Virtually every human being on the planet is completely reliant on electricity. In the first world, even short electricity outages cause panic. Almost everything in your house requires electricity to function, and it can be disconcerting to rely so heavily on a service that is outside of your control. Unfortunately, not many of us have the means to purchase a home and outfit it with enough solar panels to live completely off the grid. But you can at least follow these instructions to build a basic solar harvester capable of charging small devices, such as your smartphone.
Technically speaking, solar-harvesting is a broad term that covers a handful of different methods for collecting energy from the sun. You could, for instance, use special tanks to heat your water if you live in a warm, sunny area. But the more common method is to use a solar panel. Though they used to be quite expensive, solar panels have dropped dramatically in price while also becoming more efficient. The small 6V, 500mA, 3W solar panel used for this project costs a mere $3.20 (plus shipping) through AlieExpress. In addition to the solar panel itself, you’ll need a solar charging board.
That board takes the small amount of current produced by the solar panel and uses it to charge a battery, then it uses the electricity stored in the battery to charge your device. For this design, that battery is a common 18650 lithium battery. They’re affordable and readily-available, and you may even be able to upcycle one from an old battery pack. Those components are all housed within a 3D-printed enclosure. In order to use the solar harvester outdoors, you’ll need to make it waterproof. There are multiple ways to do that, but this guide recommends coating the plastic in epoxy and then sealing the two halves of the enclosure with a gasket made from liquid silicone. It won’t provide a lot of power, but this solar harvester is enough to put a bit of juice into your smartphone in an emergency.