quality solar panels
There are hundreds of different solar panels on the market which makes it difficult for those not in the industry to select quality panels which will perform over the expected 25 year life of a solar photovoltaic (PV) system. Here we help 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 performance.
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 finanical stablility. 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
Below is our list of the best solar panels available in Australia based on quality, performance, innovation and value, along with feedback from solar industry professionals. See our detailed solar panel quality review here. In summary Sunpower and LG are generally regarded the best quality solar panel manufacturers with longest warranties, highest efficiency and lowest degradation over the life of the panel.
Tindo solar is also worth mentioning as they are the only Australian solar panel manufacturer and are known for producing high quality panels at a competitive price. Although due to the relatively low volume production of 60MW and limited installers available they were not included in the top 10. The current Tindo module available is a 275W poly with a 300W mono PERC module available early 2018.
Solar professionals feedback
In addition to continuous feedback from our solar specialists the clean energy reviews team invite all solar industry professionals and installers to give feedback (positive or negative) from experience with any solar modules.
Latest Solar Cell Technology
Here we highlight many of the latest solar panel and PV technologies offered by the leading manufacturers, plus we list some of the more popular panels available on the market using these innovative features.
Panels using the latest Innovations
Most panel manufacturers offer a range of models including mono and poly (aka multi) 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 - Ribbon and round wire busbars
- Split panels - using half size cells
- IBC - Interdigitated Back Contact N-type cells
These innovations and more explained in detail below offer various efficiency improvements, shade tolerance and increased reliability, with several manufacturers now offering up to 30 year performance warranties.
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. From the well regarded manufacturers there are several panels which have become very popular among Australian solar installers due to high performance, quality, support and value for money.
LG Neon 2 panels - Mono N-type with multi-wire busbars
REC TwinPeak 2 panels - Poly P-type PERC half size cells
Winaico P6 panels - Poly P-type PERC cells
Trina Solar Honey panels - Mono P-type PERC cells
Q cells Q.antum panels - Poly P-type PERC cells
Sunpower E series - Mono N-type IBC cells (Popular in the US)
Mono vs Poly Silicon Cells
There is a long ongoing debate about the superior PV cell technology between monocrystalline and polycrystalline silicon cells. Monocrystalline cells (mono) are cut from a single crystal ingot are more efficient but more expensive to manufacture. The higher cost lead the way for polycrystalline technology to become the preferred cell type used, in particular during the last 5 years. Polycrystalline cells, also known as multicrystalline or 'multi' cells, are grown from multifaceted crystalline material (grown in multiple directions) which is cheaper to produce but offers slightly lower efficiency. Both are still widely manufactured and very reliable but mono cells are considered the the superior technology in regards to efficiency with lower degradation over time.
The Future is PERC
Over the last year PERC cells have emerged as the premium technology for many manufacturers in both Mono and Poly panels. PERC stands for 'Passivated Emitter Rear Cell' which is basically a process which adds an additional layer/s on the back of the solar cell to reflect some of the light photons which manage to pass through the cell back into the cell, thus increasing total efficiency.
Q cells pioneered the PERC technology in mulitcrystalline cells but use the name Q.antum for their range of PERC modules. Jinko solar recently broke the solar efficiency record with 22.04% recorded from a standard size multicrystalline (p-type) silicon cell. PERC technology has been available for a few years and is advancing rapidly with most leading manufacturers developing their next generation panels using variations of PERC technology. It is predicted that Mono PERC cells will become the most popular and efficient cell type over the next few years.
Multiple / Wire Busbars
The busbars are the thin wires or ribbons which run down each cell and carry the electrons (current) through the solar module. As PV cells have become more efficient they generate more current and over the last 5 years most manufacturers have moved from 3 busbars up to 4 or 5 busbars. A few manufactures such as LG energy have gone one step further and developed wire systems using up to 12 very thin round busbars, explained in more detail below. The compromise is that the busbars actually shade part of the cell and so can slightly reduce performance if they are too large, so they need to be very carefully designed. On the other hand multiple busbars provide lower resistance and a shorter path for the electrons to travel resulting in higher performance.
LG energy incorporate a unique technology on their Neon 2 modules using 12 small round wires rather than thin busbars, known an Cello which stands for 'cell connection, electrically low loss, low stress and optical absorption enhancement'. Essentially the Cello Multi wire busbar technology lowers electrical resistance and further increases efficiency.
Trina solar have also recently started offering thin round wire busbar cells under the name multi busbar (MBB) as an option on a range of modules for 2018. Another benefit of MBB or Cello busbars is if micro-cracking does occur in a cell due to external stresses there is less chance of this forming a hotspot as the electrons have many alternative busbars to flow along, as shown in the diagram.
See the complete Trina Solar panel and technology review here
Split Modules and Half size Cells
Another recent innovation is using half cut or half size cells rather than full size square cells and moving the junction box to the center of the module. This effectively splits the solar panel into 2 smaller panels of 50% capacity each. This has multiple benefits with the main being increased performance due to lower resistive losses through the bus bars (current collectors). Since each cell is half size it produces half the current at the same voltage which means the width of the busbar can be reduced by half in turn reducing cell shading and losses.
In addition the shorter distance to the center of the panel from the top and bottom improves efficiency overall can boost power output of a similar sized panel by up to 20W. Another benefit is that it allows partial shading on the upper or lower part of the panel to not effect the entire power output of the panel.
The REC twin peak 2 range of split panels have been available for some time and now many other manufacturers are following suit with split panels being released by Trina Solar, Q-cells, Canadian Solar, JA Solar and Jinko solar.
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 30% more energy than traditional monofacial panels. The bifacial solar panels use a front and rear glass system to encapsulate the cells which is more durable than the traditional plastic laminate back sheet used on regular panels. The glass rear side lasts longer with lower degradation over time 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 backsheet replaces the traditional EVA (plastic) backsheet and creates a glass-glass sandwich which is considered superior as the glass does not deteriorate over time or suffer from light induced degradation (LID). Due to the longer life of glass-glass panels some manufacturers such as Trina solar are also offering 30 year performance warranties.
Most double glass panels are frameless which can complicate the mounting of panels as special clamping systems are required, although 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 the standard aluminum frame double glass panels are more durable but not as stiff as a single glass framed panel and can appear to flex or bow, especially when mounted flat.
Manufacturers producing dual glass solar panels include Jinko solar, LONGi Solar, Trina Solar, Yingli Solar and JA solar.
Smart Panels and Optimisers
A new technology which is slowly becoming popular is the addition of integrated power (DC) optimisers within the solar panel. Optimsers are basically small chipsets which have the ability to bypass shaded or dirty cells that would otherwise reduce the total output of the solar array. Shading and dirt can generate hot spots over time in turn reducing the life of the panel. Separate power optimisers from companies such as Tigo and SolarEdge have been available as an add-on component for many years but now a few manufacturers are developing panels with inbuilt optimisers within the junction box on the back of the panel. Tigo energy TS4 optimisers are available as panel-integrated options or Smart panels from Jinko and Trina Solar. These can be also be added to any existing panel as an add-on optimiser with various options available. See full Tigo specifications here.
A big advantage of 'add-on' optimisers such as those from Tigo and SolarEdge is the ability to monitor each solar panel individually. Micro-Inverters also have this advantage over common string inverters.
Jinko Solar have introduced the Eagle MX range of solar panels using the Maxim Integrated optimiser chips. These smart chips from Maxim Integrated go beyond the traditional add-on optimiser and separate the panel into 3 strings of cells which enables the panel to operate at the optimum MPPT voltage even when partially shaded or dirty. It is worth noting that some installers have reported customers having RFI interference issues (TV & radio) using this new technology however the next generation Maxim chips are claimed to have resolved the RFI problem.
Panel and cell Strength
Along with the many cell advancements to improve efficiency there are also new technologies to increase reliability and performance over the expected 25 year life of a solar module. Solar panels can be put under extreme stress due to wind lift forces, vibrations, extreme heat and freezing cold causing expansion and contraction. These can develop micro-cracks, hot spots and PID (potential induced degradation) within the cells leading to reduced performance and accelerated failure.
Manufacturers such as Winaico and LG energy have engineered extremely strong aluminium frames to help reduce cell and module stresses. Winaico's parent company Win Win Technology have gone one step further and developed what is known as 'HeatCap' Technology which is essentially a cell reinforcement structure that helps prevent mirco cracks and hot spots from forming when cells are under extreme stresses and loading. This technology also has the added benifit of improved performance at higher cell temperatures. Read more about HeatCap here.
IBC cells - Highest strength and flexibility
IBC silicon cells explained in greater detail below are not only more efficient but also much stronger than conventional cells as the rear layers reinforce the whole cell and helps 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 Maxeon N-type cell backing shown below is extremely tolerant to stress and bending unlike conventional cells which are relatively brittle in comparison.
N-type High efficiency 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.
IBC Cell Technology
IBC or Interdigitated Back Contact cells can have 30 or more busbars integrated into the back of the cell, unlike standard cells which typically have 4 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, while IBC cells don't suffer this problem and as a bonus look much 'cleaner' with no busbars showing.
The most efficient solar panels - IBC N-type cells
The world's most efficient and best performing solar panels are manufactured using IBC N-type monocrystalline silicon cells and although they are the most expensive, they are without doubt the most reliable, highest quality panels available. As of 2018 SunPower and LG are the only two manufacturers who supply solar panels with IBC N-type cells to the Australian market.
For many the higher cost of the these premium N-type solar panels ($1 or more per W) is outweighed by the higher efficiency which ranges from 20 to 22%, improved performance at higher temperatures and minimal light induced degradation (LID), which means much higher energy yield over the life of the panel with close to 90% power output warranted after 25 years.
This industry leading warranty is offered on both the SunPower X series and LG Neon R panels. Also as of May 2018 the LG Neon 2 panels are also covered by the same leading 25 year product warranty.