Design of a Solar Handheld-Device Charger

Abstract

This report documents the design and development of an affordable, appealing and well-performing solar handheld-device charger (the Solution), which fits the needs of the targeted users, who live in developing countries, have no or only limited access to electricity, but can afford to, and have the aspiration to own a mobile phone. The assignment was provided by Lemnis Solar, a start-up company that develops and sells high quality solar products focused on emerging markets, especially in Southern Africa, where having no access to electricity is still part of people’s daily life. Many people worldwide still have no safe and reliable access to the electrical grid. Africa has one of the biggest non-electrified populations, which is expected to grow even bigger in the coming years. Moreover, the off-grid population is not the only market for alternative power sources; households with unreliable grid connections are in need of additional solutions as well. Lack of access or limited access to electricity is a general problem in many African countries. Mobile phones can improve people’s lives in developing countries significantly, and are becoming increasingly common among the poor in Africa because of their affordability. However, due to the continent’s low electrification, millions of mobile phone users are in need for alternative phone charging solutions, and their number is predicted to grow in the future because the pace of electrification of the continent cannot keep up with the growing population and the growing number of mobile phone owners. Solar technology is a promising solution for mobile phone charging, which is already becoming increasingly popular in Africa. To simplify the process of defining the user needs, South Africa was selected as the focus of this project, where the major relevant problems are existent as well. It was found that the most popular phones are cheap and basic, or slightly more advanced, but still low cost models. The variety of phones is diverse; and a solar charger will need to be compatible with all of them. Several solutions are used by those who have no access to electricity to charge their phones. However, the majority of them are unaffordable, inconvenient and unsafe. Personas were created; and based on their needs, the design direction for developing a suitable solar charger was defined. The direction, a portable versatile solution is a smaller scale product that can be used in various conditions and locations. It focuses on mobile-device charging, and is powerful enough to be a satisfactory phone charging solution on its own. Its portability and versatility makes it a suitable product in a variety of scenarios. This solution is needed by those who have no access to convenient and cheap methods to charge their phones and by those who need a reliable and flexible back-up solution. There is a big variety of solar chargers on the market. However, the majority does not fit the needs of the target group. Their main problems are that they do not have the right performance, which was specified based on the analysis of solar, and battery technologies, and price, which was found to be too high for the target group. The functions of the Solutions were defined: harvesting energy by converting solar radiation into electricity (charging), storing the harvested electricity and releasing the harvested electricity and charging electronic devices with it (discharging). Moreover the main criteria that it has to meet in order to satisfy the needs of the target group were specified: affordability, portability versatility, durability, clarity, good performance, safety and attractive appearance. Based on these design guidelines, concepts were formulated. The best two concepts were prototyped, and tested as part of a field research, which was conducted in Zimbabwe, to gain knowledge about how the concepts could be improved, and which one should be chosen to be the basis of the final design of the Solution. The research consisted of product testing, observations and interviews. The results of the field research were used to create the final design proposal. The result of the project, the Solution is a portable, versatile and affordable solar handheld-device charger, which provides a safe, reliable and convenient charging solution. It charges all mobile phones and a wide variety of battery powered devices. It is equipped with an internal battery, which stores enough energy to charge a basic mobile phone completely. The internal battery can be charged by solar power in only one sunny day, and it can also be charged from the AC power grid. It is simple and easy to use, and can be operated with only one button. It is equipped with a LED indicator to show how much power is left in its battery. The Solution comes in an aesthetic protective case, which can be used as a stand to ensure that its solar panel is in the right position in any circumstances.