I received mine last Friday, along with a note saying that my order was "upgraded" from a 300W to a 150W. How is that an upgrade? Unfortunately, I didn't discover this until after I had thrown out all of the packaging, so I"m not sure exactly what I got. I wanted this to power a laptop on long driving trips, but I don't know if the 150W is powerful enough to do that. Anyone else have this experience?