I'm looking for the best possible option to power this screen: http://www.cartft.com/catalog/il/527

I've thought of getting this Tekkeon battery: http://www.tekkeon.com/site/products-mypowerall.php

I know that battery will last us about 4 hours and needs 5 hours to charge and can just be plugged into the screen's DC connector, but I'm looking for something just as easy that'll last longer than that. I'm also wondering if this battery is worth its price, this one: http://www.gps-store.nl/index.php?main_page=product_info&products_id=922 seems to do exactly the same at a far lower price but it doesn't seem to have the right connector for our screen.

Any advice will be much appreciated, thx!

the second one will not work , output is only 5.5V
this kind of screen is 12V, about 0.8Amp (let's say 1Amps).
any li-ion pack between 12 an 14V rated 8 amps, will give you about 8 hours.
8 amps is a lot for battery pack, but you can find or build one at www.batteryspace.com