Hot spots can stem from overshadowing, dirt or microcracks. When the sunlight hits solar cells, it is supposed to be converted into electricity. However, if the resistance of one solar cell rises, this part of the panel heats up. This is the hot spot – overproportional heating of one cell compared to the others.
You can detect an emerging hot spot with an infrared camera only. Eventually, hot spots in solar panels become visible to the eye: the problematic cell becomes brownish.
Hot spots lead to a faster solar panel degradation and can even start a fire on your roof. To avoid that, clean your panels from dirt every now and then. Before the installation, carefully pick a place without any shade. If some shading is unavoidable, opt for panels with a high shading tolerance and bypass diodes, like Panasonic HIT 330W
or REC 365W Alpha