Martin Halloway, who is a designer of environmentally friendly buildings, decided to take down his 30-year-old solar panel to meter its performance.
It is a 33 watt Arco solar panel that he purchased in 1980. It was his first, and before he purchased it, he did not have electricity.
Apart from that, he tested it by connecting it to a 4.5 amp, 12 volt blower fan. The blower drew 2.5 amps from the panel at a voltage of 14.8 volts. That translates to 37.2 watts.
Before that, he connected a 35 watt light bulb to it, and that drew 2.015 amps at 14.93 volts (30 watts).
Halloway contacted the manufacturer to tell them, and they said it was probably due to the cool 50°F (10°C) weather. There is a temperature vs performance curve for solar panels. As temperature decreases, solar panel performance increases.
Solar panels normally last 30 years. Their lifespan range is 20 to 40 years. Solar panel warranties are usually 20-25 years, and, like product warranties in general, tend to be a little shorter than their average lifespan (otherwise manufacturers would have to replace most people’s solar panels for free, which would not be feasible).
This is why warranties are so important. Always check warranties — they carry a lot of weight if the manufacturer is financially sound and expected to stick around for a long time.
Solar Panels Perform Best when Cool
Heat reduces the efficiency at which solar panels operate, and therefore reduces their power output. It causes the production of less electricity per unit of sunlight that hits the panel.
Fortunately, this helps to compensate for the lack of sunlight during winter.
Solar panels are semiconductor electronics, and semiconductor electronics in general are best off cool. They are most reliable and efficient when cool.
Still, 30 years and still performing at factory specs is something worth noting.
Source: Renewable Energy World