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We take a good look at the Longi Hi-Mo 4’s efficiencies, performance and cost as we review the best solar panels in the UK.
The average home can save more than £1,000 every year with solar panels!
Known for their high efficiency and durability, Longi Solar’s Hi-MO 4 panels are among some of the best solar panels available. They utilise monocrystalline cell technology and achieve up to 20.9% efficiency, offering excellent performance. Available in several formats, the panels feature reduced light-induced degradation and have an annual degradation rate of just 0.45%. This means they retain 87%-89% of their power after 25 years, which is comparable to many premium models.
With a power rating of 350W-380W, a 12-year product warranty and a 25-year performance warranty, Longi Hi-MO 4 panels offer exceptional value, easily competing with more expensive options in the market.
The Longi HiMo series utilises high-efficiency PERC cell technology in both half-cut cells and bifacial modules. The HiMo 4-range modules are available in 60-cell, 66-cell and 72-cell formats, built on gallium-doped silicon in order to increase performance and reduce the degradation of cells from 0.7% to 0.45% per annum. This means that your Longi HiMo4 will only lose 11%-13% power after 25 years, which is comparable to more expensive N-type solar panels.
Highlights: Uses monocrystalline PERC gallium-doped silicon cells which are a good cost-effective alternative to more expensive N-cell solar panels.
Key benefit: 84.8% remaining power after 25 years, comparable to more expensive panels.
Warranty: There is a 12-year product guarantee as well as a 25-year performance guarantee available.
Cost: £100-£165 per panel, excluding the cost of installation and labour.
While the Longi HiMo4 isn’t the most expensive solar panel on the market, any investment in solar panels is quite significant for the average homeowner. It’s important to weigh the pros and cons carefully.
The benefits of the Longi HiMo4 include:
There are a few disadvantages to consider:
Longi Solar, together with Shin-Etsu Chemical Co, started mass-producing new gallium-doped silicon cells in 2020 to combat the effects of light-induced degradation in P-type PERC silicon solar panels.
This form of light-induced degradation causes a 2-3% loss of power within the first few hundred hours of operation as oxygen is left over from the manufacturing process. Over the remaining life of the panel, losses drop depending on the quality of the crystalline silicon.
Many solar panel manufacturers use boron-doped P-type silicon wafers, which are less stable and more prone to light-induced degradation. Gallium-doped silicon reduces the damage significantly, retaining close to 85% of the original power rating after 25 years of use.
Longi Solar also uses “smart soldering technology”, using a triangular shaped micro busbar flattened at both ends. This reduces the inter-cell gap, increases the surface area and boosts efficiency.
The triangular segmented ribbon maximises the absorption of sunlight and boosts efficiency by 0.3%.
Longi doesn’t sell specific add-ons for the HiMo4, but several compatible add-ons can be purchased via your solar panel installer. Longi HiMo4’s standard solar kit comes with solar panels, micro inverters with monitoring tools and accessories, and racking materials.
Longi offers the Hi-MO 5m panel, which is even more affordable than the Hi-MO 4 model and has higher efficiency rates. It employs the same monocrystalline PERC, gallium-doped silicon cells to reduce panel degradation and has Longi’s smart soldering technology to boost efficiency, making it a great alternative to the Hi-MO 4 panel.
This table compares Longi HiMo4’s solar panel to some others on the market.
| Solar panel brand | Efficiency | Solar panel output | Product warranty | Performance warranty |
|---|---|---|---|---|
| Longi HiMo4 | 19.5%-21.0% | 350W-580W | 12 years | 25 years |
| Longi Hi-MO 5m | 20.7%-21.8% | 405W-425W | 12 years | 25 years |
| JA Solar JAM60S4 LR | 22.7% | 530W | 12 years | 30 years |
| Jinko Solar Tiger Neo 66HL4M-(V) | 23.5% | 635W | 12 years | 30 years |
| Project Solar Evo Maxima | 22.7% | 490W | Lifetime | Lifetime |
JA Solar’s JAM60S4 LR solar panel is quite similar to Longi HiMo4. Both panels offer a 12-year product warranty and a 25-year performance warranty. However, Longi HiMo4 solar panels are less expensive than JA Solar’s Jam60S20, and with similar features this is something to consider when choosing the right solar panels for your home.
Compared to Project Solar Evo Maxima with a lifetime warranty, Longi HiMo4 falls short. However, the Longi HiMo4’s panel output range makes it a good choice of panel, especially if your household’s electricity consumption is high.
While the Longi HiMo4 is one of the most affordable solar panels on the market, its performance is on par with some of the more expensive modules in the UK.
| Name | Output | Cost per panel |
|---|---|---|
| Longi HiMo4 | 350W-580W | From £107.40 |
| Trina Solar TSM-DE06X | 365W | From £208 |
| Panasonic HIT N 245W | 245W | From £250 |
| Project Solar Evo Maxima | 490W | Around £350 |
| JA Solar JAM60S4 LR | 530W | From £100 |
The Longi HiMo4 doesn’t require a lot of maintenance. Regular rainfall should be more than adequate for keeping the solar panels clean. However, if you notice soiling or debris blocking the solar panels, you should rinse them from the ground with a regular garden hose.
If you cannot reach the solar panels with a hose, you can wipe the surface with a soft sponge or cloth and water. Do not use soap or chemical cleaning agents, and take care when climbing on the roof.
If performance doesn’t improve after cleaning, get in touch with a professional Longi technician.
Longi solar panels have a lifespan of around 30 years and maintain at least 84% of their original efficiency after 25 years. This makes them a durable and reliable choice for long-term solar energy generation.
Yes, Longi solar panels are considered Bloomberg Tier 1, which indicates that they are produced by a financially stable, reputable manufacturer with a proven track record in the solar industry.
A solar battery can prevent waste by storing any surplus energy your Longi panels produce. Although batteries can be expensive – ranging from £1,200 to £6,000 – their prices are decreasing, and they offer a faster return on investment due to high energy costs.
It used to take far longer to break even from solar panels investments, but high energy bills, cheaper installations and increased panel efficiency have shortened this time to an average of seven years.
Read our articles Are solar panels worth it – how solar panels pay back and Selling energy to the National Grid to find out more.
When compiling this review, we read and analysed over 500 customer reviews as well as dozens of reports and reviews by solar panels UK experts and installers. We used a scoring system to evaluate the Longi Hi-Mo 4 solar panels, scoring against the criteria that most homeowners would consider when making a solar panel purchase.
The score sheet evaluated the following:
Each solar panel or manufacturer received a total score out of 100.
For more information, read our article on how we review solar panels.
