We just looked at Goal Zero's version two of the Sherpa 50 here at CES Unveiled 2012. At about the size of about four CD cases stacked together (and way smaller than its predecessor), this 50 watt lithium ion rechargeable battery pack powers devices on the go using its AC, DC, USB 2.0 and traditional laptop-charger ports. The pack itself charges in about four hours using a traditional outlet (and in about five hours using the solar panels) and can fully power something like a Macbook Pro, or recharge multiple cell phones. Priced at $249.99, it'll be available in June as a standalone pack, and for $400-$500 bundled with a 3-panel solar charger.