South Africans making a big mistake when buying solar panels

South African households and businesses are primarily buying cheap solar panels that are likely to fail within 10–12 years.

That is according to M Solar Power managing director Mark Becker, who recently spoke to MyBroadband about the recommended specifications shoppers should check before buying a panel.

M Solar Power is a major distributor of PV solar panels and equipment, specialising in high-end hardware for commercial and residential installations.

Becker told MyBroadband that South Africans were effectively buying solar panel “duds”.

“We are an uneducated market buying the overruns from two years ago. A European consumer wouldn’t put up with the panels that we buy,” Becksar said.

One of the fundamental issues is that homes and businesses are buying panels with plastic (laminated) backsheets instead of glass.

These panels are a few hundred rands cheaper but come with some significant drawbacks — including a reduction in performance of up to 4.5% within the first year of operation, Becker said.

He likened a solar panel with a laminated backsheet to a short-lived shower curtain, while a glass-on-glass panel was the equivalent of fitting a proper shower door.

The problem with glass-on-plastic products is that they start delaminating over time due to intense heat exposure.

This delamination causes separation or peeling of the layers of protective material, perspex, glass, or the photovoltaic material itself.

“We are putting ‘shower curtains’ on our roofs at an average operating temperature of 80°C,” said Becker.

“The research has found that after the first 12–15 years of output on laminated panels, you are looking at an 80% failure rate.”

In addition to lasting longer than laminated panels, glass-on-glass models are less likely to catch fire in case of a wiring fault, as illustrated in the video below.

A glass-on-glass design is the most important checkbox for a long-lasting, high-performance panel.

Once you’ve ensured the panels you have your eyes on meet this requirement, there are four other key criteria to consider.

N-type panels

These panels’ solar cells are manufactured by mixing phosphorus with silicon, unlike traditional P-type panels that have silicon mixed with boron.

The advantage of phosphorus is that it has one more electron than silicon, making the solar cell negatively charged, while using boron results in a positively charged cell due to the element having one fewer electron than silicon.

When exposed to oxygen, boron can corrode the solar cell, resulting in lower efficiency.

Becker said N-type panels don’t have this weakness and boost efficiency from around 22% to 24.5%.

TOPCon (tunnel oxide passivated contact)

Becker explained that these panels pair a tunnelling oxide layer with a passivated emitter rear contact (PERC) solar cell, reducing recombination losses and increasing cell efficiency.

While regular PERC has a theoretical efficiency limit of roughly 25%, major manufacturers like Longi and JinkoSolar have achieved over 25% efficiency using n-type bifacial TOPCon cells.

This efficiency has gradually improved in subsequent testing.

Number of busbars

Busbars are the thin conductive copper strips that connect solar cells inside the panel.

With a higher number of busbars, more electrons can pass through the cells, resulting in power and efficiency boosts.

Becker said that the highest number of busbars First Energy offers on a solar panel was 19.

“In essence, they have almost double the electrons moving through the panels than typical panels,” Becker said.

Cell-lapping technology

The latest panels pack cells tightly together or on top of each other with no stingers between the cells.

“They’re picking up the contact by lapping them the way you’re touching the tile together,” Becker said.

By eliminating the spaces between cells, the panel makes more efficient use of its footprint.

Becker said unless the panels you are buying have these specs, you are buying three-year-old stock.

In addition, buying panels with these specifications means you are more likely to avoid fabricated panels.

“You won’t find fake panels on the market with these specifications. Only the biggest wholesale companies will have that in stock,” Becker said.

Avoid warranty hassles

Solar panel installers often punt a 10- or 12-year product warranty and 25-year theoretical output warranty.

Becker said the industry adopted the common 20-year or 25-year output warranty on a whim after one of the first major distribution players included it in their marketing.

In reality, if a customer does not get the output claimed under the warranties, the panel will have to go through an elaborate process to qualify for a replacement.

For example, if you contact your supplier and inform them your panel started delaminating, and it is still within its 20+ year warranty, they would visit your premises to take photos and submit them to the local distributor, who would contact the manufacturer.

The latter probably operates out of Germany, Canada or China, where the panel must be tested to confirm a manufacturing fault.

The warranty claim can then be denied for a wide variety of reasons.

“They will first try to tell you that the panels were not installed correctly, but if they can’t fault the installation, they will ask you to return the panel to them at your or the distributors’ cost so that they can assess the faulty unit,” First Energy explains on its website.

“Imagine the cost to do this and how much time it would take to process.”

“All of this can be avoided by following common sense and investing in a solar panel that has glass on both sides.”

AWPower managing director Christiaan Hattingh said getting consumers to buy into the pricier products was a challenge, despite their substantial benefits.

“We are trying to push the glass-on-glass panels, because we just have such a good experience with the products,” Hattingh said.