Review on 🌞 KINGSOLAR 21W Portable Solar Charger: Waterproof, Foldable Solar Panel Charger with 2 USB Ports for Camping, Cell Phone, Tablet, GPS, iPhone, iPad, Camera & More by Jeff Bundrick

Port 2.5 doesn't seem to work or I don't understand something. When I plug some of these in, the charging indicator just flickers, but when I plug the same into the 2.1 port, it charges. Charging is very slow, so fast charging is not possible with this solar panel, which is a shame. However, it does charge the device, it only takes about 6 hours to charge a Samsung S10+ that is in flight mode and not in use.