If you use a smartphone on a regular basis, you know the daily chore of searching for a power outlet or cable to charge up your phone's battery during the day. Otherwise you're probably going to find yourself with a dead battery before you get home that evening.
Companies such as Mophie, Energizer and PowerSkin make phone cases that hold an extra charge you can use to power up your phone during the day. But what if you want to charge up more than one phone? Or perhaps a phone and a tablet?
For that you need a portable external battery pack. myCharge and Innergie make portable batteries in different capacities and Jackery just released its new line of power packs.