Solar Powered Phone Chargers

David Wilczynski
December 7, 2015

Submitted as coursework for PH240, Stanford University, Fall 2015

Introduction

Fig. 1: Are solar powered chargers a way of the future? (Source: Wikimedia Commons)

Our world today has evolved from the initial energy components that came from sources such as coal, petroleum, and other fossil fuels. These resources were found to be very harmful to the environment and not as efficient as they could be. Fossil fuels emit damaging carbon dioxide, nitrogen dioxide, and carbon monoxide emissions into the atmosphere. These fuels, when burned and released into the air, are known to be one of the primary causes of global warming. With the Earth's ozone layer depleting and global climate change very much affecting our lives today, we constantly are turning to unique forms of energy that will be greener for our environment. One of these energy alternatives come through harnessing solar powered energy.

How Solar Energy Works

Plain and simple, solar energy comes from the sun. Whenever the sun is shining, it is radiating heat down to the Earth and any object exposed to the sun contains heat energy. And what's amazing about solar energy is that it does not give off any of those harmful discharges and there's an unlimited amount of it. One of the problems associated with solar energy, though, is that all the heat energy radiated towards the planet is not attracted to one specific spot; the heat is spread over the Earth's surface. [1] To use this energy efficiently, the heat must be drawn to one precise area instead so that it can be harnessed from direct sunlight into energy. One way to do this is using a solar cell that takes this sunlight and converts it into electricity. In a solar cell, the light get absorbed and an electron that is in one of the bonds gets excited to a higher energy level which makes it move more freely than when it was previously bonded. [2] In solar panels, each solar cell (also known as photovoltaic cell) is made up of silicon and the sunlight knocks an electron free, pushing that electron out of the silicon junction. [2]

Harnessing Solar Energy into Phone Chargers

Solar power is a relatively new concept, and just recently have we started to discover the potential that it has. Utilizing this type of energy for electricity is only one small example of its uses. Converting solar power to charge a phone is another, and this is where things start to really get interesting. Imagine not having to charge your phone using an electric outlet but rather being able to harness the sun's power to boost your phone's charge. This idea is marvelous! You would save money by not using electricity, you would be efficiently using energy, and you would only have to rely on finding the sun rather than finding an outlet. This concept is possible and has already begun to manifest itself in the world of phone chargers today. Let's take a look at the materials needed to create this device. Pretty much all you need is the right connectors, the right amperage and voltage of the device, and a battery to store the energy that the solar panels collect. [3] In the conversion process, photons knock electrons loose from atoms, and this is the subatomic energy packet that forms the basis for light. Next, photons from the sunlight carry enough energy to jar electrons from their orbit in the element silicon, which is the material used in most solar cells. Finally, this solar power recharges a battery by reversing the flow of the electrons, replenishing the battery's electrical potential. [3] Although some of these chargers may be a little bit pricey, others provide a deal that ultimately saves consumers lots of money. With charge time around ten hours, you can leave these chargers on a windowsill, and some chargers are even coming built into phone cases now. One of the most standard types of solar powered chargers is shown in the figure (at the top of the page). This includes a solar powered cell that connects through a wire to the phone.

Conclusion

As solar powered energy becomes increasingly popular, these phone chargers will rise in popularity as well. Because people are searching for new and improved forms of energy, solar energy is becoming a very appreciated idea. Fossil fuels and non-renewable energy sources are ways of the past. This is the way of the future. Solar powered phone chargers will soon be everywhere.

© David Wilczynski. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.

References

[1] S. Locke, "How Does Solar Energy Work?" Scientific American, 20 Oct 08.

[2] G. N. Tiwari and M. K. Ghosal, Renewable Energy Resources: Basic Principles and Applications (Alpha Science International, 2006).

[3] R. Z. Arndt, "The Solar-Powered Phone Charger That Actually Works" Popular Mechanics, 29 Oct 15.