I use the solio classic and like it very much. A few reasons I think one should have an alternative charger like the solio is that when a large scale event happens such as the Hatti earthquake the first line of comunication to come back up were cell towers and the few who had power were charging for minutes at a time to recharge cell phones. Secondly the solio can charge other small devices(i.e.... camera, gps).

Another feature i like about the solio classic is the storage time it can hold a charge for up to 3 years according to manufacture, and multiple charging methods of the charger itself from car out let, wall socket and solar.

I purchased mine from the manufacture on a closeout deal for like $49 This is the link to the closeout section. http://store.solio.com/s.nl;jsessionid=0a0105501f43c67ebdf62b494ff4b8da88947270389f.e3eSc34OaxmTe34Pa38Ta38Tbhz0?sc=7&category=2596