New Solar Charging for Backpackers

So, can I attach my solar panel to my backpack? 

For whatever reason, this is the first thought many people have when they think about solar charging on a backpacking trip. Like many things solar, the answer is “yes…but…”. Let us explain why this might not be as great of an idea as it seems.

The first issue with this charging setup is a bit more intuitive and has to do with the orientation of the trail and the terrain you’re in. Essentially, for this to work you’d need to be hiking directly away from the sun on a trail that has no interference like trees, cliffs or any other terrain that could block the sun. Furthermore, you’d need to be hiking in this constant, unobstructed trail for long enough to obtain a decent charge on your device. For sure sections of trail like this exist, but we’d say they’re the exception rather than the norm.

The second issue is far less intuitive and has to do with the way USB charging works, whether you’re at home or off on an adventure using a solar panel. While your device may appear to be charging the moment you plug it in, in reality the power source and the USB device are having a “conversation” to determine what combination of volts and amps the device needs (see picture below). This back and forth can take several seconds until the source and the device determine the ideal combination of volts/amps and charging can begin.

While this isn’t a big deal at home where the power source is consistent, if you were hiking with a solar panel the power source would (most likely) be constantly fluctuating, resulting in a never ending back and forth between your device and the solar panel. This would be the same as constantly plugging in and unplugging your device, not ideal for charging nor the health of your device’s battery.

Our advice? Unless you know you’ll be hiking in a consistent direction (with the sun at your back) through unobstructed terrain, we recommend charging when you stop. This allows for a more consistent stream of power which is not only better for charging but also better for your device’s longevity.

Charge on.