>The first was to see how much power the Galaxy Nexus could draw from the USB connection. This turns out to be about 4.5W. (0.9A at 5V)
>Now the real test… Google Maps.
>This varied a LOT. Minimum was 4W with some steady peaks of 5.1W!
And that, folks, is how you drain a cellphone battery while it is attached to a charger.