Car chargersA convenient option for vacationers spending a lot of time at the wheel, car chargers fit into a car's cigarette lighter and users can take advantage of the drive to charge their device. With prices starting at around US$5, car chargers are efficient and easy to use. When purchasing one not made by the phone manufacturer (Samsung, HTC, Blackberry, etc.), pay close attention to compatibility. Not all car chargers work with the iPhone, for example. Recharging on the road is even simpler when your vehicle is equipped with a USB port: no need to buy a charger, just plug in the USB cable that comes with most smartphones.
Solar chargersFor the environmentally conscious, there are solutions for recharging your phone with little to no carbon footprint. The solar option frees smartphone users from the necessity of finding a power outlet as long as there is access to the sun's rays. The Waka Waka Power charger, for example, recently hit the market thanks to Kickstarter funding and is now available for US$79.
Wind-up chargersFor those looking for an environmentally-friendly charger that doesn't depend on the weather -- sunny or not -- wind-up chargers are a good bet. You may have to put in a little physical effort, but you'll have peace of mind in knowing you can recharge in any situation. In this vein, the Eton dynamo charger is available at around US$80.
External batteriesFinally, there is always the option of hooking up to a back-up battery. Usually equipped with multiple USB ports, external batteries give a phone a boost when the internal battery gives out. Their main advantage is that they can enable long stretches of use without charging. On the other hand, they can be inconvenient to carry around and add extra weight and bulk to your phone. The brand Anker offers models starting at about US$40. For phones with removable batteries, it is also possible to carry a pre-charged spare, which is lighter than an external one and is ready to be slipped into place.