This article is about big solar panels. Bigger than the standard sized 60 cell panels commonly installed on residential roofs. Those are only around 1m by 1.65m. I&#;m talking about larger ones with 72 cells that are about 1m by 2m. These larger panels are mostly used for commercial installations and solar farms, but they can be used on household roofs provided they are installed properly.
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Unfortunately, this doesn&#;t always happen.
One problem with larger solar panels is the clamps holding them aren&#;t always placed correctly. When the proper clamping zones aren&#;t used it generally voids manufacturer warranties as they can suffer damage from being flexed by the wind.
I&#;ll go over the main disadvantages of larger panels and I&#;ll cover their one potential advantage, which is cost. I&#;ll also explain why you should be cautious when it comes to getting a low cost 72 cell solar panel system installed.
What I won&#;t do is spend much time explaining what larger panels are. They&#;re just 20% bigger than usual. It&#;s nothing particularly complex. It&#;s not like the question of why does stale bread get hard but stale biscuits go soft.1
Half cut solar panels are becoming popular. These have their solar cells cut in half to provide a small increase in efficiency. A 144 cell panel is simply a 72 cell one with its solar cells cut in half. Everything in this article about 72 cell solar panels also applies to half cut 144 cell models as they are similar in size and weight, with only slightly different average performance.
Larger 72 cell solar panels are rarely used for home installations due to three main drawbacks:
Smaller solar panels can cover more roof area. If solar panels were the size of mobile phones it would be easy to cover an entire section of roof with hardly any dead space left over. In practice, with standard sized 60 cell panels, it is often impossible not to leave a lot of empty room around the edges. With larger moduels this problem is more pronounced. As a result, a system that uses 72 cell panels can end up with less capacity than if 60 cell modules had been used.
There are various methods for getting solar panels onto roofs but most of the time muscle power is used. And muscles, as well as the joints and ligaments they are attached to, can really start to hurt after lugging a dozen or so panels up onto a roof. A typical 60 cell panel weighs around 19kg while a 72 cell module is around 22.5kg. That may not sound like a big difference, but when hauling them onto a roof it&#;s definitely noticeable. Larger solar panels also catch the wind more, making them unwieldly and harder to handle. This is clearly dangerous when up on a roof.
While using larger panels means fewer need to be carried in total, from the point of view of strains and injuries, it is generally safer to make more trips with lighter loads than fewer trips with heavier loads.
The extra weight of 72 cell panels is not a problem for the roof, as it gets spread out over a similar area as when 60 cell modules are used.
A major drawback of some 72 cell solar panels &#; their main weakness, their Achilles&#; heel, if you will &#; is their clamping zones can be very different from 60 cell panels. Many can only be clamped on their long sides and some have very small clamping zones that leave little margin for error. The smaller the zones and the less motivated an installer is to do quality work, the more likely you are to end up with clamps outside the correct zones.
Under Australian consumer law the installer is required to fix problems caused by their incorrect clamping, but if the installer has disappeared and the manufacturer&#;s clamping recommendations weren&#;t followed, the manufacturer is likely to declare their warranties don&#;t apply.
To find out the clamping zones of a module you will need to check its installation manual. These can normally be downloaded from the solar panel manufacturer&#;s website. JinkoSolar is the world&#;s largest producer of solar panels and many of theirs are on Australian rooftops, so I will use them as an example of how to check clamping zones.
First I went to the Jinko Australian site to download their installation manual but the links weren&#;t working, so I instead found an older version online which was full of useful advice such as:
Then I checked their site again and found it was working properly. So I went to this page and was given a choice between a UL user manual and a TUV user manual. UL is an American standards organization while TUV is a German one and relevant for Australia. (Let&#;s face it, Germans tend to be better at these kinds of things.) So I downloaded an up-to-date installation manual with better English and found the following information on clamping zones:
In the table above the 72 cell panels are in Groups 5, 6, 7, and 8. To work out the clamping zones you have to look at the J and K figures and there are two sets of them. One is for Pa and the other is for Pa. These are measures of how much wind pressure the modules can withstand and in Australia you will want the clamping zones for 5,400 Pa. The clamping zone is equal to the J figure subtracted from the K figure, which makes them 200mm or 20cm which is 10% the length of the module. This better than the clamping zones of their 60 cell panels that are only 14cm or 8% the panel&#;s length.
Here is a diagram showing the clamping zones of a 72 cell REC Peak Energy solar panel:
Its clamping zones are only 10cm across, which is only 5% the length of the panel. This is less than half the length of the 20cm clamping zones on their standard sized panels. This leaves very little room for error and an installer will really have to be on top of things to ensure they are installed correctly.
I downloaded Trina Solar&#;s installation manual from their Australian site, but it only gave information for clamping zones for 2,400 Pa of wind pressure when you want them to be clamped for 5,400 Pa. So I looked online and found a different Trina installation manual with this diagram:
The writing is a little small but it says to withstand 5,400 Pa of positive (downwards) wind pressure the clamps have to be located on its long sides between one eighth to one quarter the distance from the corner. This makes the clamping zones for their 72 cell panels 24.5cm, which is 12.5% the module&#;s length.
Here&#;s a diagram from the Canadian Solar installation manual that recommends 3 roof mounting rails and 6 clamps be used for their large CS1U-MS panel:
When 6 clamps are used the clamping zones are 10cm, which is 5% the length of the panel. Four clamps will suffice but the clamping zones are only 8cm across, which is 4% the length of the panel. This allows even less margin for error than REC 72 cell solar panels.
Some solar panels give a choice between clamping zones that are suitable for high wind and lower wind locations. In Australia the highest wind clamping zones should always be used. Even if you live in a low wind area you never know when giant willy willy might come through and cock things up.2
Standard sized 60 cell solar panels are usually rated for up to 1,000 volts while most 72 cell panels are rated for 1,500 volts. But in Australia the highest voltage allowed for residential solar is 600 volts, so it should make no difference for home solar power &#; provided they are installed correctly.
Unfortunately, shoddy installers sometimes don&#;t allow for larger panels having higher wattage ratings and install them as though they were they were standard sized solar modules. This can result in the system&#;s DC voltage exceeding Australian standards and the inverter&#;s limits, potentially creating a dangerous situation.
There is only one potential advantage to using 72 cell solar panels and that is money.
When it comes to cost per watt, 72 cell panels can be slightly cheaper than their smaller 60 cell cousins. Greater savings can come from requiring less roof mounting hardware such as rails and clamps per watt of panel capacity and since fewer panels need to be installed this can save on labour.
Then there are solar companies that pay their subcontracted installers per panel. This means they have an incentive to sell larger panels so they don&#;t have to pay their subcontractors as much.
All this means a 5.4 kilowatt solar system with 15 large 72 cell panels of 360 watts each could be offered at a lower price than a system of same capacity that uses 18 standard sized 60 cell modules of 300 watts each.
But it&#;s only possible for larger solar panels to save on costs if installing them only requires the same number of roof mounting rails and clamps as standard sized modules. It&#;s recommended that 3 roof mounting rails and 6 clamps be used for some, which will significantly increase the cost per watt of the system.
There&#;s no reason why 72 cell panels can&#;t be installed every bit as well as 60 cell solar panels provided there is suitable space available on the roof. Because they can potentially save money they may seem like a good idea. But it pays to be cautious because not all 72 cell panels are installed well due to there being two types of installers who use them:
The problem is telling them apart.
In case you aren&#;t clear on what I mean by cheap bastards, I am referring to solar installers who are competing on price and willing to cut corners and sacrifice quality to keep their prices low. You want to avoid them because if you don&#;t you&#;re far more likely to have a problem with your system. Additionally, because providing after sales service costs money they&#;ll do the absolute minimum they can legally get away with and sometimes less than that.
Because of cheap bastards I don&#;t recommend leaping at an offer of a low cost 72 cell panel solar power system. Doing some research first is definitely be a good idea. One thing you can do is look up the installer&#;s online reviews and see if the large majority of people are happy with their work3.
If they are pushing 72 cell solar panels without knowing details about your roof or your needs I&#;d consider that a bad sign as it suggests they want what&#;s cheap for them to install rather than what&#;s suitable for you.
Under the right circumstances 72 cell solar panels can be every bit as suitable for a household roof as standard sized 60 cell modules. Despite this, not many people I consider to be high quality installers use them, despite the potential for cost savings.
This may seem odd because they are running businesses and keeping costs down is important. But I think it is simply due to the following factors:
While it is possible more 72 cell solar panels will be installed on large home roofs as installers seek out cost savings, I don&#;t expect to see any large shift to using them residentially.
Going solar can be a challenging process for homeowners &#; especially when speaking with different solar companies yields conflicting and confusing information. But when done right, the economic and environmental benefits of rooftop solar are more than worthwhile.
So we asked solar industry veteran Brian Lynch a simple question: What can homeowners do to set themselves up for a successful solar installation?
The company is the world’s best 72 Cell Solar Module Exporter supplier. We are your one-stop shop for all needs. Our staff are highly-specialized and will help you find the product you need.
Lynch broke his answer into 10 questions that homeowners should ask themselves before signing a deal and also threw in some expert advice for answering those questions that he&#;s picked up over his 15+ years with major solar players like REC, LG, and ADT.
Whether you&#;re comparing quotes on the solar.com marketplace or seeking them out on your own, ask yourself the following questions before you sign a solar agreement.
Rooftop solar is a major investment in lowering your electricity costs and carbon footprint, so it&#;s crucial to work with a reputable company that has a proven track record of excellent workmanship and customer service. Research the installer whether or not they are performing the sale.
As a baseline, they should have:
Brian Lynch&#;s advice:
For a truly unbiased opinion, call the local inspector&#;s office and ask if they believe the contractor performs quality work.
Not every solar panel, inverter, and battery is created equal. For example, certain panels and inverters are better suited for roofs with occasional shading than others. And if you&#;re relying on your solar system to reduce your electricity costs, it&#;s important to invest in the right technology.
Ask yourself the following question: Did the salesperson simply propose what they stock or did they select the right technology package for your specific application? Better yet, ask the salesperson why they chose the equipment they did.
Brian Lynch&#;s advice:
Research the equipment companies, their ratings, and whether they have US-based customer service &#; it might make all the difference in the world in a few years if something goes wrong.
Related reading: Best Solar Panels and Inverters Brands of
Successful solar projects begin with setting goals. Some homeowners want to zero out their utility bill, others want to reduce their environmental impact, and a growing number are motivated by backup power and energy independence. Honing in on one or two primary goals can help you and your advisor craft a custom solution to meet them.
Brian Lynch&#;s advice:
It&#;s okay to have several motivations for going solar, but narrow it down to one or two primary goals to guide your system design.
Once you have goals in place, make sure the proposals you receive actually meet them. Every homeowner and every project is unique. Did the salesperson develop a custom proposal based on your feedback, utility usage, and goals for going solar? Or did they simply propose what the roof could fit?
Ask the salesperson or advisor how the equipment, design, and financing options were selected to help meet your goals.
Brian Lynch&#;s advice:
Dealing with an unbiased advisor or advocate versus a commissioned salesperson can make all the difference in the world.
We&#;ve all seen the ads promising &#;free&#; solar. Simply put, there&#;s no such thing &#; and these misleading ads set unrealistic expectations for homeowners looking to lower their essential energy costs. Companies that rely on click-bait like &#;free solar&#; likely have no issues lying to you later in the process.
Going solar is a great way to lower and flatten your essential electricity costs over time. But if the numbers sound too good to be true, they almost certainly are.
Brian Lynch&#;s advice:
The best way to identify and avoid solar scams is to get multiple quotes from reputable installers. This will give you a sense of fair pricing in your market and expose outliers that are too good to be true.
Sounds crazy, but there&#;s a dark side of solar. Reports have been issued by Universities that expose forced labor practices in the upstream supply chain of some solar companies and there have been many investigations into illegal trade practices.
While the US is combatting forced labor in the solar supply chain with tariffs and the Uyghur Forced Labor Prevention Act in , there are still panel manufacturers trying to circumvent these safeguards.
Brian Lynch&#;s advice:
The best way to avoid enabling unethical practices is to work with reputable companies that don&#;t have Chinese ownership ties.
Again, there&#;s no right or wrong answer here as everyone has different financial circumstances and goals. But there are pros and cons to all of the buying panels (with a loan or cash) and leasing them.
In general:
Brian Lynch&#;s advice:
Discuss and simulate several finance options with an unbiased advisor to craft a payment plan that best meets your goals.
Investing in energy storage &#; aka solar batteries &#; along with your solar array is a great way to &#;future proof&#; your solar investment. Battery storage provides energy security and allows you to use your electricity when it&#;s best for you. But, it comes with a substantial cost, and understanding whether an energy storage system is right for you is worth exploring.
Brian Lynch&#;s advice:
Consider the long-term economics. Battery storage costs substantially less when it is installed at the same time as solar panels than if it&#;s added to a solar system retroactively.
Do you trust what you&#;ve been told? Do you trust the equipment? Do you trust the installer? Do you trust that this is the right system for you?
If the answer to these questions is yes &#; then solar is amazing. If the answer is no to one or more of them, find a partner that will build and earn your trust.
Brian Lynch&#;s advice:
With today&#;s solar systems expected to last 25+ years, installing solar means entering a long-term relationship with your installation company and equipment manufacturers. Trust your project to an installer you trust will be around to promptly service your system and help you file warranty claims if issues should arise.
Solar shouldn&#;t be high-pressure gimmicky sales with three-card monte discounting. Solar should be thoroughly explained, researched, and priced in a fair and consultative manner. If you&#;re confident in your decision to go solar then congratulations &#; you&#;ve made a fantastic decision. If not, take the time to evaluate your options
Brian Lynch&#;s advice:
Take the time to fully understand, consider, and establish confidence in your decision to go solar. Don&#;t let a salesperson rush your decision.
If you want to learn more, please visit our website 72 Cell Solar Module Custom.