Why are they so light? Do they way less than high rated 18650 cells would be for the rated capacity? If so they are probably inflating the rating. As is shockingly common for no name powerbanks. There are very minimal usb boards you can load 18650s into, or attach quad copter cells to, 3d print your own minimal case that suits your needs with the highest capacity and quality cells you can afford.
Why are they so light? Do they way less than high rated 18650 cells would be for the rated capacity? If so they are probably inflating the rating. As is shockingly common for no name powerbanks. There are very minimal usb boards you can load 18650s into, or attach quad copter cells to, 3d print your own minimal case that suits your needs with the highest capacity and quality cells you can afford.