Pneumatic Physics: The invisible 14.7 lbs of force holding your flexible panels to the roof

If you don't want to permanently glue your EcoFlow 100W Flexible Solar Panels to your vehicle, you likely use the specialized suction cup mounts. But how do simple rubber cups survive 70 mph highway winds without tearing off? It all comes down to Pneumatic Physics and atmospheric pressure.

A suction cup doesn't actually "pull" on the fiberglass roof. When you press the cup down, you physically force the air molecules out from underneath it, creating a localized vacuum. The Earth’s atmosphere pushes down on everything at approximately 14.7 pounds per square inch (psi) at sea level.

Because there is no longer any air underneath the cup to push back, the absolute weight of the Earth's atmosphere physically crushes the rubber down against the roof. A single perfectly sealed 2-inch suction cup is held down by nearly 45 pounds of atmospheric weight.