Traveling can put some heat on your cell phone batteries. Nice phones have nice camera’s. It’s very convenient and after a hundred snaps, plus using the GPS and maps to find your way around. Your battery get’s drained quickly. So if you need a quick jump, you can use a 9V battery to recharge you quick and easy. You probably cannot get a full charge out of an entire 9V. But it will get you some much needed juice. And it’ll cost ya a couple of bucks.
And, if you get the right one, you can put your charger in one pocket and your phone in another, charge on the go. And, if you want… you can make it yourself. Probably a little easier to carry around like this.