At 8:15 in the video, he mentions a solar cell used while prototyping is under a "dark blue plastic box" to keep the thing from spinning out of control. There's

At 8:15 in the video, he mentions a solar cell used while prototyping is under a "dark blue plastic box" to keep the thing from spinning out of control. There's probably not too much UV getting in there. You could probably hide the cell under the base and it would go until the printed parts crumble.