Bests & Worsts Reviews from Amazon

The printed specifications sheet that was packaged with this "28 Watt" charger (in my case sold by BigBlue-US through Amazon Prime) stated that the maximum possible output is 5 Volt with a total of 3.4 Ampere. Firstly that information seriously differs from the information listed the PDF version of the "User Manual" that is downloadable through this product page, where the maximum output is given as 5 Volt and 4.4 Ampere. Secondly, Volt multiplied by Ampere would give us the maximum amount of Watts that this can provide, and going by the information in the printed specifications sheet we get 5 (Volts) times 3.4 (Ampere) which totals 17 (Watts). Rather far from the advertised 28 Watts. Thirdly, after I received this item a couple of days ago, I wanted of course to test it so see how well it works. Being here in Florida and it was around 1pm, I thought that this charger should be able to receive enough direct sunlight outside the house. So I spread this solar charger open on top of the trunk of my car, checked the battery level of my mobile device (it was at 80%) and plugged it into one of the USB ports. The device was turned off while it was "charging". After 10 minutes connected to this charger I disconnected it and checked the battery: it was now at 78%. So after 10 minutes connected to this device in direct sunlight, the battery has less power than at the start. Rather ridiculous.