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A Complete Review of SunPower Solar Panels

Updated: Feb 15, 2022

SolarKobo Score: 4.9/5

Manufacturer's Profile

SunPower Corporation is an American company that specializes in the design and manufacture of solar modules. The initial technology and ideas that led to the creation of SunPower were incubated in the research lab of a Stanford University electrical engineering professor. On April 24, 1985, the company was officially incorporated by its founders Richard Swanson and Richard (Dick) Crane as EOS Electric Power. Three years later, the two founders were joined by a third and the company became SunPower.

SunPower's achievements in solar cell technology research has made its Maxeon brand one of the world's leading brands and by far the leading brand of panels in the United States. SunPower makes what are by the consensus of industry professionals, the crown prince of the solar module industry and backs its panels with an exceptional 25-year warranty.

In November 2019, SunPower announced plans to separate into two independent, complementary, strategically-aligned and publicly-traded companies – SunPower and Maxeon Solar Technologies (Maxeon Solar). Each company will focus on distinct offerings built on extensive experience across the solar value chain. This means that SunPower will no longer manufacture solar panels while the new company, Maxeon Solar, will continue to be a solar panel manufacturer. In other words, the SunPower brand will be replaced by Maxeon Solar.

Maxeon™ Solar Cell Technology

Since 2007 when it first began production, SunPower uses a next-generation cell technology, Maxeon™, in the manufacture of its panels. Now in its fifth generation launched in 2019 as the Maxeon Gen 5, the Maxeon™ cell technology is a variant of the IBC (Interdigitated Back Contact) cell technology.

Unlike the common monocrystalline and polycrystalline solar cells which has fingers or ribbons mounted on the front of the cell to collect the current generated by the cells, IBC cells has their fingers integrated instead on the rear side of the cell clearing the front of the panels of the thin grid lines found on the surface of panels made using the traditional cell technologies. (They are also known as 'back-contact' cells.) Removing the front fingers and solder bonds found in conventional cells is a way of increasing efficiency because these fingers and solder bonds can block the cell areas exposed to the sun. Additionally, these fingers can also deteriorate over time and lead to cell failures and power deficits.

In the design of the base IBC cell itself, SunPower uses a grid of N-type and P-type silicon on the rear side. The back-contact IBC cells are built on a base of high purity N-type silicon which also increases performance and has the low degradation rate which justifies SunPower offer of the leading performance warranty of 92% retained capacity after 25 years on two of its third generation panels and on the fourth generation Maxeon™ Series.

Maxeon™ adds a metal backing of solid copper underneath the cells to make them resist corrosion from elements and to make the entire module more durable by offering more strength to the silicon wafer. SunPower encapsulates its panels in an anti-reflective glass that reduces glare and losses that come from the cells themselves reflecting away up to 35% of the sunlight that falls on their surface.

SunPower/Maxeon offers its panels in a signature super-beautiful all-black colour, clean, un-cluttered and elegant design aesthetic designed to blend harmoniously into any roofing and architectural styles.

A Maxeon Solar Cell Structure (Source: Solar Quotes)

Range of SunPower Solar Panels

SunPower offers four types of solar panels made from its Maxeon™ cell technology that are optimized for different applications.

A Series

Upgraded in 2020, SunPower's A-Series panels use Maxeon™ Gen 5 solar cells, which are 65% larger than previous generations of Maxeon™ cells. This means that they can convert a higher amount of sunlight into electricity while taking up less space. These panels have efficiency ratings of up to 22.3%, putting them well above the industry average of 15-20%. SunPower delivered the world's first high-power solar panels in this series. (A high-power solar panel is a panel that has power rating above 360W.)

X Series

The start-of-the-art X-Series, SunPower's traditional module, offers up to 22.8% efficiency and maximum power ratings of up to 370W per panel for residential panels and up to 470W for commercial panels. The highly efficient panels are built with the 96-cell format to deliver more power than traditional panels with less space.

SunPower offers three panels in this series, the X20, the X21 and X22. The model numbers represent the efficiency with the base model X20 being just over 20% efficient, the X21 with a maximum of 21.4% efficiency and finally the X22 tops the range with an impressive 22.2% maximum efficiency.

Enphase Microinverters

Both SunPower’s A-Series and X Series panels integrate Enphase in-built microinverters. When a solar panel is fitted with a micro-inverter, it is then able to produce AC directly. In that case, they become 'AC solar panels' rather than DC solar panels. (Some solar panels come with a factory-installed micro-inverter. (Read more here.) These types are referred to as 'AC solar panels'. This means that they can be used directly without installing any inverters. It also means that they can produce more power per square foot than any other solar panels that are commercially available today.

Maxeon 2 and Maxeon 3

With the transition from SunPower to Maxeon, the latest generation panels from SunPower named Maxeon 2 and Maxeon 3 has replaced the E and X series. However, they are still available in the market and will be so for a while.

The Maxeon 2 and Maxeon 3 are both made from the Gen 3 IBC cell technology. They both use 104 cells in one module, an upgrade from the 96-cell format used in the A and X Series. This increases their output rating with a 20.4% maximum efficiency. The Maxeon 2 made from the slightly lower IBC cell, have a lower power rating of 340W to 360W, making them also much more affordable but still some of the most powerful residential panels available.

The Maxeon 3

E Series

The panels in traditional E Series were made from SunPower used the Maxeon IBC cells and offer an extremely high-performance warranty with an impressive 88% retained power rating after 25 years. They are designed in the 96-cell format. The original panels in this series come with power ratings of 20W, 327W and 435W and efficiency ratings of 20% efficiency.

The upgraded E Series have the latest panels in the series made from the Maxeon™ Gen 5 solar cells. With efficiency ratings of up to 20% efficiency, they come in 320W, 327W, and 435W options. They are the workhorses of SunPower’s line-up, designed to deliver consistent, worry-free energy over an exceptionally long lifespan.

P Series

Panels in this series use front-contact cells, as opposed to the back-contact traditional Maxeon cell-based technology used in other series. The P-Series are built with SunPower’s unique shingled 'hyper' solar cells. (In a shingled cell, a full size cell is cut into 5 or 6 strips and layered in a 'shingle' configuration. In this still emerging technology, the gaps between cells are removed, and more silicon cells crammed into one module thus increasing power output and module efficiency.) The shingled hypercell structure allows the fitting of more active cell areas into each panel, boosting power and efficiency without necessary increasing the size of the panels.

Panels in this series deliver up to 19% efficiency in panels with power ratings ranging from 380W to 400W. P-Series panels are designed for large commercial projects and they are engineered for maximum reliability and efficiency.

Maxeon 3

The Maxeon 3 is the new flag ship of the new Maxeon range which is expected to displace the older traditional series in the coming years. A high-power module, it is available in a range of output ratings from 370 to 400W for residential installations. They are manufactured using the Gen 3 high performance IBC cell technology in a new 104 cell format that increases power output further. The Maxeon tops the efficiencies ratings of all SunPower panels and, as at December 2020, of all the solar panels in the market, with an efficiency rating of about 22.6%.

The Maxeon 3


SunPower/Maxeon offers a long term gold-standard 25-year product warranties against any defects in their products, which exceeds the standard warranty period of 10 years for most solar panels. The SunPower Complete Confidence Warranty covers the complete system protection, removal of a defective part and installation of a new part, and shipping. These are not covered by conventional solar panel warranties.

For performance, the SunPower Complete Confidence Warranty guarantees a 25-year DC power decline of no more than 8% and 92% of the maximum peak performance at the end of the final year of the 25th year warranty, a significant leap over warranties offering by other brands which allow for as much as a 19.3% decline.

In Conclusion,

SunPower/Maxeon is the crème de la crème of solar brands for performance, sophistication and design with only a few competitors. Their consistency in research and innovation means that they are destined to remain the industry leader for many more years. Expectedly, they are insanely expensive. They cost up to three to four times the price of other brands found in the Nigerian market but it is as we say, better soup, na money kill am.

SunPower/Maxeon panels are not readily available in the Nigerian market and have to be imported. Expectedly, this will add to the cost of purchase. In any case, SolarKobo helps its clients in Lagos and throughout Nigeria make the best possible choice of solar panels, batteries, charge controllers and inverters. We help clients who wish to have SunPower panels imported for them. We also have university-trained engineers that provide the best installation on order.


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