Killer deal on Solar

+1. You absolutely cannot categorize Chinese manufactured solar modules as “cheap junk”. About 60% of all PV modules made are manufactured in China. They are used in essentially all the large scale solar installations installed in the US and are considered bankable by the institutions financing these plants, which are expected to have lifetimes of 25-30 years or longer.

There are low quality consumer products being manufactured in China and other countries of course. As always, it is caveat emptor and many products are not designed to last longer than their warranty period. Things you can llook for in solar module construction are the solar cells uniformly laid out and not touching each other, good quality fastening and sealing of output wires, delaminations or bubbles in the encapsulant, and weak or poor fitting frames. Also of course make sure the module is making power. Measure it’s open circuit voltage, short circuit current, and current into a battery at full charge. Do this on a clear day with the module directly facing the sun and compare to the specs. Don’t expect a 100 watt module to ever make 100 watts though. About 80 is more like it under real world conditions.

Yep, 1/2 percent loss of power per year is the industry standard expectation. So about 15% loss in 30 years. That's for glass front modules, don't expect that from "flexible" ones.