Battery life is the bane of every cellphone's existence. It is a major bullet point on every new phone's release and often a common complaint of even the happiest owners. Many products are out there that can extend the battery life of your device, or even charge it on the go. In this tutorial, you can learn how to make your own multi-port usb charger that is solar powered.
This tutorial is meant for people who are more toward the beginner side of the scale, so you'll note that they don't create any of their own circuits. It is a great guide however, even if you are experienced, on how to create a very useful tool without much effort.
To build this, you'll need a powered USB hub, solar panels of your choice, a charging circuit, and a battery to keep the charge. A quick example is shown using a large 5V 700mAh panel with a single USB charging port. This example is primarily just shown as a prototype; it looks like it would be awkward to tote around.
The bulk of the tutorial shows the construction of a more compact unit with two 2V panels running the power. The main modification to the powered USB hub is simply patching the output from the battery into the power circuit, noting that the power LED should be removed to avoid slowly draining the battery. After that it is more like a game of Circuit-Tetris trying to fit the pieces together into a nice, portable, and enclosed unit.
As you can see, the final result above is fairly aesthetically pleasing and functional, though I personally would have probably removed the purple LEDs as well just to avoid unnecessary power drain.
— Caleb Kraft, Chief Community Editor, EE Times