Smartphones and other electronic devices have become commonplace in the backcountry. There are incredible advantages to having a high quality camera, GPS unit, music player, guidebook, and emergency phone all in one lightweight item. Besides smartphones, there are additional types of electronics in the field, such as rechargeable headlamps and eReaders. But even the best electronic gadget isn’t worth anything without power, which is where portable power devices become essential.
External batteries are charged up before you leave home and hold a certain capacity of power. There are two BIG advantages to using a battery -- they are reliable even on cloudy days and they are small and compact. With a battery pack, all you need to do is plug in your device and it will charge up within a few hours.
Capacity varies from 2400 mAh (about 1 phone charge) to over 20,000 mAh. Bigger batteries come with more capacity but also have more weight.
Batteries are my portable power of choice for shorter trips (<5 days) or for longer trips with minimal power usage. Even long distance hikers are using battery packs since they can visit a town every week or two for a recharge. Battery packs are becoming the most common option for portable power due to their low cost and high versatility.
As trips get longer and more remote, solar panels become more appealing because you have an infinite power source -- the sun. The trick with solar panels is to balance power output (watts) against weight. Arrays with multiple or bigger panels will give you more wattage but are also heavier. To make things even more confusing, some panels come with built in batteries that store charge, while others require you to have a device plugged in while sitting in the sun in order to charge.
The best solar panel for your needs is primarily dependent on how abundant the sun is, ie. California desert vs Pacific Northwest. If you are traveling in a cloudy environment then a larger array and higher output will be required. If you are traveling in a sunny environment you could get by with a smaller array that charges a battery. Paddlers and basecampers can opt for a larger array since they don’t have to worry about weight.
Overall, a solar panel is the way to go for long and remote backpacking or paddling trips. The array weighs more than an external battery but provides you with unlimited power (assuming conditions are appropriate).
Here a great example of a solar panel set up for a paddling trip.
