Troubling solar-panel defect rate seen (???)

SolarBuyer, a company that audits solar factories, has found defect rates averaging about 8 percent among panels that have not yet been shipped to customers. With some manufacturers, the defect rate has topped 20 percent.
That eye-popping number is an exception, not the rule. But faulty panels are a concern for the solar industry. The number of panels being installed around the world is surging, jumping 44 percent in the United States during this year's third quarter. Quality problems could slow that growth if consumers start to question solar's reliability.
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"A large percentage of them are in survival mode, and when you're in survival mode, you may make decisions you wouldn't make in steady-state mode," said Jenya Meydbray, chief executive officer of PV Evolution Labs. His 2-year-old Berkeley firm tests solar modules.
"We have definitely seen some manufacturers use materials that do not last, that degrade in the tests we do," Meydbray said.
Problems aren't confined to smaller, little-known manufacturers. Nor are the defects limited to panels made in a particular country. The bulk of the world's solar panels are manufactured in Asia and the United States.
First Solar, one of the industry's dominant players in the United States, took a $164 million charge to its earnings last year to cover replacement costs for defective panels. A manufacturing problem affected between 4 and 8 percent of the panels the Arizona company made from June 2008 through June 2009, a First Solar spokesman said.
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Defects often involve either manufacturing glitches or problems with the materials used. Meydbray said one of the most frequent problems he has seen is something relatively simple - poor soldering between cells. Another common issue: Electrical junction boxes on the backs of panels can come loose, possibly leading to arcing. The panel's "backsheet," a kind of film that helps keep out moisture, can crack if made from substandard materials.
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Sunrun, one of the nation's largest solar leasing companies, has found very few defective panels.