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SunPower Solar Panels

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Introduction

SunPower are the best high performance solar panels on the market, offering up to 35% increase in lifetime generation from the same roof space and the best warranty on the market.

If you've done even the slightest bit of research on solar panels, the chances are you've come across the name SunPower. Founded in Silicon Valley, SunPower came to dominate the residential solar industry with its premium high efficiency panel offering. In 2020, Maxeon Solar Technologies was spun off from US-based SunPower Corporation as an independent company that sells SunPower panels internationally. But what makes the SunPower brand so special, if indeed it is?

SunPower: relentless innovation

The principal factor behind SunPower's success is its leading solar cell technology. SunPower solar cell efficiency is the best on the market.

Maxeon produces a range of high efficiency solar panels with efficiencies of up to 22.7% thanks to their patented back-contact cell design which maximises usable collection area (see below). On top of market-leading efficiency, SunPower panels also come with the best warranty on the market, both in terms of defects and performance.

SunPower panel range

Maxeon effectively offers two ranges of panels: SunPower Maxeon and Performance.

 

Output per panel

Size

W/m2

Maxeon 3 (residential)

355W-430W

1,690-1,812mm x 1,046mm

201W-226W

Maxeon 5 (commercial)

430W-450W

1,999mm x 1,016mm

212W-222W

Performance Residential

370W-390W

1,690mm x 1,160mm

189W-199W

Performance Commercial

405W-420W

2,066mm x 998mm

196W-204W

For comparison: standard monocrystalline

380W

1,776mm x 1,052mm

203W

SunPower Maxeon

Sunpower Maxeon 3 White Sunpower Maxeon 3 black
Maxeon 3 - White Maxeon 3 - Black

SunPower Maxeon is the absolute premium product, with the highest efficiency of any panel on the market. The commercial panels are a larger format to reach a higher output.

The all-black versions are slightly less efficient (because the darker colour increases module temperature), and so cover the lower output range.

Maxeon has also released an AC solar panel version, the SunPower Maxeon 5, which includes integrated micro-inverters.

SunPower Performance

SunPower Black Performance SunPower Performance Commercial panel
Performance Residential Performance Commercial 

SunPower Performance is a slightly lower efficiency (and less expensive product), similar to other monocrystalline panels in cost and performance. They use monocrystalline PERC cells, rather than the back contact technology in Maxeon panels. Again there are two ranges, one for Residential and one for Commercial. The Residential and Commercial panels have similar efficiencies (similar output per square metre) but the Commercial panels are physically bigger, and hence output more per panel.

SunPower: cell technology

SunPower Corporation has spent over US$450million on R&D in the last 10 years; it is thus unsurprising that the company holds more than 750 patents. The underlying technology that gives rise to SunPower's superior panel performance is its patented Maxeon solar cell.

Maxeon Solar Cell

These solar cells differ from conventional cells in that they utilise back-contact technology, which means no current collecting wires ('fingers' and 'busbars') on the top surface of the cells. Maxeon cells instead employ solid copper backing sheets to provide both the positive and negative electrical connections at the rear of the cell. As a result, the top surface area is maximised for better absorption of sunlight. 

The copper foundation also offers durability advantages over the porous metal paste used for front and back contacts in conventional cells. Maxeon cells are less susceptible to cracking and corrosion - the two main causes of cell degradation. 

Sunpower cell technology

Superior performance: up to 35% higher lifetime output from the same space

The higher solar cell efficiency of SunPower equates to more output per square metre. So for example, the top performing Maxeon 3 430W panel has a peak output of 430W out of an area of 1.90m2 - that's 227W per square metre. Standard panels typically generate 168W per square metre. So SunPower enables you to install a 35% bigger system in a given roof space.

In addition, the output from SunPower solar panels degrades at a much lower rate (around 0.25% per annum for Maxeon and 0.5% for Performance, instead of the standard 0.70% degradation). Furthermore the panels exhibit superior performance in hot rooftop conditions, and in partial shade.

For example, the temperature coefficient (reduction in power output at cell operating temperatures above the ‘standard’ operating temperature – usually 45°C) is -0.27% for SunPower Maxeon panels, compared to -0.39% for a standard polycrystalline panel, and -0.34% for the SunPower Performance range. So with a 10°C increase in operating temperature, output will drop 2.7% with Maxeon and 3.9% with standard panels. These seemingly small differences add up over many years.

Overall SunPower claims that a Maxeon 3 panel will produce as much as 35% more energy over the life from a given space than a similar rated standard panel. Just under half of this is due to reduced degradation and better 'real-world' performance, the rest is down to higher efficiency.

This ‘output premium’ is lower for other panels (see datasheets).

SunPower manufacturing

SunPower cells are manufactured in the Philippines. The modules are assembled in Mexico. The company is dedicated to making the most sustainable solar panels - the Maxeon 3 was the first to be Cradle-to-Cradle Certified.

Maxeon includes the following as standard in the build of its modules, improving reliability and thus facilitating the superior warranty:

  • the SunPower panel frames use adhesives from the aerospace industry to connect to the solar laminates, and are thus designed to withstand cyclonic wind loads;
  • the cells use high grade n-type monocrystalline with minimal impurities;
  • exceptional resistance to moisture and electrical stresses provides superior reliability;
  • tin corrosion barrier: the copper foundation is plated with tin to make it nearly impervious to corrosion;
  • the SunPower panels use triple redundant cell interconnections use built-in strain relief, thus allowing for expansion and contraction from daily temperature swings;
  • anti-reflective glass with high levels of quality control ensures a uniform glass layer maximising production on cloudy days.

Superior warranty

The industry standard for solar panels is a 10 year product warranty covering manufacturing defects, along with a performance guarantee that the panels will generate at least 80% of their initial output to 25 years. There is inevitably conflict over the boundary between these two warranties: the 25 year output potentially depends on the panels not having any manufacturing defects - thus there is a lack of clarity in the value of the standard power warranty alone beyond the 10 year coverage of the product warranty. Further there is generally no full service warranty, covering the removal, installation and transportation costs of a failed panel. 

Maxeon offers a superior warranty for a number of reasons, summarised in this table:

Product

SunPower Maxeon

SunPower Performance

‘Standard’ solar panel

Panel (defects)

40 Years

25 Years

10 Years

Output:

 

 

 

Year 0

98%

97.5%

97%

Annual decline

0.25%

0.5%

0.7%

Year 25

92%

85.5%

80.2%

Year 40

88.3%

n/a

n/a

Service:

 

 

 

Shipping – old panel

Yes

Yes

Possible

Shipping – new panel

Yes

Yes

Possible

Installation – new panel*

Yes

Yes

No

*Maxeon will pay for reasonable, necessary and actual removal and reinstallation costs of the repaired or replaced PV module up to £225 for up to 5 PV modules, and £45 per PV module thereafter for a single claim.

Maxeon extends the defects cover over 25 years and guarantees that its panels will output 92% of their original output at the 25-year mark, rather than the 80% of the standard panel. This implies a 7% lifetime output advantage over a standard panel per watt, however, as above Maxeon actually claims that their panels can produce over 20% more energy per rated Watt over 25 years.

For SunPower Maxeon panels, the warranty can be upgraded to a groundbreaking 40 years for product, performance and service by registering the installation. In this case, Maxeon guarantees 88.3% output after 40 years, an incredible vote of confidence in the durability of these products.

Furthermore, in the seemingly improbable event that one of its panels does develop a fault at any point over the 25/40 years... Maxeon will cover the complete cost of removal, replacement or repair, and reinstallation, as well as transportation costs for the return of defective panels and shipment costs for repaired or replaced panels (subject to the restrictions above).

This supreme confidence in the quality of their products distinguishes Maxeon above all other manufacturers operating in the PV industry.

Warranted panel power comparison

Premium products, premium price...

SunPower panels really do represent the best quality technology on the market, but unsurprisingly this comes at a price. That said, the Performance range is similarly priced to other high efficiency monocrystalline panels, but still benefits from SunPower's 25 year warranty.

By way of example, the Maxeon 3 panel will add approximately 30% to the cost of a typical small scale installation using a standard monocrystalline panel. SunPower claims that over the lifetime it will add around 35% to the output relative to that of a similarly rated system, so for this to make sense you also have to want the better aesthetics and the better warranty.

The panels definitely come into their own when space is limited, as they represent the best way to squeeze the last bit of power out of a given space.  

The Performance panels are much more comparable to a standard monocrystalline panel, but are generally more attractive when you consider the improved lifetime performance, reduced degradation and superior warranty.

So should you go for it?

If you can afford the additional upfront cost, we absolutely recommend you go for SunPower panels. If roof space is a limiting factor, as it often is, you will win on two counts versus a standard panel:

  • SunPower will enable you to get more out of your roof space, increasing the rated system output by up to 35%;
  • the SunPower system will exhibit superior lifetime performance, generating as much as 20% more power due to better real world performance than a similarly rated standard system.

You will also benefit from the superior warranty cover, and you'll be making a top aesthetic choice.

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Product brochures

Discover the range of SunPower solar panels: