Review on 🌞 BigBlue 15W Portable Solar Charger with Dual 5V/2.1A USB, Folding Camping Solar Panels and Type-C Cable, Compatible with iPhone 11, Xs, XS Max, XR, X, 8, iPad, Samsung Galaxy, LG, and More by Anita Golladay

The product specifications state that this solar panel delivers a maximum output of 20W at 5V and 2 amps (10W) per USB port. To test this solar panel, I placed it on top of an existing solar panel at a 25 degree angle to the horizontal (see photo). I then connected the USB power meter to one of the three USB ports on the panel. The power meter was then connected to a 10,000mAh battery that was 100% dead. After 5 hours of clear and foggy sun I disconnected the battery and discharged to a steady load of 5 volts 1.0 amp. The battery delivered 11.9 watt-hours, which was 89% of what the power meter from the solar panel indicated. bottom line. This solar panel works and works well.