Yeah, maybe it was a red herring (a black-body herring?) to bring up batteries here. The solar panel itself is already non-reversible, and so is the arc welder

Yeah, maybe it was a red herring (a black-body herring?) to bring up batteries here. The solar panel itself is already non-reversible, and so is the arc welder, right? That seems to be the important difference from the lens. In that sense, we don't run either of them "for free" in the way that the xkcd piece describes.