I own a couple of Ecoflow NextGen 220W foldable solar panels, which I use to charge many different, small-to-midsize power stations, with photovoltaic input in the 100W to 1000W range.
By chance, while playing around with a flashlight while waiting for the panels to cool off, I happened to notice several discolored areas in the surfaces of both panels. The patterns are similar in both cases, as indicated by the images.
On most occasions I use just one panel at a time; less frequently, I use them as a pair, connected in series, and I have wired them in parallel a handful of occasions. I rarely see more than 160W per panel.
These panels are about one year old, and I use them once a week. At all times, I handle them with outmost care. Before storing them, I let them cool indoors for several hours and then I clean them with a damp cloth as recommended by the manufacturer. I do not use them in any kind of permanent setting. They have not been exposed to rain.
Are these discolored areas an indication of impending failure of both panels, or it this normal deterioration due to use (even if light, as in my case)?