LONGi Hi-MO 5: The Award-Winning Solar Panel Series by LONGi

The LONGi Hi-MO 5 series is one of the best solar solutions designed and manufactured by LONGi, specially created for utility-scale applications, but adaptable to residential and commercial ones. These modules feature cutting-edge photovoltaic (PV) technology embedded in high-quality solar cells, making LONGi the winner of the Intersolar award in the photovoltaic category in 2021.

If you want to learn more about the LONGi Hi-MO 5 series, you will find everything you need in this article.

Here we will review in detail every aspect of the technology used to create the LONGi Hi-MO 5 series, going from the design of the solar cell, the durability, the efficiency, and the performance, up to the warranty for the product and its performance, covering each module in this series.

100MW Qinghai PV Power Station With LONGi Hi-MO 5 Solar Panels
Photo: LONGi

LONGi Hi-MO 5: The award-winning PV module by LONGi

The LONGi Hi-MO 5 is one of the most groundbreaking PV modules designed by this company. This solar panel series is manufactured using technological improvements like bifacial, PERC, and half-cut solar cell technology embedded in high-quality monocrystalline silicon (mono c-Si) wafers.

To ensure that LONGi Hi-MO 5 solar panels withstand the most challenging environment and deliver the best performance, they feature superior protective technology and are tested in different operating conditions. The efficiency was also obtained by testing them to the Standard Test Conditions (STC) and Nominal Operating Cell Temperature (NOCT) conditions.

There are five different PV modules in the LONGi Hi-MO 5 series, varying in nominal power rate from 530 W up to 550 W. The LONGi Hi-MO 5 series feature high efficiency, robust design, and outstanding performance that is destined for utility-scale applications, but these modules can easily be repurposed for commercial and residential applications in the right terrain.

In-depth review of the LONGi Hi-MO 5 series

To appreciate the technology and benefits of the LONGi Hi-MO 5 series, it is important to understand how they work. In this section, we will be reviewing in detail the design, durability, efficiency, performance, and warranty for these modules.  


Four highly important design characteristics result in outstanding quality for each LONGi Hi-MO 5 PV module. These are the type and size of the monocrystalline silicon wafer used to manufacture the module, the half-cut cell design, the PERC technology, and the bifacial technology.

Monocrystalline M10 wafer technology

The first and most important feature of the LONGi Hi-MO 5 solar panel series is the technology used to manufacture solar cells. Each solar cell in this series features high-quality P-type monocrystalline silicon wafers doped with gallium, this technology has proven to be cost-efficient, stable, and better for the efficiency of the module.

On top of the high-quality monocrystalline solar cells, the LONGi Hi-MO 5 PV module series implements the M10 standard wafer size. This standard increases the size of each uncut solar cell to 182 mm, being one of the most suitable options for utility-scale applications that require modules with a larger size.

Half-cut cell manufacturing

LONGi Hi-MO 5 Half-Cut Cell Design

The second most important design implementation for the LONGi Hi-MO 5 series is the half-cut cell technology used at the moment of manufacturing the modules. Implementing this technology has delivered outstanding results for PV modules, increasing efficiency by significantly reducing power losses caused by Joule’s law due to higher currents being conducted at the busbars.

Half-cut solar cell technology consists of cutting each M10 solar cell in half to around 91 mm x 182 mm for the LONGi Hi-MO 5, installing twice as many half-cut cells on each side of the module. This means that instead of featuring 72 full-size solar cells, the LONGi Hi-MO 5 modules feature 144 half-cut solar cells over the whole module, conducting the electricity thanks to the implementation of 9 smart soldered busbars per cell.


LONGi Hi-MO 5 solar panel series implements bifacial technology, which can be extremely useful in utility-scale applications that are more suited to take advantage of the albedo resource, which is the solar radiation reflected on the ground around and below the modules. This is achieved by exposing both faces of the solar cell to radiation, increasing energy production by as much as 30%.

To protect the backside of the solar cell, the LONGi Hi-MO PV module series include a 2 mm anti-reflective superstrate and a 2 mm tempered glass substrate. This way the modules are exposed to solar radiation on the back, but still are protected against external agents.


The last technology implemented onto the LONGi Hi-MO 5 solar cell is the Passivated Emitter and Rear Cell (PERC) technology. PERC technology slightly restructures the architecture of the solar cell by adding a reflective layer at the back side of it; this reflects unabsorbed solar radiation, increasing the opportunity to absorb it and turn it into energy.

PERC technology is cost-efficient, while still delivering notorious improvements in the efficiency of the solar cell. PV modules featuring this technology like the LONGi Hi-MO 5 PV module series can produce 6% to 12% more energy than traditional modules.


LONGi Hi-MO 5 solar panel series are rated for utility-scale applications, featuring a highly robust design with quality encapsulation. In this section, we explain the encapsulation technology used on these modules and the results of the tested durability.

Encapsulation technology

LONGi Hi-MO 5 Dynamic Loading Testing
LONGi Hi-MO 5 Dynamic Loading Testing | Source: ET Energy World

Utility-scale PV modules can be exposed to all types of external agents depending on the location of the modules. This highlights the vital role of encapsulation technology for the LONGi Hi-MO 5 solar panel series since they are designed for these harsh external applications.

The encapsulation technology for each LONGi Hi-MO 5 solar panel includes dual glass protection. The first one is 2.0 mm anti-reflective glass and the second one is 2.0 mm heat-resistant tempered glass. Each PV module is protected by an anodized aluminum alloy frame, achieving an Ingress Protection (IP) rating of IP68.

Tested durability

To ensure the LONGi Hi-MO 5 PV module is rated for utility-scale applications, these modules have been tested under the most demanding conditions. According to the IEC 61215, the LONGi Hi-MO 5 series withstands a mechanical load of 5,200 Pa on the front side, 2,400 Pa on the back side, and up to 25 mm hailstones at a speed of 23m/s, thanks to its Class II protection.

The LONGi Hi-MO 5 solar panel series is also compliant with the IEC 61730, IEC 62941, and UL 61730 certifications. The modules also include an IEC Class C fire resistance under the UL Type 29 certification. Additionally, the LONGi Hi-MO 5 PV modules are resilient against LID as a result of the implementation of gallium for the P-type doping.


Thanks to the implementation of cutting-edge PV technology, LONGi achieved an astonishing efficiency for the LONGi Hi-MO 5. In this section, we analyze the efficiency of these modules in STC, the temperature coefficient, and the power output in NOCT.

Optimal efficiency at STC

Standard Test Conditions (STC) measure the efficiency of PV modules at a temperature of 25°C and an irradiance of 1,000 watts per square meter (W/m2). Testing the LONGi Hi-MO 5 PV module series at this temperature and irradiance conditions results in an efficiency range of 20.7% up to 21.5%.

Power output in NOCT

The Nominal Operating Cell Temperature (NOCT) is another test measuring the efficiency of PV modules at more realistic irradiance and temperature conditions. This test places the modules at an irradiance of 800 W/m2, temperature of 20°C, and wind velocity of 1m/s.

Testing the performance of the LONGi Hi-MO 5 solar panel series at NOCT conditions delivered a power output range of 369.2 W for the 530W module, and up to 411.1 W for the 550W module. The efficiency range remained the same at 20.7% up to 21.5%.

Temperature coefficient

Another important metric used to determine and evaluate the efficiency of the LONGi Hi-MO 5 series is the temperature coefficient. When the solar panels in the LONGi Hi-MO 5 series were tested at STC and the temperature was modified, it resulted in a temperature coefficient of -0.34%/°C. This means an efficiency variation of -0.34% per each Celsius degree increase in temperature.


To review the performance of the LONGi Hi-MO 5 series, it is important to understand the power output for the different modules and their operating conditions. Analyzing the power degradation over time is another vital performance aspect to consider.

Power output and operating conditions

There are five modules in the LONGi Hi-MO 5 series with an efficiency range that goes from 20.7% up to 21.5%. The power output for all these modules increases in 5 W steps as follows: 530 W, 535 W, 540 W, 545 W, and 550 W. These modules operate in a temperature range of -40°C up to 85°C; however, it is important to remember that the efficiency is affected by the temperature coefficient.

Low power degradation over time

One of the best features of the LONGi Hi-MO 5 solar panel series is its linear power degradation over time, yielding an excellent energy output during its lifespan. It is expected that the modules in this series will lose 2% of their efficiency after the first year, and 0.45% per year after that for as long as 30 years after the module was installed.

At the end of their lifespan (around 30 years), the LONGi Hi-MO 5 solar panels will still deliver 84.95% of their designed power output. This is much more than the average expected for PV modules, as you will learn in the next section.


LONGi is extremely sure of the performance of its modules, which is why they cover their LONGi Hi-MO 5 solar panel series with a far-from-modest warranty.

Warranty for materials & processing

The warranty of the LONGi Hi- MO 5 solar panel series covers the workmanship of the modules for 12 years for the materials and processing during the manufacturing process. This aligns with the average warranty issued for most PV modules in the solar industry.

Warranty for extra linear power output

LONGi is extremely confident in the performance of its LONGi Hi-MO 5 solar panel series, which is why they cover them with an industry-leading warranty of 30 years for a power output of 84.95%. This warranty covers the modules 5 more years than the industry average and for higher power output since most warranties cover the modules for 80% at 25 years.

Final Word: LONGi Hi-MO 5, one of the best PV modules in the market

The LONGi Hi-MO 5 solar panel series is an extremely efficient, high-performing, and durable option available for utility-scale applications. These PV modules feature cutting-edge technology that improves performance, reduces degradation, and takes advantage of the albedo resource with its bifacial technology, making them excellent for ponds, snowy Alps, and other reflecting landscapes.

These PV modules are already being used in remarkable renewable energy power plants. Some of the largest and most notorious ones include the Guizhou Complex Mountain PV Power Station with a 150 MW capacity, the Shanghai Metro Solar Traffic Project with a 7.40 MW capacity, and the Floating Fishery PV Power Station with a 112.00 MW capacity.


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