LONGi Solar Panels In Brief:
LONGi is the biggest solar panel maker in the world, using manufacturing plants in China, India, Vietnam and Malaysia. It puts significant resources into research and development, and has broken many world records for panel efficiency.
Unlike some other solar panel manufacturers, the company only makes monocrystalline panels. This technology is considered by experts to be superior, and the way forward for the solar PV Industry. High efficiency, slow degradation, high power output, mean that LONGi solar panels are among the best in the solar industry.
LONGi solar panels come with an industry standard warranty of 12-years on solar panel products and the power output warranty is 25 years. LONGi is considered a major “best buy” choice for homeowners who want to invest in a solar array, whether to reduce energy costs, embrace a greener lifestyle, or charge their EV.
LONGi Company Overview:
LONGi Solar was founded in 2000 as Xi’an LONGi Silicon Materials Corporation. It soon gained a reputation for superior solar PV products.
By 2017, financial media source Bloomberg named it as a Tier One module manufacture company which made LONGi the most financially secure and bankable solar manufacturing company in the world, a position it retains to date. It was also the fastest-growing and by 2021 had overtaken all other Chinese solar companies to become the largest photovoltaic panel manufacturer in the world.
LONGi employs some of the most advanced manufacturing capabilities in making its solar panels, so is consolidating its lead over its competitors. In 2023 its annual revenue reached £14.32 billion, so it is truly a giant among renewable energy manufacturing companies.
LONGi Solar Panel Specifications
LONGi offers three ranges of residential solar panels:
- LONGi Hi-MO 4 Series
- LONGi Hi-MO 5 Series
- LONGi Hi MO 6 Series
LONGi deploys innovative solar cell technologies to ensure that its solar offerings are among the best on the market. These include monocrystalline chips, gallium doping, closer panel alignment, low degradation and higher power output.
Why Monocrystalline Panels for LONGi?
Formerly solar panel manufacture was split between two technologies: polycrystalline and monocrystalline. Polycrystalline was a cheaper option, but monocrystalline solar panels are generally more efficient. LONGi does not make polycrystalline panels.
Now the majority of the high-end solar companies are concentrating on monocrystalline wafers. With manufacturing costs coming down, the price advantage that polycrystalline technology formerly traded on is being eroded. LONGi’s decision to concentrate only on the most efficient solar panels has proven to be the correct one for longer term market dominance.
Gallium Doping
In 2020 LONGi applied gallium doping to its new panels, instead of the previously used Boron technology which was prevalent with other brands. This technology was developed by LONGi Solar in collaboration with Shin-Etsu Chemical Company.
Power generation losses due to light induced degradation are a known issue for all solar panels: basically, they age, and produce lower amounts of electricity the older they get. The trick is to reduce these losses to a minimum.
LONGi solar panels lead the field with low degradation rates. The company guarantees that their monocrystalline panels will degrade by a mere 0.55% per year and 0.45% per year for the bifacial modules. The average industry degradation rate is 0.7% per year.
LONGi solar panels will outperform most others significantly during their lifespan. A LONGi solar panel will be delivering nearly 85% of the original power at the end of a 30-year term.
Smart Soldering Technology and Close Alignment Between Cells
If the cells that make up a solar panel can be aligned more closely and have multi-busbar (MBB) connections between them, electrical output will be raised. LONGi deploys its own proprietary smart soldering and MBB technology to achieve very close spacing between cells, with an efficiency of more than 0.3% over competitors using conventional MBB methods of panel construction.
Aesthetics
The three series each offer an “all black” option, rather than the conventional blue with aluminium frames that comprise most rooftop solar installations. Now customers have a choice of conventional-looking panels or perhaps a different aesthetic which might be more attractive for their roof array. The Hi-MO 6 series also offers an “Artist” collection of panels in different colours.
Hybrid Passivated Back Contact (HPBC) Cell Design
The ground-breaking new Hi-MO 6 series are the first panels ever to feature a Hybrid Passivated Back Contact (HPBC) cell design. This unique new cell design improves power output and is expected to become a market-leading technology.
Environmental Considerations
LONGi has long been in the forefront as a solar company with an environmentally-conscious manufacturing and supply chain. They have integrated many leading concepts into their supply chain management system, such as green design, green manufacturing, green construction, green recycling and reuse, and green product life-cycle management.
The company has been working with their suppliers, manufacturers, logistic solution providers, wholesalers, customers, and recycling partners to effectively reduce energy waste and pollutant emissions throughout the entire value chain and keep emissions down over the products’ complete life-cycle. LONGi panels are also packaged in a minimalist, eco-friendly manner to minimise waste.
Hi-MO 4 Series – Hi-MO 4 and Hi-MO 4M
The Hi-MO 4 series is one of the few types of solar panel which uses gallium-doped silicon cells which increases the solar panel’s resistance to degradation. This means the amount of power the panel will produce will remain higher because of a 0.55% per year degradation rate over a long period, than most other panels which have a typical annual degradation rate of 0.7%.
These solar panels also offer a 12-year product warranty which is in line with most of the options on the market. LONGi offers a long-term performance guarantee: at the end of 25-years the installed modules will still produce up to 84.8% power output.
The key difference in the M designation products is that they are specifically designed for residential rooftops, while the other solar panels are more oriented towards commercial and industrial solar arrays. Please note that this is just a convenient categorisation from LONGi depending on the roof area available.
Specifications
Hi-MO 4 series solar panel key parameters:
- Monocrystalline PERC gallium-doped silicon cells
- 350W to 380W Power rating
- 20.9% maximum panel efficiency
- Half-cut cell technology with 9 busbars (MBB)
- Standard 166mm M6 wafer
- 12-year product warranty
- 25-year performance warranty
- 84.8% remaining power after 25-years
Hi-MO 5 Series – Hi-MO 5 and Hi-MO 5M
The Hi-MO 5 series with a slightly improved solar panel efficiency can offer customers more power whilst only taking up the same amount of space on the roof.
LONGi have also increased the working current within the panels to around 13amps (from 11amps in the Hi-MO 4m series) which is better suited to the mainstream string inverters that are now on the solar market.
Hi-MO 5 series solar panel key parameters:
- Monocrystalline PERC gallium-doped silicon cells
- 475W to 540W Power rating
- 21.3% maximum panel efficiency
- Half-cut cell technology with 9 busbars and smart soldering
- Larger 182mm M10 wafer
- 12-year product warranty
- 30-year performance warranty
- 84.9% remaining power after 30-years
Hi-MO 6 Series
LONGi new generation HPBC cell technology is a step-change in the mass production of high-efficiency cells and continues to lead solar technology. The efficiency of LONGi HPBC cells is more than 25.0%. The efficiency of the PRO version is even better and its HPBC cells output is more than 25.3%.
This is one of the highest efficiencies currently available, and is superior to that of competitors’ products that are using N-type cells. The Hi-MO 6 series uses a new P-type Hybrid Passivated Back Contact (HPBC) cell design, giving superior performance in all kinds of conditions.
The Hi-MO 6 series panels are subdivided into four types: Explorer, Scientist, Guardian and Artist models, which offer a slightly-different flavour of advanced solar cells so the buyer can pick which suits their objectives most closely. Explorer is the basic HPBC panel design. Scientist offers maximum efficiency and low degradation. Guardian contains integrated smart panel-level optimisers. Finally, Artist offers panels in a selection of unique colours.
Hi-MO 6 Series Key Parameters:
- Monocrystalline HPBC cells
- 410W to 600W Power rating
- 2.8% maximum panel efficiency
- Half-cut cell configuration with HPBC cell technology (MBB)
- Large 182mm M10 wafer
- 15-year product warranty
- 25-year performance warranty
- 88.9% power remaining after 25 years
Pros and Cons
Pros
- Monocrystalline panels have more efficient cells and deliver more energy
- Low degradation over lifetime
- Top global manufacture
- Good value for money even though offering more than an affordable mid range panel
- Ecological packaging with low waste
Cons
- LONGi is introducing a new N-type next generation panel which may supersede the Hi MO 4-5 series
- LONGi does not have a UK office so the support comes from partners rather than directly from the manufacturer
- Guarantee is slightly inferior to the 25-year product and performance warranties offered by the premium solar manufacturers such as Panasonic and LG
LONGi Solar Panel FAQs
What roof types are LONGi solar modules suitable for?
LONGi modules are suitable for most roof types (flat/pitched roof, steel, tile, etc.). Your installation company will perform a roof survey, assessment of the roof structure and design an appropriate PV system for your particular roof.
How does LONGi ensure its solar panel systems can maintain sustained high energy yields for 25 years?
The use of a high-efficiency monocrystalline PERC cell made of M6 gallium-doped silicon wafers and the selection of more reliable double-glazed module packaging ensures that the 30-year power degradation of the modules is not greater than 15%. The special cooling air duct design alleviates the loss of energy yield due to structure cooling.
What is the payback time on LONGi Solar Panel products?
The payback period varies, depending on the roofing orientation, installation position, local weather and sunlight availability, as well as utility tariffs. An industry rule of thumb is that payback time with solar power and solar panel installations is typically around eight to eleven years in the UK currently, but this is just an estimate and will vary with your particular situation.
LONGi Solar Panel Review Summary
LONGi are the leading solar panel manufacturer in the world. Their offering must be amongst the best for efficiency, resistance to degradation, power output and value-for-money. While LONGi solar panels cost more than budget solar panels, most householders would want to put them on their shortlist when looking at which cost effective solar panels they would want to pair up with their solar system.
