Took my PiCore setup to the local coffee shop to demo PiCore and TC.
Got my venti-latte on, started hacking, and drew a crowd when I fired up my 10" screen, RPI2, car-battery jumpstarter box, and small pure-sine-wave ac inverter. (not the cheapo msw / mod-sine inverters)
Uh yeah, that drew the ire of the hipsters.
"But look how portable it is!
...Get out of here grandpa! "
Heh, seriously - no trip to the coffee shop, but just a kick to run it off a lead-acid agm battery.
12v / 20ah vehicular jump starter box
Samlex PST-120-12 (120v ac / 12v dc) *pure* sine-wave inverter
10" screen and RPI2 draw about 1.2A on average from battery, leaving me about 8 hours of operation so as not to draw more than 50% of the sealed agm battery (bad for battery when cycling beyond 50%)