News for hackers. Stuff that matters.

A comment on Graphene supercapacitors are 20x as powerful, can be made with a DVD burner . Parent comment

Re:Graphene supercapacitors are 20x as powerful, can be made... by kronusaturn on Monday March 19, 2012 @09:13PM (#3727284)
An iPhone battery is roughly 1400mAh at 3.7V, which gives 5.2Wh or 18720 watt-seconds. A standard power outlet in the US supplies 15A at 120V, for a maximum of 1800 watts. So if you could charge your phone using the maximum power available from a standard outlet, it would take roughly 10 seconds. A typical laptop might take about 1-2 minutes. (That's assuming 100% efficiency, which is unrealistic.)
[ Parent | on HN ]
Re:Graphene supercapacitors are 20x as powerful, can be made... by ars on Tuesday March 20, 2012 @03:13AM (#3728167)
He's talking about the wire to the battery, not from the outlet.
[ Parent | on HN ]