I’m only half kidding. I’m a bit of a prepper and I have lots of powerbanks and devices that charge from USB but besides idling my truck I really had no other way to charge any of them in case of a long-term power outage which seemed a bit of an oversight on my part.
Not like this solves the issue. 30 watts (under ideal conditions) isn’t much but it’s a start.
Highly doubtful. ~30% efficiency is already pushing the limit of solar panels. No way you’d get over 65%.
Efficiency means how much of the sunlight hitting the panels gets converted into electricity. How accurately manufacturers report the true output of the panel is a completely different thing. Plenty of reputable brands reach the advertised output.