quality solar panels
With hundreds of different solar panels on the market it is difficult for those not in the industry to identify quality panels which will perform over the expected 25 year life of a solar photovoltaic (PV) system. Here we highlight the best quality solar panel manufacturers using the latest solar cell innovations to develop the most efficient and reliable panels with the longest life and highest power output.
What is a Tier 1 Solar Panel?
A common term that sales companies and manufacturers use is the 'Tier 1' rating. The Tier rating was developed by Bloomberg New Energy Finance Corporation and is basically used to rate solar panel manufacturers in terms of financial stability. Unfortunately a Tier 1 ranking does not mean a panel offers the highest performance or quality. With most established panel manufacturers now rated as Tier 1, it is more important than ever to know how to distinguish a high quality and reliable panel by other means which we explain in more detail in our solar panel quality review.
Top 10 Solar panels 2021
Based on our international rankings, below is our list of the best residential solar panel manufacturers rated according to quality, reliability, performance, warranty and service, along with feedback from solar industry professionals. See our detailed solar panel quality review here.
|Make||Leading Model *||Cell type *||Max Efficiency *||Product Warranty **|
|1||LG Energy||Neon R||N-type IBC||22.0%||25 yr|
|2||Sunpower||Maxeon 3||N-type IBC||22.6%||25 yr|
|3||REC||Alpha||N-type HJT MBB||21.7%||20 yr|
|4||Panasonic||EverVolt||N-type HJT MBB||21.2%||25 yr|
|5||Solaria||Power XT||P-type Half-cut MBB||20.5%||25 yr|
|6||Qcells||QPeak DUO G9||P-type Half-cut MBB||20.6%||25 yr|
|7||Trina Solar||Vertex S||P-type Half-cut MBB||21.1%||12 yr|
|8||Winaico||WST-375MG||P-type Half-cut MBB||20.6%||25 yr|
|9||JinkoSolar||Tiger Pro N-type||N-type Half-cut MBB||20.7%||15 yr|
|10||Canadian Solar||HiKu6||N-type Half-cut MBB||20.8%||12 yr|
* Leading model using the most efficient cells currently offered by manufacturer
** Maximum product warranty period - May vary by country or region
Latest update - March 2021
Have your say - Professional feedback
In addition to continuous feedback from our solar specialists in Australia, the US and around the world, the clean energy reviews team invite all solar industry professionals and installers to give your feedback (positive or negative) from experience with any solar modules or manufacturers.
Latest Solar PV Cell Technology
Here we highlight many of the latest solar panel and PV cell technologies offered by the leading manufacturers. Plus we list some of the more popular panels available on the market using these innovative features.
Most panel manufacturers offer a range of models including mono and poly crystalline (also known as multicrystalline) varieties with various power ratings and warranty conditions. Solar panel efficiency has increased substantially over the last few years due to many advances in PV cell technology including:
PERC - Passivated Emitter Rear Cell
Bifacial - Dual sided panels and cells
Multi Busbar - Multi ribbon and wire busbars
Split cells - half-cut and 1/3 cut cells
Shingled Cells - Overlapping cells
High-density Cells - Removing inter-cell gaps
IBC - Interdigitated Back Contact cells
HJT - Heterojunction cells
These innovations and more explained in detail below offer various efficiency improvements, shade tolerance and increased reliability, with many manufacturers offering up to 25 year product warranties, and 25-30 year performance warranties. However, with all the new panel varieties available it is worth doing some research before you invest in a solar installation. In our complete solar panel review article we explain how to select a reliable solar panel and further highlight the best quality manufacturers on the market.
Solar panel efficiency
Solar panel efficiency is one of several important factors and is dependent upon both the PV cell type and panel configuration. Average panel efficiency has increased considerably over recent years from around 15% to above 20% as manufacturers incorporate the latest solar cell technologies and innovations. See more details about the many techniques used to increase efficiency in our detailed review of the most efficient solar panels available.
Most Efficient solar panels
At present, the world's most efficient solar panels are manufactured using IBC N-type monocrystalline silicon cells and achieve efficiency levels above 22%. The downside is IBC N-type cells are by far most expensive to manufacture, although the higher upfront cost is often outweighed by the increased efficiency, improved performance at higher temperatures and minimal light-induced degradation (LID), which means much higher energy yield over the life of the panel. Sunpower and LG Energy are the two leading manufacturers who use N-type IBC cells, however, the latest panels from REC and Panasonic utilise N-type heterojunction (HJT) cells which are very efficient and have an extremely low power temperature co-efficient which means they would outperform N-type IBC cells under certain conditions.
SunPower - Maxeon 3 - 22.6% efficiency
LG energy - Neon R - 22.0% efficiency
REC Group - Alpha - 21.7% efficiency
Panasonic - Evervolt - 21.2% efficiency
The complete list of the most efficient solar panels in 2021.
The industry leading performance warranty is offered on the Maxeon 5 and 5 series panels of up to 92%. The LG Neon R and Neon 2 panels are also covered by a 25 year product warranty and a new minimum 90 to 90.8% performance warranty after 25 years.
Poly Vs Mono Vs Cast-Mono Cells
Polycrystalline cells, often referred to as multicrystalline or 'multi' cells, are usually made from cast square ingots grown from multifaceted crystalline material (grown in multiple directions). These are cheaper to produce but offer slightly lower efficiency due to the recombination loss which occurs at the grain boundaries. Poly cells are still widely used and very reliable, but as explained below, monocrystalline cells are considered superior due to the higher efficiency and lower temperature coefficient.
Cast mono cells
Cast mono cells also known as Quasi monosilicon cells are made using a cast manufacturing process similar to polycrystalline cells. The less energy intensive casting process reduces the cost of manufacturing the ‘mono like’ cells compared to conventional mono cells made using the common Czochralski process. Cast-mono wafers are less susceptible boron-oxygen defects and have a low rate of light-induced degradation (LID) making them comparable in performance and reliability to monocrystalline cells. Cast mono cells have been around for many years but only recently adopted by several of the large panel manufacturers including Canadian Solar, Jinko Solar & GCL.
Why are Monocrystalline cells more efficient?
The inherent benefits of monocrystalline silicon are due to the uniform crystalline structure free of grain boundaries and lower impurities through the unique czochralski manufacturing process. Mono cells have a lower rate of light induced degradation (LID) and also a slightly better temperature coefficient as explained in detail below. In comparison, poly or multicrystalline cells have very small but defined crystal boundaries which can act as minute barriers and reduce efficiency. Mutlicrystalline cells while generally very reliable and long lasting, can be more susceptible to forming micro-cracks after many years of use.
High Temperature Performance
The power temperature coefficient is the amount of power loss as cell temperature increases. All solar cells and panels are rated using standard test conditions (STC - measured at 25°C) and slowly reduce power output as cell temperature increases. Generally cell temperature is 20-35°C higher than the ambient air temperature which equates to a 8-14% reduction in power output.
Power temperature coefficient comparison - Lower is more efficient
Polycrystalline cells - 0.4 to 0.43 % /°C
Monocrystalline cells - 0.35 to 0.40 % /°C
Monocrystalline IBC cells - 0.29 to 0.31 % /°C
Monocrystalline HJT cells - 0.25 to 0.27 % /°C
Monocrystalline IBC cells, described in more detail below, have a much lower temperature coefficient of -0.30% /°C compared to standard polycrystalline and monocrystalline cells. However, the best performing cells at elevated temperatures are the heterojunction (HJT) cells such as those from Panasonic and REC which we describe in the last section of this article.
PERC - Passivated cells
Over the last few years PERC has emerged as the preferred technology for many manufacturers in both mono and poly crystalline cells. PERC stands for 'Passivated Emitter and Rear Cell' which is a more advanced cell architecture using additional layers on the rear side of the cell to absorb more light photons and increase total 'quantum efficiency'. A common PERC technology is the local Al-BSF or local Aluminium Back Surface Field (see diagram below). However, several other variations have been developed such as PERT (passivated emitter rear totally diffused) and PERL (Passivated Emitter and Rear Locally-diffused).
The director of the Australian Centre for Advanced Photovoltaics at UNSW, Professor Martin Green invented the PERC concept which is now widely used by most solar panel manufacturers around the world.
Q cells were the first in incorporate PERC technology into mulitcrystalline cells but use the name Q.antum for their range of PERC modules. Jinko solar recently broke the solar efficiency record with 24.79% recorded from a monocrystalline N-type PERC cell. Mono PERC cells are now the most popular and efficient cell type with most manufacturers including Winaico, Trina Solar, Q cells, LONGi Solar, Jinko Solar, Risen and JA Solar now all using PERC cell architecture.
Multiple / Wire Busbars - MBB
Busbars are thin wires or ribbons which run down each cell and are visible on most solar panels. Busbars perform two main functions, they collect the electrons from the small fingers on the cell surface, and interconnect the front of the cell to the rear side of the adjacent cell creating a circuit throughout the panel. As PV cells became more efficient they generated more current and over recent years most manufacturers moved from 4 or 5 standard ribbon busbars to 6 or 9 multi-busbars (MBB). Some larger format cells, such as the 210mm cells developed by Trina Solar, have 12 busbars while the REC Alpha range has an impressive 16 micro busbars.
An additional benefit of more busbars is if a cell micro-crack occurs due to impact, heavy loads or people walking on panels, more busbars help reduce the chance of the crack/s developing into a hot spot as they provide alternative paths for current to flow.
LG was the first manufacturer to use round micro-wire busbars on the Neon 2 range of panels. LG called this 'Cello' technology which stands for 'cell connection, electrically low loss, low stress and optical absorption enhancement'. To translate, the Cello multi-wire technology lowers electrical resistance and increases efficiency.
Split Modules with Half-Cut Cells
Over the last few years, most leading manufacturer’s have shifted to using half-cut or half-size cells rather than the traditional full-size square cells. The square cells are laser cut in half and assembled into two groups of cells (upper and lower) that work together in parallel. This cell configuration has multiple benefits including increased efficiency due to lower resistive losses through the bus bars as each group of cells operates at the same voltage but half the current. The lower current also results in lower cell operating temperatures helps reduce the potential formation and severity of hot spots due to localised shading, dirt or cell damage. Additionally, since each group of cells is half the size, the busbar distance is reduced by half which means smaller busbars can be used resulting in less busbar shading losses and increased efficiency.
More recently, a number of manufacturers such as Trina Solar have started producing extra-large 210mm square cells which can be cut into three sections, known as 1/3-cut cells. These large format cells are used to produce high-powered panels up to 600W.
Improved shade tolerance
One of the greatest benefits of split-cell panels is when the are partially shaded. If the upper or lower section of the panel is shaded it does not affect the performance of the unshaded section. This is due to the two sections, or groups of cells, being connected in parallel and acting much like two small individual panels. During partial shading, the voltage is maintained and current loss is reduced by 50%, resulting in far better system performance when partially shaded.
BiFacial Solar Modules
Bifacial solar technology has been available for several years but is starting to become popular as the cost to manufacture the very high quality monocrystalline cells required continues to decrease. Bifacial cells absorb light from both sides of the panel and in the right location and conditions can produce up to 27% more energy than traditional monofacial panels. Bifacial solar panels typically use a glass front and clear rear polymer backsheet to encapsulate the cells which allows reflected light to enter from the rear side of the panel. Bifacial modules can also use a glass rear side which lasts longer and can significantly reduce the risk of failure, with some manufacturers now offering 30 year performance warranties on bifacial panel models.
Traditionally bi-facial solar panels were only used in ground mounted installations in unique locations where the sunlight is easily bounced or reflected off the surrounding surfaces, in particular snow-prone regions and extreme latitudes. Although they have been proven to work well when ground mounted over light sandy surfaces and are also able to achieve up to 10% higher output even on light coloured rooftops when tilted. Manufacturers producing bifacial solar panels include LG energy, Trina solar, Jinko Solar and Yingli Solar.
Dual Glass Panels
Many manufacturers are now producing what is known as glass-glass, dual glass or double glass solar panels which should not be confused with bifacial technology. The rear glass replaces the traditional white EVA (plastic) backsheet and creates a glass-glass sandwich which is considered superior as glass is very stable, non reactive and does not deteriorate over time or suffer from UV degradation. Due to the longer life of glass-glass panels some manufacturers such as Trina solar are now offering 30 year performance warranties.
Many double glass panels are also frameless having no aluminium frame which can complicate the mounting of panels as special clamping systems are required. However, frameless modules offer several advantages especially in regards to cleaning, with no frame to catch dirt and dust the frameless modules when tilted or flat are much easier to clean and are more inclined to aid from wind and rain to self-clean which results in greater solar output. However without the strength of an aluminium frame double glass panels, although more durable, are not as stiff and can appear to flex or bow, especially when mounted flat or horizontal.
Shingled cells are an emerging technology which use overlapping thin cell strips that can be assembled either horizontally or vertically across the panel. Shingled cell are made by laser cutting a normal full size cell in to 5 or 6 strips and layering them in a shingle configuration using rear side connection adhesive. The slight overlap of each cell strip hides a single busbar which interconnects the cell strips. This unique design covers more of the panel surface area as it doesn’t require front side busbar connections which partially shade the cell, thus increasing the panel efficiency much like IBC cells explained below.
Another benefit is that the long shingled cells are usually connected in parallel which greatly reduces the effects of shading with each long cell effectively working independently. Also shingled cells are relatively cheap to manufacture so they can be a very cost effective high performance option, especially if partial shading is an issue.
Seraphim were one of the first manufacturers to release shingled cell modules with there high performance Eclipse range of panels. The SunPower P series are a more recent addition to the SunPower range offering a lower cost option primarily for large scale applications. Other manufacturers producing shingled cell solar panels include Yingli Solar and Znshine.
To further boost panel efficiency manufacturers started introducing techniques to eliminate the vertical inter-cell gap between cells. Removing the standard vertical 2-3mm gaps between cells results in more of the total panel surface area being able to absorb sunlight and thus generate power which in turn increases total panel efficiency. This might sound like a relatively simple modification but the small gap provides space for the busbars to bend and interconnect the cells from the front side of one cell to the rear side of the adjacent cell.
There are several techniques being developed to minimise or eliminate the intercell gap with the most common being to simply reduce the gap from around 2mm to 0.5mm as some space is still needed for the busbar interconnection. Traditional large ribbon busbars required several millimetres of space to bend between the front and rear of the cells. However, the transition to using much smaller multi-busbars has enabled the gap to be reduced significantly.
To achieve this JinkoSolar developed what the company refers to as Tiling Ribbon or TR cells. Tiling Ribbon technology eliminates the inter-cell gap by slightly overlapping the cells and using a compression joining method. Tiling ribbon cells also dramatically reduces the amount of solder required which reduces the amount of silver needed making the panels both cheaper and more environmentally friendly.
IBC Cell Technology
IBC or Interdigitated Back Contact cells have a grid of 30 or more conductors integrated into the rear side of the cell, unlike traditional cells which have 5 to 6 large visible ribbon busbars and multiple fingers on the front side of the cell. The most obvious problem with the more common front exposed busbar design is they partially shade the cell and reflect some of the light photons which reduces efficiency. IBC cells don't suffer this problem and as a bonus look much 'cleaner' with no exposed busbars.
High strength and durability
IBC silicon cells are not only more efficient but much stronger than conventional cells as the rear layers reinforce the whole cell and help prevent micro-cracking which can eventually lead to failure.
Sunpower use a high grade, solid copper IBC rear foundation layer on their patented 'Maxeon' cell design along with a highly reflective metal mirror like surface to reflect any light which passes through back into the cell. The rear side of the 'Maxeon' IBC cell shown below is extremely tolerant to stress and bending unlike conventional cells which are relatively brittle in comparison.
High efficiency N-type Solar cells
While PERC and bifacial are the talk of the solar world the most efficient and reliable technology is still the N-type monocrystalline cell. The first type of solar cell developed in 1954 by Bell labs used an N-type doped silicon wafer but over time the more cost effective P-type silicon became the dominant cell type with over 80% of the global market in 2017 using P-type cells. With high volume and low cost being the main driving factor behind P-type it is expected that N-type will become more popular as the manufacturing costs reduce further and efficiency increases.
Heterojunction - HJT cells
HJT solar cells use a base of common crystalline silicon with additional ultra thin-film layers of amorphous silicon on either side forming what is known as a heterojunction. The additional amorphous silicon layers reduce what is known as recombination at the N-P junction which essentially means it reduces loses and increases cell efficiency.
Panasonic created the efficient 'HIT' range of panels and were the leaders in HJT cell technology for many years. REC group also recently released the Alpha series panels which use half-cut HJT cells combined with 16 micro busbars (16BB) to achieve an impressive 21.7% panel efficiency.
The unique Panasonic HIT panels are available in Japan and North America, unfortunately they are not available in Australia. Considering the high average temperatures in Australia they would be a great choice for rooftops and large scale commercial applications.
Improved high temperature performance
The most impressive characteristic of HJT cells is the incredibly low temperature coefficient which is around 40% lower compared to common multi and mono silicon crystalline cells. Solar panel power is rated under Standard Test Conditions (STC) which is measured at a cell temperature of 25°C. Every degree above the STC temperature reduces power output by a small percentage known as the power temperature coefficient. In common multi and mono cells, the temperature coefficient is 0.38% to 0.42% per °C which can add up to reduce total output by up to 20% during very hot windless days. In comparison HJT cells have an very low 0.26%/°C temperature coefficient.
Note: panel and cell temperature is also effected by roof color, tilt angle and wind speed, so mounting panels flat on a very dark rooftop will usually reduce panel performance compared to lighter colored rooftops.