EVDV was supposed to be the answer (2005) but its dead
http://www.engadget.com/2005/03/06/e...h-kills-ev-dv/
Turns out no one cares (much) about it.
Your wifi should work while talking, but then you'll need to fire up your Gasoline battery backup generator - I'm thinking you've got 2 hours max battery in that mode....