I bring my own power. I have a battery more or less the size of 2 packs of cigs end to end. It has two USB charging ports so it keeps our phones powered up when we need it. It has the capacity to fully charge a cell phone 7 times before it needs to be recharged. I cant rely on maybe having an outlet or maybe having a plug that works. I'm totally ocd and have to have things i can count on.