An external battery pack/charger like the Jackery will extend the use of your smart phone and other devices. I started toting one a couple of weeks ago after seeing another cyclist using one during a group ride. Works with my iPhone, Ion Speed Pro video camera, and USB rechargeable bike lights. The only tricky bit is remembering to click the on/battery check button once after hooking up the cable.

I use a couple of Lowepro lens pouches Velcro'd across my handlebar to hold the battery pack and other devices I want to keep handy. The charger cable snakes through the bag with the zipper nearly fully closed. As long as it isn't raining it's fine to run while riding. If the weather looks bad I'll use the weatherproof seal on the back of the Ion Speed Pro, and put the phone, battery pack, etc., into ziplock bags. I can still operate the phone touch screen through a ziplock bag.