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A Complete Review of LONGi Solar Panels

Solarkobo Score: 4.0/5

Manufacturer's Profile

LONGi solar panels are made by a wholly-owned subsidiary of the Chinese company, LONGi Group, LONGi Solar. Founded in 2000 as Xi'an Longi Silicon Materials Corporation, by 2017, it had been recognized by Bloomberg as a Tier One module manufacture company thus, making it the most financially secure and bankable solar manufacturing company in the world, a position it has retained ever since. By 2021, it had overtaken other Chinese brands, Suntech, Yingli, Trina and Jinko to become the largest solar panel manufacturer in the world, a position it also retains till date. LONGi is regarded as the world's fastest growing solar manufacturing company. It makes its solar panels in China, India, Vietnam and Malaysia with offices in Australia, USA, Brazil, China, Germany and Japan.

With a strong emphasis on research and development, LONGi Solar is arguably the most innovative solar panel manufacturer in the world. LONGi is well known for breaking world records in solar cell efficiency in quick succession. Between 2017 and 2018, it broke the world record three times in just five months. For much of last year, 2021, it held the world record for solar cell efficiency until September when Australian start-up SunDrive stole away the record with a solar cell with an efficiency of 25.54%.


The traditional technology used in the manufacture are the polycrystalline and monocrystalline technologies. Between the two, monocrystalline is the superior cell technology. They are more efficient though they cost more to manufacture. With the drop in manufacturing costs, many manufacturers now use more sophisticated variations of the monocrystalline technology. In fact, even though poly cells are still widely used and very reliable, the top brands have altogether stopped issuing polycrystalline panels and many mid-grade manufacturers are following suit.

LONGi Solar is known for pioneering the use of only value-based high-efficiency monocrystalline solar cells for its panels long before it became the trend. It has been credited as being responsible, in part, for moving the solar industry away from polycrystalline panels towards the more efficient monocrystalline solar technology.

Gallium Doping

LONGi solar panels have slower degradation rates than other brands. LONGi guarantees that their mono panels will degrade by just 0.55% per year and 0.45% per year for the bifacial modules. In comparison to the traditional degradation rate of 0.7%, this is significantly lower. For their latest module offerings, the Hi-MO3 and Hi-MO4 are warrantied to produce even more power, 1.85% more after 10 years and 3.35% more after 20 years.

LONGi achieves this by doping its silicon wafers with gallium instead of the commonly used boron. This technology was developed by LONGi Solar in collaboration with Shin-Etsu Chemical Co in early 2020. The goal is to reduce loses caused by trace amounts of leftover oxygen and to reduce loses due to light-induced degradation over the first year to 2% and less than 0.5% per year for the lifetime of the panel. In this way, the panel is able to retain close to 85% of the original power after a 30 year period.

Smart Soldering

Several manufacturers that now use the multi busbar (MBB) technology developed ways to reduce the gaps between cells in order to increase surface area and boost efficiency. By using a special proprietary triangular shaped MBB with flattened ends, LONGi Solar achieves a reduced inter cell space and higher efficiency of at least 0.3% higher than is achieved in solar panels made from the conventional MBB technology.

Source: LONGi

Range of LONGi Panel

LONGi offers half-cut and bifacial monocrystalline panels made with laser-grooved PERC cells. With extra enhancements, LONGi modules achieve up to 20.9% efficiency. LONGi is also a high-power panel pioneer. Most of LONGi panels are rated from 350W to 540W.

Half-Cut Mono Modules

In its Hi-MO 4, LONGi offers 60 and 72 half-cut solar panels and all-black solar panels with high output power ratings from 355W to 460W. Panels in this series are offered with residential installations in mind. They are also suited in mountainous regions and areas where handling modules can be difficult.

Bifacial Modules

In its Hi-MO 5 Series, it offers half-cut bifacial panels with even higher power ratings from 480W to 525W and efficiencies of up to 21%. LONGi offers its bifacial solar panels for commercial, industrial and large-scale installations. Hi-MO 5 panels are designed for ultra-large power plants.

All-Black Modules

In its Hi-MO X Series launched in 2019, LONGi also offers All-black, shingled, back-contact modules in the half-cut design and with high output power ratings. They have a sleek design that is aesthetically pleasing. They are fitted with a high-strength black frame making them one of the best looking solar panels on the market.

The Hi-MO N

In July 2021, LONGi launched its Hi-MO N module, a bifacial module manufactured with a next generation n-type TOPCon cells. It maintains LONGi’s optimal 182mm cell and 72-cell module size and adopts LONGi’s proprietary high performance cell (HPC) technique based on the n-type TOPCon. The conversion efficiency is up to 22.3% and output power ratings in mass production reaches 570W.

The Hi-MO N was designed for applications on surfaces with high reflections, high temperature, limited land and high labour costs.


LONGi solar panels come with an industry standard warranty of 10-year product and 25-year linear performance. At the end of the 25-year period, LONGi guarantees that its modules will still produce up to 83.8%. Though matching warranties offered by Trina Solar, Canadian Solar and other mid-range brands, it still falls short of the warranty of 25 year product and performance warranties offered by the premium brands, LG and Panasonic.

Learn More About How LONGi Modules Compare With Other Brands Here.

Alongside the counterpart Chinese brands, LONGi stands very close to the small circle of premium brands highly regarded for their high performance and sophisticated design: SunPower/Maxeon, Panasonic and LG. Like most most Chinese manufacturers working hard to drive down production costs, they are driven towards the mass rather than the premium market. However, LONGi does not lag behind the premium brands, it offers high performance panels at mid-range pricing. This makes them cost-effective options for users looking for the best performance at mid-level pricing.

SolarKobo helps businesses and homeowners in Lagos and throughout Nigeria make the best possible choice of solar panels, batteries, charge controllers and inverters. We also have university-trained engineers that provide the best installation on order. We are always happy and confident to recommend LONGi Solar panels to our clients.

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