Cell Phone- Battery Pack-Charger

[Ironhorse]

Looking for some input from those much more hi-tech than myself to recommend a good small, portable, rechargeable cell phone battery pack for use when wandering thru car shows, swap meets and similar events where one can't plug into a 120volt receptacle. Any input as to which ones are good and which ones are junk would be appreciated.

Have a two day swap meet I will be setting up at with no available 120 volt receptacles. Can charge cell phone overnight and in the truck heading out but once I get to my booth there is nothing to charge from.