Sunpower Review 2024
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Sunpower Overview
Since the launch of the high-performance IBC solar cells back in 2007, Sunpower has long been regarded as the world’s leading solar cell and panel manufacturer based on performance and efficiency. Now formally known as Maxeon Solar Technologies outside the US, Sunpower still produces some of the world’s most efficient solar panels based on the patented IBC cell technology and also boasts the leading performance warranty with a minimum 88 - 90% guaranteed power rating for up to 40 years. The more cost-effective performance or P series panels from SunPower also boast high quality and great performance backed by a 25-year product warranty.
SunPower Solar Panels Quick Summary
Power rating (W): 330W - 545W
Efficiency (%): Very high - 21.0% - 24.1%
Cell technology: Premium N-type IBC and shingled cells
Price bracket: Med to Very High $$$$$
Most efficient panel: Maxeon 7, 445W
Product Warranty: Excellent - 25 to 40 years
Service and support: Very good 5/5
Overall: Highly recommended ☆☆☆☆☆
Company background
SunPower Corporation has a rich history in solar manufacturing and has long been regarded as the solar industry technology leader. This is a very big claim, but it’s hard to disagree as they currently produce the most efficient residential solar panel, the Maxeon 3, with the lowest degradation and best performance warranty on the market. Although, like most things, high performance comes at a high price, and SunPower panels are some of the most expensive in the world.
SunPower started in a lab in the early ’80s and officially became SunPower in 1988. After securing funding from investors, the R & D team developed record-breaking PV cells using advanced cell technology, which were later used by the NASA space program along with Honda to win the world solar challenge car race in Australia. These achievements put SunPower on the world stage as one of the leading solar cell manufacturers and laid the foundation for the high-efficiency Maxeon IBC cells used today. SunPower has expanded and built advanced facilities in the US, Mexico, Europe, Malaysia, China and the Philippines to manufacture high-efficiency solar panels. However, it hasn’t always been smooth sailing. Over recent years, the company has run into financial issues. It racked up considerable debt due to high overhead costs and pressure from the highly competitive Chinese and Korean panel manufacturers. The financial troubles forced SunPower to restructure its business and manufacturing operations, and now the financial situation is looking positive. See detailed company analysis in this article from PV-Tech.
SunPower Splits into two companies.
In 2019, Sunpower announced it would separate into two independent public companies - SunPower and Maxeon Solar, each focusing on a different market segment.
SunPower will focus purely on the North American Solar market with distribution, sales and installation of solar panels, energy storage and associated products.
Maxeon Solar or ‘Maxeon Solar Technologies’ will become the global developer, distributor and manufacturer of the SunPower Maxeon cells and Solar panels range.
SunPower Solar Cell Technology
Maxeon IBC cells
SunPower began mass production of the high-performance IBC or Interdigitated Back Contact cells back in 2007 and has led the industry ever since using what is considered the most efficient solar cell technology available today. Unlike the common monocrystalline solar cells, which use front-mounted busbars and fingers to collect current, Maxeon IBC cells convert energy on the back side of the cell vis a solid copper layer integrated into the rear side of the cell. The IBC cell design increases efficiency in two ways: first, by eliminating the need for front exposed busbars that partially shade the cell, and second, due to the lower resistance within the cell due to the larger metal contact area in the rear side. Traditional solar cells with front-side busbars have to strike a fine balance between shading and resistance, whereas large front-side busbars reduce resistance but increase shading; this issue does not apply to IBC cells, which is why they are able to achieve such high efficiency. However, this cell design is more complex and expensive to manufacture, hence the higher cost compared to regular solar cells.
The SunPower IBC cells are built on a base of high-purity N-type silicon that further increases efficiency and performance and offers a very low rate of degradation; this is the basis of SunPower’s leading performance warranty of 88.25% retained capacity after 40 years on the Maxeon series panels.
SunPower Maxeon IBC cell construction diagram - Image credit Sunpower Corp
The current generation (3 & 4) IBC cells from SunPower use the smaller format 5” (125mm x 125mm) size configured in a 96-cell layout with 8 rows of 12 cells. Almost all other manufacturers have moved to the 6” (156mm x 156mm) cell size which makes up a common 60 cell panel. Cell size doesn’t affect performance, but more cells do equate to a higher voltage, which can be problematic for domestic installations with a voltage limit of 600V (depending on the country). A higher voltage means fewer panels can be linked together in a string before reaching the upper voltage limit.
For details on Enphase and SunPower compatibility and other questions, join our solar power forum.
Shingled Cells
Shingled cells are a proven technology that uses overlapping thin cell strips assembled horizontally or vertically across the panel. The SunPower P series panels, described in more detail below, use the vertical format with 6 long cell strips in parallel. This offers several benefits, including improved shade tolerance when partially shaded, as each long cell works independently. The thin shingled cells are also more flexible and less prone to micro-cracking, a common issue with conventional full-size square cells. These are made by laser cutting a normal full-size cell into 5 or 6 strips and layering them in a shingle configuration using rear-side conductive adhesive. The slight overlap of each cell strip hides a single busbar that interconnects the cell strips. This unique design covers more of the panel surface area and doesn’t require front-side busbar connections, which partially shade the cell, thus increasing the panel efficiency, much like IBC cells.
SunPower P series panels use P-type shingled cells - Image credit SunPower Corp
SunPower P series Shingled cell construction - Image credit SunPower Corp
The P series uses conventional P-type silicon, which is not as efficient as the high-performance N-type silicon used by the Maxeon IBC cells. However, it is much more cost-effective and still achieves a respectable efficiency of 20.4%. The P series is also backed by the SunPower 25 manufacturer’s warranty.
The SunPower Range
While the renowned Maxeon series panels are some of the world’s best-performing panels, SunPower's more cost-effective Performance series offers a diverse range of panels for residential, commercial and utility-scale solar installations. The Maxeon 2 and 3 series panels replaced the previous E and X series, which used the same high-efficiency IBC cells to compete in the premium end of the market. The latest generation 5 and 6 series (M-series) panels are AC panels with built-in microinverters from Enphase Energy. These next-gen panels feature a new larger cell design, making them the most powerful and efficient panels released by the company. The price-competitive performance or P-series panels use the unique overlapping shingle cell design and complete more in the commercial market.
Maxeon 2 - 340W to 360W
Maxeon 3 - 400W to 430W
Maxeon 5 Series - 390W to 415W
Maxeon 5 AC Series - 400W to 420W
Maxeon 6 AC Series - 415W to 445W (M-series in North America)
Maxeon 6 Commercial - 450W to 475W
Maxeon 7 Series - 435W to 445W (New) - Most efficient solar panel
Performance Series - 335W to 545W
Maxeon U Series - Rebranded Warree panels
Sunpower Maxeon 3 solar panel array on a rooftop on King Island in Australia - Installation by Hinterland Energy
Maxeon 3
The Maxeon 3 is the flagship of the SunPower range and is available in sizes from 400 to 440W for residential installations. The Maxeon 3 series is built using the Gen 3 level cells using a larger 112-cell format to increase power and tops the range with an impressive 22.8% maximum efficiency, making it one of the most efficient solar panels available.
Maxeon 3 – 112 cells – 415 to 430W - Monocrystalline IBC N-type cells
Maxeon 2
Like the Maxeon 3, the Maxeon 2 panel is based on the Gen 3 high-performance IBC cell technology and uses the same 104-cell format to increase power output further and tops the range with a 20.4% maximum efficiency. However, as it is based on the slightly lower-spec IBC cells, the Maxeon 2 panels have a lower power rating of 340 to 360W, making them more affordable but still some of the most efficient residential solar panels available.
Maxeon 2 – 104 cells – 360W - Monocrystalline IBC N-type cells
Maxeon 5 Series
SunPower’s next-generation A series AC panels and the new Maxeon 5 series are built on what Sunpower refers to as the Next Generation Technology IBC (Interdigitated Back Contact) 'Gen 5' cells. These new larger format 6” IBC cells are fabricated on a new line at its manufacturing plant in Malaysia. The new design is used to produce panels rated from 390W to 415W making them some of the most powerful residential panels currently available. The alternative A series version of the Maxeon 5 panel incorporates a microinverter from Enphase Energy.
Maxeon 5 series – 66 cell – 390 to 415W - IBC N-type cells (Gen 5)
Maxeon 6 Series
M-series in North America
In 2022, SunPower released the Maxeon 6 range. Known as the M-series in North America, they are built on the same 66-cell format as the five series but use the next generation Maxeon 6 cells to boost efficiency to 22.8%, putting them among the most efficient solar panels ever manufactured for residential use. The new 6 series panels are slightly larger than the five series, coming in at 1032mm wide by 1872mm high. Naturally, power output has also boosted with a 6% increase taking the peak power rating from 415W to 440W. Like the 5-series, the A series version of the Maxeon 6 panel incorporates an Enphase Energy microinverter. To cater for the commercial market, the Maxeon 6 will also be available in a larger 72-cell format with increased power ratings from 450W to 475W.
Maxeon 6 (AC) series – 66 cell – 420 to 445W - IBC N-type cells (Gen 6)
Maxeon 6 Commercial series – 72 cell – 450 to 475W - IBC N-type cells (Gen 6)
Maxeon 7 Series - Coming in 2024
Maxeon Solar Technologies recently announced the world's highest conversion efficiency for a solar panel, reaching up to 24.1% using the next-generation Maxeon IBC cells. These cutting-edge panels, known as SunPower Maxeon 7, have been operational in Spain since December 2023, marking the company's inaugural installation by Maxeon's Spanish partner, Lidera Energía, in Granada. The efficiency milestone is attributed to Maxeon's latest generation of Maxeon Interdigitated Back Contact (IBC) solar panels in a new 112-cell format. These panels come in three variations, delivering power outputs of 435 W, 440 W, and 445 W, with corresponding panel efficiencies of 23.5%, 23.8%, and 24.1%, respectively.
The SunPower Maxeon 7 series features an impressively low power temperature coefficient of just -0.27%/°C, down from the already low -0.29%/°C of the previous generation Maxeon 6 range and just shy of the lowest rating panels from REC. Similar to other Maxeon modules, the 7 Series boasts an impressive 40-year product and power warranty. Its annual degradation rate is just 0.25%, resulting in close to 90% of the original power rating retained after 4 decades of real-world use. The new panels are expected to be released in limited quantities globally by mid-2024.
Download the Maxeon 7 Series Datasheet
Sunpower Performance Series
As described in detail earlier, the Performance series, or P series panels, use a unique shingled cell design with 6 long strings of shingled cells in parallel. This design is more cost-effective and offers additional shade tolerance when partially shaded. The thin single PERC cells, based on standard P-type silicon, are more flexible and less prone to micro-cracking, which is a common issue with conventional full-size square cells. The P series is available in three varieties, with the smaller residential panels rated from 370W up to 390W, the larger format commercial panels available in 405W to 420W power ratings, and the extra-large utility size panels available from 475W to 500W.
P Series Residential panels - 330W to 390W - Shinged cells
P Series Commercial panels - 405W to 420W - Shingled cells
P Series Utility size panels - 475W to 545W - Shingled cells
Despite being based on standard P-type silicon, SunPower still offers an impressive 25-year performance warranty as well as a 25-year manufacturer’s warranty on all P Series panels.
Sunpower P series panels using shinged cells - Available up to 405W power ratings
Sunpower U Series
The U series is the entry-level panel from Sunpower, which is currently sourced from Waaree Energies Ltd, one of the leading Indian solar panel manufacturers. The Waaree Arka series are split cell panels rated at 380W to 420W featuring common Mono PERC cells. While a large reputable manufacturer makes them, they do not have the same efficiency or lifespan as the high-performance Maxeon series panels. The Waaree Arka series is backed by a 25-year warranty.
Warranty and service
In a surprising announcement, SunPower Maxeon Technologies decided to increase its product and performance warranty on the Maxeon range of panels from 25 years to an incredible 40 years, making it the industry's most extended solar panel warranty by a decade. The company is confident it can support the extended warranty based on a detailed failure analysis program which reported an extremely low 0.005% return or failure rate based on the warranty claim data from the 15 million panels sold over the last few decades.
The new 40-year warranty guarantees a minimum power output of 88.3% in year 40, meaning power output will only degrade by around 0.25% per year over the warranty period. Maxeon claims this is attainable due to the proven long-term reliability and performance of Maxeon IBC cells built on a unique patented metal foundation. This durable cell structure can withstand high thermal stresses and dissipate more heat, meaning they are not as suspectable to hot spot formation or micro-cracks, a common problem with the standard cells most competing panel manufacturers use.
The Sunpower Performance or P series panels are backed by a 25-year product warranty guaranteeing a minimum of 87.2% power output after 25 years.
The new 40-year Maxeon (SunPower) Performance warranty - Image Credit Sunpower Corp
Download the full SunPower Maxeon warranty certificate here.
Sustainability
SunPower has long been the industry leader in sustainability and is the only manufacturer we know of that uses a full closed-loop sustainability strategy. SunPower’s philosophy is to drive sustainable business practices at every stage of the product life cycle and beyond. This strategy paved the way for SunPower to become the winner of the first annual Sustainability Award from pv magazine.
Cradle to cradle certified
The SunPower Maxeon Panels are the world's first solar panels to be Cradle to Cradle CertifiedTM, which makes SunPower the world’s leading manufacturer when it comes to sustainability.
See the full detail about the SunPower cradle to cradle certification here
SunPower Battery Systems
SunPower first entered the highly competitive energy storage market in late 2019 with the Equinox storage system, but in 2021, it was rebranded as SunVault Storage. The company recently released the SunPower Reserve battery energy storage system in Australia, the first all-in-one solar and battery energy storage system (BESS) developed by SunPower.
SunVault Storage
The SunVault Storage system is an AC-coupled battery that can be retrofitted to homes with an existing solar installation. However, unfortunately, SunPower has restricted the system, so it can only be installed in homes along with SunPower solar panels. This is a strange move, considering all other AC-coupled batteries, such as the Tesla Powerwall, can be used with any brand of solar panels. The SunVault system comprises a 13kWh or 19kWh battery together with the well-regarded Schnider Electric XW Pro off-grid inverter. The Schnider inverter is a high-performance (transformer-based) inverter capable of supplying 6.8kW of continuous power with an impressive 12kW surge rating, making the SunVault one of the most powerful AC-coupled battery systems.
The smaller Hub+ module is the brains of the system and houses the load centre and grid isolation equipment to enable off-grid operation in the event of a grid outage. This configuration is very similar to the well-known Tesla Powerwall 2. However, unlike Tesla, the SunVault uses safer lithium Ferro phosphate (LFP) cells which have become the chemistry of choice for stationary battery storage systems.
Sunpower SunVault Storage system features 13kWh of battery capacity and a 6.8kW continuous power rating.
Like the Tesla Powerwall 2 and Sonnen ECO battery systems, the SunVault system is AC-coupled. It is connected directly to the main switchboard (load centre) and can be retrofitted to homes with an existing solar system. Two or three SunVault systems can be connected in parallel for additional energy requirements, providing 26kWh, or 39kWh of usable storage capacity. The 13kWh SunVault system costs slightly more than the competition at US$16,000 plus installation.
Download the full SunPower SunVault Storage System brochure.
SunPower Reserve
The new SunPower Reserve, released in Australia, is a complete solar and battery solution. This means the solar panels are connected directly to the inbuilt hybrid inverter, unlike AC-coupled battery systems, which require a separate solar inverter. The inverter is rated at 5kW, with a surge power rating of 7.5kW for 30 seconds, higher than most competing 5kW hybrid single-phase inverters. The total battery capacity is 10.1kWh, and up to 6 battery modules can be connected in parallel for up to 60.5kWh of storage.
The hybrid inverter contains dual solar (MPPT) inputs with a wide operating voltage range from 100V to 550V, a high input current rating of 15A, and an Isc rating of 18.75A, making it compatible with the more powerful, high-current solar panels now available. The inverter and battery are both covered by a 10-year warranty. However, the battery is limited to 2.92MWh of energy throughput, meaning it cannot be discharged below 20% SOC (State of charge) on a daily basis. This is not uncommon for battery manufacturers, as a full discharge below 20% on a regular basis is known to reduce battery life. See the full SunPower Reserve warranty here. Being a very new battery system, we have limited real-world feedback from solar installers and users. However, considering SunPower generally only produces high-performance, reliable products, it can be assumed that the new Reserve battery system will meet these high expectations.
Download the full SunPower Reserve Specifications datasheet.
Conclusion
SunPower is widely regarded as a world-leading solar panel manufacturer, and very few companies can compete at the same level of performance and quality. The Gen 7 Maxeon series leads the world, once again, in terms of outright efficiency. Although the competition is closer than ever, it should be remembered that Maxeon panels have maintained the title of the most efficient panels with the lowest degradation and best performance warranty for well over a decade. Not surprisingly, the Maxeon panels are also the most expensive on the market. However, like most things, quality comes at a price. Considering that solar is a long-term investment, the higher price equates to better performance, improved reliability, and more energy generation over the system's life.
The financial issues faced by SunPower over recent years raised some concerns over the company’s ability to honour its long-term warranty commitments. Despite this, SunPower is generally ranked number one in the US and many parts of the world by installers and customers. In other markets like Asia and Australia, SunPower does not have the same presence, and the very high price of the Maxeon series can be difficult to justify when some other manufacturers offer similar performance and quality at a lower price. That being said, there is no other manufacturer that can match the new 40-year SunPower product and performance warranty.
The Performance series panels have also been very successful in the commercial solar sector, being very cost-effective and backed by one of the best warranties available. With the improving financial outlook and the next-generation Maxeon 5 and Maxeon 6 series (M-series) panels now available, it looks like SunPower may continue to be an industry leader for some time to come.
Solar Questions
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