These Grade specifications for modules have changed over time and by manufacturing companies in different parts of the world.
\r\nAt the Photowatt PV Factory, in the 70’s, where I used to work, module grades were based on output only. It had nothing to do with how a module looked. An A grade module was 10% above the rated output, a B grade module was right on, and a C grade was 10% below. In other words, if it was a 100 watt module, the A’s were about 110 watts, the B’s were about 100 watts and the C grade modules were about 90 watts. Orders will filled pretty much by the luck of the draw.\r\n\r\nThe smartest customer we had at the time, Gene Hitney, one of the pioneers of the PV industry, would always come in by the back loading dock and he’d scope out the modules before getting to the sales center, up front where I worked. So he already knew more about the stock then I did. Usually, he’d manage to cherry pick us to death for our best inventory.\r\n\r\nAt Photowatt small minute cosmetic imperfections were allowed. Modules with larger cosmetic imperfections were thrown in the garbage at the end of the assembly line, that is, until I or the technicians, started asking for them. Those and the low power modules were sold to a guy who was friends of the General Manager and he resold them to the sailors. Nowadays, factories, with much larger production volume, just create new modules with new model numbers and data sheets for these larger quantities, of lower output but perfectly good modules.\r\n\r\nIn the 70’s and early 80’s every manufacturer had a + or – 10% power output allowance, and 10 year warranties were standard. Then came the warranty war, from 15 years to 20, 25 and then one company even offered a 30 year warranty a few years ago but no mfrs. followed them. No one cared, 25 years was long enough, I think.\r\n\r\nIn the 90’s and 2,000’s, Suntech, the world’s largest manufacturer, used different wording for grades, Perfect grade, then A, then B Grades. Their Perfect grade was actually just an A grade, A grade equaled a B, and B grade was a grade C, if you compared their module grades to all the other manufacturers.\r\n\r\nFor a long time, in some places, like China, many manufacturers didn’t know what the difference was between a grade B or C. For them any module that was not an A grade was simply a Grade B and it ends right there.\r\n\r\nThe basic difference between a B and an A, is that B grade modules have slight minute cosmetic imperfections that are almost imperceptible to the eye. 12 years ago we got a call one day Alan King from Evergreen. He said, I’ve got a lot of B Grade modules here would you be interested in them. The price was about 35% less than their A Grade. They had the same warranty, 25 years and UL so I said sure. There was a huge demand at the time from Europe (especially the German’s) but they wanted nothing to do with B Grade, so we had them all to ourselves. Then they changed their minds after we sold many tens of thousands of them into Europe and they bought them all at a higher price and installed them on solar farms, and commercial and residential applications.\r\n\r\nWe got another call from Alan and he said he had C Grade at 45% less than A Grade. We ordered a pallet to look at them and they were 95% identical to B Grade. They did not have UL or a Warranty . Christy my daughter and our Phoenix sales team took an A, B and a C Grade module of 250 watts ea. to a PV show and displayed them side by side at our booth and asked people to identify which was which and basically, no one could do it. The prices were substantially different and the lifetimes were identical. Only the warranty and the certification on the C Grade was substantially different.\r\n\r\nhe basic difference between a grade B and a grade C is that C grade modules are have the same type of cosmetic imperfections but just more of them and they’re larger. But even most C grade modules’ imperfections are difficult to spot unless someone shows them to you from 7 feet away.\r\n\r\nB grade cosmetic imperfections include a tiny chip on the edge or corner of a couple cells, a scratch on a frame, a scratch on the glass, a bubble under the tedlar backskin, a few missing gridlines on a cell, a small piece of foreign matter under the glass, a slightly discolored cell and micro-cracks. C grade cosmetic imperfections are exactly the same B Grade but there are more of them. They are still usually very difficult to see from 8 away.\r\n\r\nMicro-cracks are small invisible cracks you can usually only see in an electro-luminescence testing machine on the assembly line. Basically the mfrs. put the panel in front of a special bright light, if there are any major micro-cracks they take these modules and separate them. The substantial majority of micro-cracks occur mainly after the modules have been manufactured and passed this inspection. The handling: packing, transportation and the installation cause the most.\r\n\r\nKyocera Solar, where I worked for 6 years, allows A grade modules to have small chips on the cell edges but they will only tolerate a certain size chip about 1 mm by 1 mm, I believe, and on just a couple cells like that. They have no B modules, per say, but rather, if there is a small cosmetic imperfection they actually repair them in the factory. I have toured the Kyocera plant and actually saw the tolerance allowances and the location where they “operated” on these modules and turned them into “perfect” looking modules again. Or, they catch the grade B cells before the module assembly and manufacturing and sell them to other manufacturers in China, India, etc. to be cut and made into garden, pathway, decorative lights.\r\n\r\nDozens of the world’s top name brands have sold us tens of thousands of B and C grade modules over the years, including Kyocera, Mitsubishi, Sanyo, Sharp, Astronergy, Topoint, AUO, LG, Suntech, Suniva, Solar World, Solarex, BP Solar, Sungen, Dupont, Photowatt, Sovello, GE Solar, Apollo Solar, Schott, Evergreen, Sovello, and many others. If they weren’t safe, you can be sure they would not be selling them to us.\r\n\r\nThey like to sell them to us, because we can sell them outside of the country where they will not disrupt their distribution networks. And, because of the size of our international distribution network, They also know that we can be trusted to respect and protect the safety of our customers and those that use these modules. We make sure that everyone we sell to, knows that the only use of these modules is for battery based, low voltage (12, 24, or 48 volt) off-grid or hybrid systems.\r\n\r\nGrade D modules are generally considered unusable and thrown out. They include modules with broken glass, short circuits, or modules with cracks that are horizontal, across a cell, and that intersect all the bus bars (usually two or three per cell) on the surface of the cells. Modules with cells like this are destroyed or in rare cases, (Kyocera is the only company I have ever seen that does this), are repaired.\r\n\r\nI was told once by an employee at GE Solar that If you had shaded a large array, and you shaded just one cell (say with a leaf) and that cell had a major micro crack crack, and it was a grid tied system (they use high voltage (approximately 300 volts), you could have serious hot spotting. A hot spot short and can go to 300 degrees F. in about 1 min. Luckily modules made with glass have an extremely difficult time burning. According to the Insurance Industry research we had done by our Hartford Insurance Agent, there has never been a case of any house burning because of solar modules.\r\n\r\nWe regularly sell Perfect Suntech, and A, B, and C modules from some of the largest manufacturers in the world who gladly sell them to us without fear of anyone’s house burning down. We are talking about some of the largest module manufacturers in the world here. Almost all of these modules come with flash test reports attached to the top of each pallet and in every case it shows B and C Grade modules put out exactly the same power as their Grade A modules and the same lifetime.\r\n\r\nI have worked in the solar industry for 37 years, for 3 U.S. Congressmen, the Governor of Arizona’s Arizona Solar Energy Commission, Photocomm, Photowatt Int., and Kyocera Solar Int. and have owned my own solar electric company for 20 years. Grade B, C, and in some cases even D modules are the best thing that ever happened to the PV Industry. The drop in prices for these readily available modules is astonishing.\r\n\r\nIn the last 20 years we have sold about 40,000 Grade B, C, and a few carefully selected D modules. Most of the B and C have been Evergreen Solar Modules.The Evergreen Ribbon Technology is one of the only different crystalline modules because it uses only a fraction of the silicon of any other crystalline module made in the industry today. When the cost of silicon shoots up the competitive value of this efficient manufacturing technology keeps Evergreen Modules in high demand. This Ribbon technology was developed by MIT and Mobile Oil Int. then purchased by Evergreen Solar in Mass., it’s an American Company.\r\n\r\nTo this day we have never had one Evergreen B module come back. There has never been a module short reported either. We make it a point to tell people that our own brand of C grade modules should only be used for low voltage applications like off grid independent homes or systems with 12, 24 and 48 volt battery banks.\r\n\r\nThe result of not just destroying less than Perfect modules has been a blessing to thousands of people as it has enabled them to have a better life or to get a PV system at a significantly lower price.\r\n\r\nThe most popular solar company on the internet is not always the best company to buy your modules from. Home Depot, Wholesale Solar and most others on the first page of Goggle under the search term Solar Panels, sell their PV modules at a set price rather than an easy to compare $/watt price. For single modules, Wholesale Solar’s site does offer $/watt pricing on about a dozen modules. Those dozen modules average a $/watt price of approximately $1.07/watt.\r\n\r\nHome Depot has never had $/watt pricing. Their most popular brand, Grape Solar, sells for $$370 or $1.39/watt for a 265 watt module. For over 25 years, Sun Electronics has always shown their modules in $/watt prices, this is very important. Our current best prices are $.48 to $.58/watt for grade A with major brand names,\r\n\r\nOur current advertised price on Grade B modules is $.19/watt to $.26/watt from Sharp Solar. They come with a 20 year warranty and are in stock in our warehouse not someone else’s.\r\n
\r\nThank you and have a great day.\r\n\r\nJohn Kimball\r\n\r\nOwner\r\n\r\nCell 305-498-1863\r\n\r\nCall me anytime.