufacturing. 

Monocrystalline panels usually have greater efficiency than its sister the polycrystalline cell. Monocrystalline solar panels can handle better shading. If a three or an objects shad es an area of the solar panels, the efficiency will be less impacted.

Polycrystalline have lower performance in temperate climates so they are mainly used in very hot countries. In another hand, polycrystalline tend to be cheaper. 

Overall, polycrystalline solar panels tend to be less and less manufactured and installed worldwide, as the price between poly and mono technologies are becoming similar.

Thin film cells are a special type of cells use mostly for its capacity to be mechanically flexible. They can be applied on existing surface such as boats or RV or can simply be transported to be use with portable generator.

PERC and Bifacial solar cells

Two different technology of solar panels are now mostly purchased and installed around the world: PERC and Bifacial.

Having the same quality and inherited from the monocrystalline cell technology, they have high efficiency standards. We strongly advise you to choose between one of this two technologies for your projects. 

PERC cells

 PERC stands for “Passivated Emitter and Rear Contact”. They are indeed a monocrystalline cell, where an additional layer on the back is added. It helps reducing the reflection of the sunlight on the cell and helps generate a higher energy output as more sunlight is captured and turn into electricity. We calculated that about 5% more efficiency can be added using PERC technology compared to standard poly and monocrystalline cells.

Bifacial cells

  Bifacial cells is a PERC cell but with a layer of glass replacing the back surface of the cell. It allows that the sunlight reflected on the ground behind the solar panels be reflected at the back of the panel. The solar cells would get an extra sunshine as the sunray would go through the glass layer of the cell. In this way, even more energy is produced by the cell compared to the standard PERC cell. This technology come at a cost and should be considered for area where you would like to increase the efficiency of your system. They are mostly use in rooftop application or solar field using structure to elevate the panel from the ground.

Bifacial solar panels are not placed directly on a roof but fixed on a structure placed at a higher height. These modules produce solar power from both sides of the panel as they expose both sides of the solar cells.

Bifacial solar panels offer +10 to +30% efficiency compared to rooftops solar panels. 

Bifacial solar panels

Size of solar panel

Solar panel power and size depends on two factors: the size of the solar cell and the number of cells use.

Solar cells are available in many sizes. Because each cell requires a specialized production line, your supplier can’t manufacture all of them in their own factory. In 60% of the case for 2021, your PV is manufactured in a subcontracted factory. Greenwire offers you PSI quality inspection to be sure that your solar panel has been manufactured in your manufacturer premises.

 While the 156mm cell has been long used for solar panel since 2012, they are now phased out. They were standard crystalline cells mono or poly that were widely use in the production of panels between 290W and 340W.

 The introduction of the PERC technology for the mass production in 2018 bring in the meantime what the industry call “large square cells” of 158.75mm. Is therefore slightly increase the power of the solar panels from 290W to 330W for the 60 cells configuration and 340W to 410W for the 72 cells configuration.

In the early month of 2019, factories start to cut cells in half. It allows an increase in tension between cells and a slight increase in power output for the solar panels. The cell use at that time is the 158.75mm, the year fashion. Power output surge to 340W for the 120 cells configuration and 420W for the 144 cells configuration. The generical language adopted is the word “cell” to describe an actual half-cell. Since 2021, that 158.75mm size is less and less use and more manufacturers are starting to produce the next generation.

 In 2020 it’s a race that start between cell manufacturer to find more efficient cell with n ew sizes. A new generation of cell born: the 166mm cell. Wider and more efficient, they are used to manufacture two sizes of panels: 380W solar panel for the format 120 cells and 450W in the format 144 cells. They are the best seller that year for worldwide installation, even though European client for example, prefer to stick to the latest generation. 

 In 2021 two new size of cells appear on the market and are propelled by Tier-1 factories: 182mm and 210mm cells. Both of those two cells size in 2021 are used only for large dimension panels, used in solar field. 

 The 182mm cell is used in solar panel of 144 cells reaching 550W for a dimension of 2278*1134mm. 

The 210mm solar cell are used in solar panels of 660W for 132 cells, reaching a maxed-out sized of 2384*1303mm. 

 In 2022, the 166mm rooftop solar panel 380W is planned to phase out from Tier-1 brands. Therefor, manufacturers are turning to the latest 182mm cell to produce a new panel of dimension 1722*1134 with a peak power of 415W. 

Each of solar panels have different use and be adapted to your project, Greenwire will advise you on which solar panel size to use upon request.