For anyone that has their battery running low while they are in the parks and has to carry a charger with them-how often are you using your phone in the parks? Do you not charge your phone overnight? Unless you have a phone with a crappy, need-to-be-replaced battery, or you constantly have your face buried in your phone screen all day, a phone that is fully charged when you wake up should last until you go to sleep that night. Using your phone outside on a sunny day at WDW is going to drain the battery quicker by requiring you to turn the brightness up all the way, but if you can hardly see the screen from the sun shining on it, why not try to save phone time for when you are inside or shaded?