My iPhone battery runs low all the time. It is especially frustrating when I travel and am not near an outlet to recharge it. I have found the perfect solution, a portable charger about the size of a large tube of lipstick. In minutes it will get you out of the red, and in about an hour it will fully charge your phone. It will hold enough power to charge your phone about 2 and Yz times. The one I have is made by Anker and is called the Anker Astro Mini 3000Ah Ultra- Compact Portable Lipstick-Sized External Battery Backup Charger. The name is larger than the backup device! I bought mine on Amazon for $22. There are many other makes and models of the same type of portable charger.
Some are larger and hold more of a charge. But, for traveling, I recommend this small unit that gets you from one outlet to another with no fuss. ■