a 150W power invertor would definitely work.
P = V*I
the charger is only outputting 2A so to hit 150W, it would have to be outputting 75V, which it won't.
i would assume that it would take roughly the same time to charge coming out of the invertor as at home since the invertor produces the same 120V AC as any plug in your house. i'd say this is a good option but a better one would be to befriend a vendor so you don't kill your car battery.
you should have come to robert randolph on friday at sphere, fun show.