Review on Solar-Powered Mini Exhaust Fan, WdWkrTools 10W 12V, for Ventilation in Camping, RV, Chicken Coop, Dog House, Greenhouse, Shed Roofs, Tree House – Quiet Operation with Sunlight Requirements by Norman Costello

Well this Wdwkrtools fan works but the solar panel needs to be in direct sunlight or it's not powerful enough to even turn it on. If there's a cloud around, forget it. With all the extra accessories, I was able to run the fan from a battery or a USB wall adapter, but it ran much slower than with a panel in direct sunlight. The solar panel indicator glows in indirect light as if you were indoors and standing by a window, but when a fan is connected it doesn't glow at all. In general, the airflow you get from a fan is actually quite small. Unless you're already in a cool environment, you won't get much relief from this. If you use it to draw air, it will do so very slowly.