LONGi Solar - Solar Panel Reviews

About LONGi Solar

LONGi is the world's largest manufacturer of solar panels and has held this position for four years. In the solar industry, that's a Longi time. While they may not keep the number one spot, they are likely to be among the largest for years to come.

The Chinese company became a solar giant by producing panels with a good combination of affordability and reliability. Their panels come with 12, 15, or 25 year product warranties.  The ones most likely to go on Australian residential roofs have 25 year product warranties.

Because they're reliable and good value for money, LONGi panels are among those SolarQuotes recommends. I'd be fine with having them installed on my mother's roof. In fact, our blogger, Anthony, did put them on his mum's roof.

Company History

LONGi Solar was founded in 2000. It may be hard to believe, but the company wasn't named after Australian solar legend Jack "Longy" Long. Instead, it was named after Jiang Longji, a university president who died in 1966. The name choice makes it look like the young company was trying to curry favour with the Chinese government, but LONGi's founders insist it was just because he was a really cool dude.

Initially, LONGi produced silicon for electronics. In 2005, they began producing silicon for solar, and in 2006, they had enough capacity to make around 1,000 tonnes a year. They then began climbing their way up the solar supply chain, starting with cutting the silicon ingots they made into wafers used for solar cells. In 2014 they purchased a solar panel manufacturing company.  This completed their transformation into an enormous, vertically integrated company, involved in all major steps of solar panel production. They have continued expanding at a rapid rate and, in 2021, also moved into producing equipment for hydrogen production.

Production

In 2023 LONGi shipped a massive 67.5 gigawatts of solar panels. That's enough to generate electrical consumption equal to half of Australia's electricity consumption.  Not bad for a single company. 

All but 1.1GW of their solar panel production was exported.  This means 217GW of solar China installed in 2023 was mostly met by other manufacturers.  If the fact that China barely uses Longi panels is not a cause for concern, as China usually exports its higher quality products.

In 2023 Longi produced 125.4GW of monocrystalline solar cell wafers.  Again, pretty much all they didn't use themselves was sold to other countries.

Monosilicon Only

Two types of silicon are used to make solar cell -- polysilicon and monosilicon. LONGi only makes and uses monosilicon. While more expensive than polysilicon, its efficiency is higher and has been gradually gaining market share. Just about every panel going on an Australian roof these day is monosilicon.

Production Locations

LONGi's headquarters are in Xi'an, a city of 13 million that's famous for flatbread in lamb soup and terracotta dudes. It's located in Shaanxi province, which has goddamned beautiful mountains that often can't be seen because of goddamn awful air pollution. The bulk of LONGi's silicon production occurs in this province.

Most of LONGi's production is in China but they also have factories in Malaysia and Vietnam. For years now they've been talking about opening facilities in India, but that project has been really slow to get off the ground. They've also built a $900 plant in Ohio in the United States, that should be in operation now and able to produce up to 5 gigawatts of panels a year.

LONGi Hi-Mo X6 Panels

Any Longi panels you get now for residential solar will almost certainly be their Hi-Mo X6 panels.  There are three slightly different versions being sold in Australia.  Longi calls them Explorer, Scientist, and Guardian panels.  All have fairly high efficiency, positive power tolerance, and performance warranties that promise a low rate of degradation.

If you want to check out panel information on the Longi website, check the page is set to Australia, because they don't offer the same panels or the same warranties in every country.

Efficiency

Most panels going on roofs these days have efficiencies ranging from 20% to over 24%.  The Hi-Mo X6 panels offered in Australia range from 21.3% to 23.3%.  At this time, I'm happy to call any panel with over 22% efficiency a high efficiency panel.  All else equal, the higher the panel efficiency, the more energy they'll generate for a given amount of roofspace.

Heat Tolerance 

As solar panels get hotter, their output declines.  For typical modern panels it will drop by around 0.3% for every 1 degree Celsius the panel goes over 25 degrees.  The Longi Hi-Mo X6 panels available in Australia fall by 0.29%.  This means their heat tolerance, while not bade, isn't exceptional by today's standards.

Power Tolerance 

Longi Hi-Mo X6 panels have positive power tolerance, which means their output, when new, will always be at least equal to to their official rating, which can range from 415W to 626W.  For most Hi-Mo X6 panels the tolerance is give as +0-5W, but for some 0-3%.

Hail Resistance

Longi Hi-Mo X6 panels are certified to resist 25mm hail striking the panel at 23m/s without harm.  This level of resistance is standard and sufficient for them to survive impacts from normal sized hailstones

Shading Isn't Permitted

The installation manual states the panels cannot be shaded.  While Longi may allow exceptions in some situations, taken at face value, this rules out their use for many installations.

Right By The Beach Is Bad

Their installation manual says Longi panels can be installed 50m or more from the beach.  It also recommends anti-corrosion treatment wherever they may be exposed to sea mist. 

A 10° Tilt Is Recommended

While it's not a requirement, it is recommended the panels be installed at a tilt of at least 10° to allow rain to effectively clean them.

Performance Warranty

In Australia, Hi-Mo X6 panels have a 25 year performance warranty that promises their output will decline by no more than 1.5% in the first year and no more than 0.4% in each subsequent year.  This means they'll have at least 88.9% of their original capacity after 25 years.

Product Warranty

In Australia, Longi Hi-Mo X6 panels have a 25 year product warranty that protects against defects in materials and manufacture.  Longi refers to this as a 25 year warranty for materials and processing.

Making A Warranty Claim

The odds are good you'll never need to make a warranty claim on LONGi panels, particularly if you get ones with a 25 year product warranty. But if a problem does occur, the first person you should contact is the installer who provided them. If they're no longer around, you can contact LONGi Solar's Australian office directly:

LONGi Australia General Enquires: 02 8484 5805.

If you prefer to send an email, LONGi says they'll reply within 24 hours. Their email address is: [email protected].

100% Renewable Production By 2028

In 2020 LONGi committed to using 100% renewable energy by 2028. At that time their energy use was 42% renewable. In 2022 it was up to 47%. Obviously, they'll need to pick up the pace to hit the target, but with the amount of solar being installed in China, I have no trouble believing they'll meet their goal.

LONGi Hydrogen

LONGi has moved into producing equipment for hydrogen production, but only on a small scale at the moment. Their approach is to make electrolysers that have low efficiency but are cheap to make. This makes a lot of sense for a solar company working to ensure the world has plenty of low cost electricity during the day.

Financial Security

A long warranty isn't useful if the company it came from is no longer around to back it up. I expect a large company like LONGi will still be around well into the future, but it's not possible to be certain it won't disappear and render its warranties worthless.

The good news is there is plenty of evidence LONGi is currently financially secure -- or at least secure for a solar panel manufacturer. As of July 2023 they had been in PV-Tech's PV ModuleTech bankability report's highest category for three and a half years. This means they're one of the solar companies considered least likely to suffer bankruptcy or financial problems.

Unfortunately, it's always possible for a company's financial position to rapidly deteriorate. Many manufacturers are likely to face problems over the next couple of years thanks to falling panel prices. But I have a feeling LONGi will be around long-term. I don't have any specific evidence to back this up, it's just a feeling I have in my gut. Specifically, my longi-intestine.

A Recommendation

Because we consider them reliable and well-supported in Australia, SolarQuotes is happy to recommend using LONGi Solar panels. If you put them on your roof -- or your mum's roof -- you are very unlikely to need to make a warranty claim, especially if you use ones with a 25 year product warranty.