You are right. Without even taking into account efficiency, “nine hours for 100 percent charge [of a 50 Whr battery] on a [5V USB] 1A power supply” obviously b

You are right. Without even taking into account efficiency, “nine hours for 100 percent charge [of a 50 Whr battery] on a [5V USB] 1A power supply” obviously breaks the conservation of energy. The claim “4.5 hours for 80% charge” breaks it even more. They should make perpetual motion devices, not external batteries.