Martin Halloway, a green building designer, had been living without electricity for five years before he purchased his first solar panel in 1980. This exact module, an Arco Solar 16-2000, 33-watt solar panel, was manufactured in 1979 and continues to produce power today.
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A couple of years ago, Halloway decided to bring the solar panel down from his roof after 30 years and test it out. It was an unusually crisp, clear day of about 50 degrees Fahrenheit.
Halloway’s solar panel was designed for a 12-Volt battery (Max. Voltage of 16VDC), so he tested the module by connecting it directly to 12-Volt loads.
Halloway’s first test was connecting a 35 Watt, 12 Volt incandescent light bulb. The light bulb lit up, passing test number one.
Halloway says that his Fluke multimeter showed the voltage of the module at 14.93 Volts with a full load of 2.015 amps.
Next, Halloway connected the Arco Solar Panel to a 4.5 amp, 12 Volt blower. The blower drew a full 2.5 amps from the thirty-year-old module, which is actually higher than the module’s factory specifications.
When Halloway called up the manufacturer to share the exciting news, they were surprised but explained how this was probably due to the cool weather during this test. The cooler temperature must have made for a 10% increase in performance.
Warranties generally cover a solar module for up to 25 years at 80% nominal output. To be considered effective by most manufacturers, a solar panel has to operate at least 80% of its rated peak output. So even when some older modules may not reach that 80% mark of the rated peak output, they can continue to produce smaller amounts of energy for years after their warranties are up.
This Arco solar panel, however, far outlived its warranty and is certainly working well into its old age.
With the improvements to solar panels since 1979, how long into the future will some of today’s solar panels be functional?