Photo: TÜV Rheinland In the PV+Test mechanical loading tests, solar photovoltaic modules are first subjected to a load of 2,400 pascals and then to 5,400 pascals. A new entry in the list of the best modules PV+Test: For the first time ever, a Chinese manufacturer has decided to release the results of the TÜV Rheinland and Solarpraxis module test. The Jetion Solar JT235PCe module passed the most demanding testing regime with the score of good+. Chinese solar modules are not necessarily of poorer quality than modules produced in Europe. The 60 cell JT235PCe, made by Jetion Solar in Jiangsu province is proof of this claim. The module scores particularly high marks for its temperature coefficient, a value which describes the drop in performance of a module as ambient temperature rises. Good temperature behavior can make a positive contribution PV+Test: List of the best modules Ranking Points Score Manufacturer Module 1 94.3 excellent Solon Solon Blue 230/07-235W 2 91.3 excellent (-) Schott Solar Schott Poly 290 3 90.7 excellent (-) Sharp NU-180E1 4 89.8 good (+) IBC Solar IBC Monosol 240 ET 5 89 good (+) Mitsubishi Electric PV-TD185MF5 6 88.5 good (+) Jetion Solar JT235PCe 7 88.1 good (+) Conergy PowerPlus 225P 8 84.3 good Sovello SV-X-195-fa1 9 80 good (-) Perfect Solar PS230-6P-TOP to energy yield. The relative performance degradation of 0.416 percent per kelvin of the JT235PCe is better than any module ever tested. Only the Conergy PowerPlus 225P module, with a score of 0.419 percent even comes close. The average temperature coefficient of other modules subjected to the test is 0.453 percent. The worst score of any module so far was 0.491 percent per kelvin. The average output of the five test samples conformed with the manufacturer s positive output sorting data, even though one of the modules measured approximately one percent lower than the minimum nominal output value of 235 Watts, slightly lowering its test score. 90
The Jetion module performed less well in low-light conditions. To test low-light behavior, TÜV Rheinland measures the performance of a module at 200 Watts per square meter of irradiance. Test: Jetion JT235PCe Chinese manufacturer Jetion Solar offers the JT235PCe module in a standard series with nominal outputs ranging from 225 to 245 Watts. Special solutions are also available on request. According to the company, the module is used mostly in large-scale roof and ground-mounted projects, but it is also used in small systems. A hollow frame provides the necessary support for loads of up to 5,400 pascals. Condensation drains out of openings on the bottom of the module. According to Jetion, the 3.2 millimeter thick glass has low iron content, is highly transparent, anti-reflective, and coated to ensure very high yield. The Jetion module has been available on the European market since 2007. Since then, some 400 megawatts of modules have been sold under the Jetion brand name in Europe. The company is also an OEM manufacturer for other solar companies. Under other brand names the Jetion has produced modules with a total capacity of about one gigawatt. Since the end of 2011, the company has manufactured its Italus series modules for the Italian market. The Italus modules conform to the guidelines of the Conto Energia, which brings a ten percent higher feed-in tariff in Italy. Weak low-light behavior During this test, the efficiency of the JT235PCe dropped by 4.5 percent. The module s score is not the worst among those tested, but it does come in at the lower end of the spectrum. The average value of modules tested so far is 1.6 percent. Two of the modules actually show higher efficiency in low-light conditions than they do under standard test conditions. The Solon Blue 230/07-235W had an efficiency that was 1.25 percent better, and the efficiency of the Sharp NU-180E1 climbed 2.14 percent in the low-light performance test. The Jetion modules practically sailed through the electrical safety tests, receiving the highest possible score in the technical documentation category. It was docked a few points because the specification sheet did not provide any electrical values for nominal operating cell temperature (NOCT) conditions (800 Watts per square meter of irradiance under module operating temperature), and there was no value for the efficiency changes under low-light conditions. The module received the highest number of points for the validity of its design certifications in accordance with IEC 61215, and the safety test performed in accordance with IEC 61730. The certification tests were performed in China s Yangzhou Opto-Electrical Products Testing Institute, a facility almost unknown in Germany. Photo: Jetion Solar Advertisement
PV+Test results Manufacturer Solon Schott Solar Sharp Module Solon Blue 230/07-235W SCHOTT POLY 290 NU-180E1 Made in Germany Germany Japan Size (millimeters) 1,640 x 1,000 x 42 1,685 x 1,281 x 50 1,318 x 994 x 46 Weight 23.5 kg 41.5 kg 16.0 kg Cell type Polycrystalline 6-inch cells Polycrystalline 6-inch cells Monocrystalline 6-inch cells Module type glass/eva/cells/eva/foil glass/eva/cells/eva/glass glass/eva/cells/eva/foil Performance parameters Specified power 235 watts 290 watts 180 watts Output tolerance (negative/positive, in percent) 0%/+2.1% 0%/not specified -5%/+10% Deviation of measured performance from specified performance +1.7% +2.6% -2.3% Measured performance within the specified performance tolerance yes yes yes Efficiency under STC (1000 watts of solar radiation per m 2, 25 C, measured) 14.6% 13.8% 13.4% Efficiency change at low light levels (200 watts of solar radiation per m 2 ) +1.2% -2.0% +2.1% Temperature coefficient (percent) -0.447% -0.462% -0.424% Efficiency reduction at 50 C (temperature coefficient measured) -11.18% -11.55% -10.60% Fill factor 73.8% 73.3% 69.1% Evaluation of performance variance +++ +++ ++ Evaluation of low-light behavior +++ ++ +++ Evaluation of temperature behavior o - ++ Evaluation +++ +++ + Aging behavior Thermal cycling test (power degradation in percent) -0.6% -2.3% -1.1% Damp heat test, 1000 hours (power degradation in percent) 0.0% 0.9% -3.1% Damp heat test, 1500 hours (power degradation in percent) -1.1% -1.0% -0.2% Mechanical load test, 2400 pascals (power degradation in percent) 0.2% -0.7% -0.3% Mechanical load test, 5400 pascals (power degradation in percent) -1.7% -0.2% -0.3% Evaluation of the thermal cycling test +++ ++ +++ Evaluation of the damp heat test, 1000 hours +++ +++ + Evaluation of the damp heat test, 1500 hours +++ +++ +++ Evaluation of the mechanical load test (2400 pascals) +++ ++ +++ Evaluation of the mechanical load test, very high load (5400 pascals) +++ +++ +++ none none none Evaluation +++ +++ ++ Documentation IEC 61215/IEC 61730/CE label +/+/+ +/+/+ +/+/+ Inadequate grounding instructions, inadequate interconnection information. No grounding instructions, interconnection information is inadequate. No information on low-light performance, NOCT values missing. Evaluation +++ +++ +++ Electrical safety Results meet requirements of safety standard IEC 61730 yes yes yes none none none Evaluation +++ +++ +++ Processing Sharp edges (test according to UL) no no no Visible irregularities Partly overlaying, partly sticky frame tapes, rippled backfoils on all test samples. Bus bars not covering (> 1 mm), string offset (approx. 2 mm), minor impurities. Solder tabs pressing into backfoil, minor impurities. Electroluminescence - o +++ Evaluation + ++ +++ Warranty and ease of installation Product warranty 10 years 5 years 5 years Performance guarantee 90%/80% 10 years/25 years 10 years/20 years 10 years/25 years Installation, dismantling, and transport are not covered. Comments Relatively heavy (23.5 kg) Large and heavy (41 kg) No information on money-back guarantee. Evaluation +++ + +++ Results within the requirements of IEC 61215 and IEC 61730 yes yes yes Overall Evaluation (maximum 100 points) 94.29 91.3 90.7 SCORE very good very good (-) very good (-) 92
IBC Solar Mitsubishi Electric Jetion Solar Conergy IBC Monosol PV-TD185MF5 JT235PCe PowerPlus 225P Germany Japan China Germany 1,680 x 990 x 50 1,658 x 834 x 46 1,655 x 992 x 40 1,651 x 986 x 46 24.0 kg 17.0 kg 22.5 kg 19.6 kg Monocrystalline 6-inch cells Polycrystalline 6-inch cells Polycrystalline 6-inch cells Polycrystalline 6-inch cells glass/eva/cells/eva/foil glass/eva/cells/eva/foil glass/eva/cells/eva/foil glass/eva/cells/eva/foil Bubbles on the product label after the damp heat test. No information on materials, Pmax tolerance, and protection class; instructions for grounding were inadequate. Partly overlaying adhesive frame tapes, solder tabs not always covering. Installation, dismantling, and transport are not covered. 240 watts 185 watts 235 watts 225 watts 0%/+2.1% -3%/not specified 0%/+2.1% 0%/+2.5% +1.21% -2.0% +0.2% +2.0% yes yes yes yes 14.5% 13.1% 14.4% 14.1% -2.5% -0.9% -4.5% -2.1% -0.465% -0.490% -0.416% -0.419% -11.63% -12.25% -10.4% -10.48% 76.2% 72.4% 75.2% 73.9% +++ ++ +++ +++ + +++ o + - - +++ +++ ++ + ++ +++ -0.38% -0.2% -0.4% -3.8% 1.3% -0.8% -0.4% -1.2% 0.0% 0.4% -0.3% 1.0% -0.8% -1.5% -1.1% -0.6% -0.5% -1.0% -1.0% -0.8% ++ +++ +++ o + ++ + ++ +++ + +++ + +++ +++ +++ +++ +++ +++ +++ ++ String-fixing adhesive tape became visible during the damp heat test; after 1,500 hours, a slight yellowing of the backfoil became visible. Following the 1,000 hour damp heat test, there was discoloration and spots on the product label (but still readable), highly corroded/discolored string connectors, and slightly corroded/discolored cell connectors. After the thermal cycling test, there was leakage current at the plug of one of the two modules. However, the repeat test was successful. After the damp heat test, the junction box sealing was affected. ++ ++ ++ + +/+/+ +/+/+ +/+/+ +/+/+ No information on low-light performance, NOCT values missing, interconnection information inadequate. No information on low-light performance, NOCT values missing, no information on materials used. Inadequate grounding information. +++ +++ +++ +++ yes yes yes yes none none none none +++ +++ +++ +++ no yes no (but slight burrs on the corners) no Solder tabs not covering (> 1 mm) Slightly imprecise silicon adhesion (frame/ junction box), a few solder tabs offset (approx. 1mm). Solder tabs not covering ( 1 mm). +++ +++ - o +++ + + ++ 10 years 5 years 12 years 5 years 12 years/25 years 10 years/25 years 10 years/25 years 12 years (92%)/25 years Relatively heavy (24 kg) Module soldered lead-free, which is a big plus ecologically Installation, dismantling, and transport are not covered. Unclear warranty conditions. Relatively heavy (22.5 kg) The data sheet states a 10-year product warranty, while the warranty conditions do not state this. +++ ++ +++ +++ yes yes yes yes* 89.8 89.0 88.5 88.1 good (+) good (+) good (+) good (+) Table overview Most of the modules that underwent the TÜV Rheinland and Solarpraxis test were ranked as excellent or good and complied with industry standards. The overall score is based on a large number of measurements conducted by TÜV Rheinland, not all of which are included in the table. Each item receives a score from zero to ten, and each of these scores is weighted as part of the overall score. The total scores are ranked as follows: 90 % of the maximum number of points: excellent 80 %: good 70 %: satisfactory 60 %: poor < 50 %: very poor. The sub-items are assessed as: +++/ ++/ +/ o / - The board of advisers of PV+Test defined how the individual scores are to be weighted in the overall score: Performance parameters: 20 % Aging behavior: 25 % Documentation: 15 % Electrical safety: 25 % Processing: 10 % Warranty and ease of installation: 5 % The scoring system for all modules tested up to now is shown on page 94. PV+Test is protected by copyright, and the table can only be reproduced with the consent of Solarpraxis AG and TÜV Rheinland. For more information, see pv magazine 02/2011 and our website (www.pvmagazine.com/pv-test). * Conergy: After the damp heat test, there was leakage current at the plug of one of the two tested modules. However, the repeat test was successful. 93
Manufacturer Sovello Perfect Solar Module SV-X-195-fa1 PS230-6P-TOP Made in Germany Germany/Taiwan Size (millimeters) 1,650 x 951 x 46 1,663 x 997 x 39 Weight 18.6 kg 22.0 kg Cell type String-ribbon cells Polycrystalline 6-inch cells Module type glass/eva/cells/eva/foil glass/eva/cells/eva/foil Performance parameters Specified power 195 watts 230 watts Output tolerance (negative/positive, in percent) 0%/+2.6% -3%/+3% Deviation of measured performance from specified performance +0.3% -1.9% Measured performance within the specified performance tolerance yes yes Efficiency under STC (1000 watts of solar radiation per m 2, 25 C, measured) 12.5% 13.6% Efficiency reduction at low light levels (200 watts of solar radiation per m 2 ) -0.5% -1.0% Temperature coefficient (percent) -0.491% -0.468% Efficiency reduction at 50 degrees (temperature coefficient measured) -12.28% -11.70% Fill factor 70.6% 73.3% Evaluation of performance variance +++ ++ Evaluation of low-light behavior +++ ++ Evaluation of temperature behavior - - Evaluation ++ + Aging behavior Thermal cycling test (power degradation in percent) -5.3% -2.0% Damp heat test, 1000 hours (power degradation in percent) -2.5% -0.4% Damp heat test, 1500 hours (power degradation in percent) -0.3% -1.9% Mechanical load test, 2400 pascals (power degradation in percent) -2.1% -1.8% Mechanical load test, 5400 pascals (power degradation in percent) -0.6% -3.5% Evaluation of the thermal cycling test o ++ Evaluation of the damp heat test, 1000 hours ++ + Evaluation of the damp heat test, 1500 hours ++ o Evaluation of the mechanical load test (2400 pascals) +++ ++ Evaluation of the mechanical load test, very high load (5400 pascals) ++ ++ After the mechanical load test at 5,400 pascals, the wet insulation value was too low. However, the repeat test was successful. After the damp heat test, the cell/string connector solder points were corroded. The damp heat test led to yellowing on the back side. Evaluation + + Documentation IEC 61215/IEC 61730/CE label +/+/+ +/+/- No information on low-light behavior or safety class. No information on safety class, performance tolerances or safety warnings according to IEC 61730. Evaluation +++ + Electrical safety Results meet requirements of safety standard IEC 61730 yes yes none none Evaluation ++ ++ Processing Sharp edges (test according to UL) no no Visible irregularities Electroluminescence Solder tabs not covering (> 1 mm), string offset (approx. 1 mm), minor impurities. Solder tabs not covering, minor impurities. - - Evaluation o ++ Warranty and ease of installation Product warranty 5 years 5 years Performance guarantee 90%/80% 10 years/25 years 10 years/25 years Comments Flaws in technical information in the warranty certificate. Weight greater than 20 kg Evaluation +++ ++ Results within the requirements of IEC 61215 and IEC 61730 yes yes Overall Evaluation (maximum 100 points) 84.3 80.0 SCORE good good (-) Scoring system Modules tested: 14 excellent excellent (-) good (+) good good (-) satisfactory (+) satisfactory poor very poor 1 3 5 2 1 0 1 1 0 94
The Jetion JT235PCe also performed well in the aging resistance tests. The aging tests comprise a 200-cycle thermal cycling test, two damp heat tests one for 1,000 hours and one for 1,500 hours as well as two mechanical loading tests, with loads of 2,400 and 5,400 pascals. Maximum performance degradation following the tests was 1.1 percent, which cost the module a point in the results for that category. The module also lost a few points for low insulation resistance values. Nevertheless, the insulation resistance losses never reached really worrisome levels. Test results and contact Detailed description and all of the PV+Test results: www.pv-magazine.com/pv-test PV+Test website: www.pvtest.de Contact for manufacturers: Michaela Fischbach michaela.fischbach@solarpraxis.de Andreas Cox cox@de.tuv.com Age spots What did stand out was the appearance of discolorations on string connectors and some of the cell connectors after the first 1,000 hour damp heat test. While the spots did not directly affect the performance of the module, points were taken off in that category. The discolorations on the string and cell connectors are indicators of an undesirable chemical process, says Andreas Cox, who is responsible for solar module qualification and PV+Test at TÜV Rheinland. It appears to be only a surface effect, however. At least, there was no indication after the test of performance degradation which would point to higher resistance resulting from corrosion. After the damp heat test the product label also showed signs of discoloration and spotting which had not been visible prior to testing. According to the standard, the product label must always be clearly legible. Also, it should not be easily removed or subject to any kind of manipulation, Cox explains. That is important because the label lists all of the key data for the module. Among these are module performance values and output tolerance data, as well as open-circuit voltage and short-circuit current. Printing a product label for a photovoltaic module is no small matter, according to Cox. If they print it with a normal printer on a standard label, it will be completely unreadable after 20 years. Those are beginners mistakes. In the case of the Jetion module, however, the product label is clearly visible despite the effects of the damp heat test. That is why Jetion only lost a few points in that category. The serial number, which on some modules is also printed on the product label, is printed on a special sticker on the back of the module in addition to being laminated behind the protective glass on the front. Cox believes that laminating the number behind the glass is, a good solution because it prevents manipulation of the serial number. Many module manufacturers are now taking this approach. The Jetion module received zero points in the electroluminescence image category. Electroluminescence measurement is like an x-ray of the module which detects cell breakage and inactive parts of cells. Harmless cracks The modules that went into the thermal cycling test already had cracks in them when they were delivered, Cox explains. But the cracks didn t cause a drop in performance either before or after the test. Cox says that evaluating electroluminescence images is not so easy. Visible cracks do not necessarily result in worse performance. The only time you can clearly measure drops in performance is when big pieces of the cells completely break off. Even though the module performance was unaffected, the visual faults in the Jetion modules were so extreme that we could not award any points in that category. Nevertheless, the JT235PCe cut quite a good profile overall. Despite losing points in some of the categories, the module received a total score of 88.45, securing its place amongst the best. In addition to the Jetion module, a further module underwent the TÜV Rheinland and Solarpraxis test, but the Asian manufacturer of the module was not satisfied. Despite a remarkable final score of very good, the manufacturer decided not to release the results. The decisive factor in the decision was a very poor score in the temperature behavior category. A number of other modules are currently undergoing the PV+Test testing program. We will publish the results as soon as they are available. S Mirco Sieg the PV+TEST Program Modules tested in the PV+Test program are purchased anonymously on the open market to prevent manufacturers from hand-picking, or possibly even pre-testing modules for the test. The test not only examines a few key parameters which can obscure an objective assessment through a heavy weighting, but it also assesses numerous other values, among them, performance parameters, resistance to aging, electrical safety, production quality, and documentation. All of these values combine in different weightings to yield an integrated score which is discussed by an industry council made up of representatives from manufacturers and testing institutes. A single value that falls short of a certain tolerance level can result in a serious drop in the overall score. A detailed test evaluation is published which goes into great depth to give interested readers a detailed view of how modules performed in the individual categories. PV+Test assesses low-light performance data and temperature coefficients which form the basis of yield simulations for specific locations. That is more useful than a short-term yield test at a single location. PV+Test is independent. The organizations that conduct the test the accredited and internationally recognized testing laboratory at TÜV Rheinland, and the engineering services division of Solarpraxis AG, which co-publishes pv magazine have staked their reputations on the independence of the test. That rules out manufacturers exercising influence on the test results or how they are presented. Manufacturers can decline publication of the results, however. Even if they are not published, the results are included anonymously in an overview. This enables PV+Test to offer a list that shows consumers which modules they can really rely on. 95