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UNIVERSITY OF EDUCATION, WINNEBA
COLLEGE OF TECHNOLOGY EDUCATION, KUMASI
DESIGN AND CONSTRUCTION OF A SOLAR CELL PHONE CHARGER
WITH BATTERY BANK
CHARLES KUDJO ADDO
AUGUST, 2017
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UNIVERSITY OF EDUCATION, WINNEBA
COLLEGE OF TECHNOLOGY EDUCATION, KUMASI
DESIGN AND CONSTRUCTION OF A SOLAR CELL PHONE CHARGER
WITH BATTERY BANK
CHARLES KUDJO ADDO
(7151200003)
A Dissertation in the Department of ELECTRICAL AND AUTOMOTIVE
TECHNOLOGY EDUCATION submitted to the School of Graduate Studies,
University of Education, Winneba in partial fulfilment of the requirements for the
award of Master of Technology (Electricals/Electronics) degree
AUGUST, 2017 ii
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DECLARATION
STUDENT’S DECLARATION
I, CHARLES KUDJO ADDO, hereby declare that this dissertation, with the exception of sources which have been cited and duly acknowledged, is entirely my own original work. To the best of my knowledge, it has not been previously submitted either in part or in whole for the award of any degree elsewhere.
SIGNATURE: ………………….……………………
DATE:………………….….…………………………
SUPERVISOR’S DECLARATION
I hereby declare that the preparation and presentation of this dissertation was supervised in accordance with the guidelines for supervision of thesis as laid down by the University of Education, Winneba.
NAME OF SUPERVISOR: PROF. W. OFOSU
SIGNATURE: ………………….……………………
DATE:………………….….…………………………
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ACKNOWLEDGEMENT
I did not know that the Lord will favour me this way, I thank you Jesus. I am grateful to
God Almighty for giving me the strength and knowledge to carry out this research.
I would also like to thank my supervisor, Prof. W. Ofosu, for his advice, guidance and patience exhibited towards me.
I am grateful to my family, my wife, Mrs Rose-Evelyn Addo and my children for their love, encouragement and support. I would like to acknowledge my class members – M
Tech Electricals / Electronics Technology (2017); for you have been wonderful and very supportive. I am highly indebted to all lecturers of UEW – Kumasi, the
Electricals/Electronics Technology Department especially Dr. Albert Awoponi for his immense contributions.
Also, I am grateful to the head of Electrical Department, Kumasi Technical Institute,
Madam Banini Acolatse for her advice.
Additionally, I am thankful to all the authors whose works were cited. I duly acknowledge them with great respect and gratitude.
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DEDICATION
This dissertation is dedicated to the Almighty God who has seen me through my education up to this level. Also, I dedicate it to my parents, Mr. Eric Addo and Mrs
Comfort Addo as well as my wife and my children, Christian and Christopher for their support, inspiration and encouragement to pursue and finish this course successfully.
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TABLE OF CONTENTS
CONTENT PAGE
DECLARATION ii
ACKNOWLEDGEMENT iii
DEDICATION iv
TABLE OF CONTENTS v
LIST OF TABLES ix
LIST OF FIGURES x
ABSTRACT xii
CHAPTER ONE
INTRODUCTION
1.1 Background to the Study 1
1.2 Statement of the Problem 3
1.3 Purpose and Objectives of the Study 4
1.4 Objectives 5
1.5 Significance of the Study 5
1.6 Limitations 6
1.7 Delimitations 6
1.8 Organization of the Study 7
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CHAPTER TWO
RELEVANT LITERATURE REVIEW
2.0 Introduction 8
2.1 Overview of Renewable Energy Resources 8
2.2 Historical Background of Solar Cells 10
2.3 Solar Energy Resource in Ghana and the Renewable Energy Act 11
2.4 Solar Energy and its Sources 12
2.5 Solar Energy Process 14
2.6 Theory of Solar Cells 15
2.7 Solar Photovoltaic Technology and Principle 16
2.8 Efficiencies of Solar Panels 18
2.9 Benefits of Solar Battery Chargers 18
CHAPTER THREE
METHODOLOGY AND CONSTRUCTION
3.0 Introduction 20
3.1 Methodology 20
3.2 Construction of the Solar Panel 21
3.3 Block Diagram of the System 21
3.4 Solar Mobile Phone Charger Circuit 21
3.5 Circuit Operation 21
3.6 Function of the Components Used 23
3.7 List of Components used for the Construction of the Solar Mobile Charger 24
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3.8 Construction Procedure and Testing 25
3.9 Testing of System Operation 27
3.10 Problem Encountered 28
3.11 Cost Analysis 28
CHAPTER FOUR
RESULTS AND ANALYSIS
4.0 Introduction 29
4.1 Discussion of the Results of the Experiments 29
4.2 Charging Current and Voltage of the Solar Mobile Charger Constructed 29
4.3 Charging Duration for the Solar Mobile Charger with Battery Bank to
Fully Charge a Mobile Phone (Samsung Android) with 1300mAh Battery
Capacity 30
4.4 Charging Current and Voltage of the Battery Bank Alone in the of Solar
Mobile Charger 32
4.5 Charging Time of Samsung Android Mobile Phone Using the Battery
Bank Alone in the Solar Mobile Charger 34
4.6 Charging Time of a Conventional (AC) Charger 37
CHAPTER FIVE
SUMMARY OF FINDINGS, CONCLUSIONS AND RECOMMENDATIONS
5.0 Introduction 39
5.1 Summary of the Findings 39
5.2 Conclusion 40 vii
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5.3 Recommendations 41
5.4 Suggestions for Further Research 41
REFERENCES 42
APPENDICES 49
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LIST OF TABLES
TABLE PAGE
Table 3.1: Cost Analysis of the Unit Constructed 28
Table 4.1: Charging Time for Samsung Android Mobile Phone Using Solar
Mobile Charger with a Battery Bank 31
Table 4.2: Charging Time of Samsung Android Mobile Phone Using the Battery
Bank Alone in the Solar Mobile Charger 34
Table 4.3: Charging Time of Samsung Android Mobile Phone Using
Conventional Charger 37
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LIST OF FIGURES
FIGURE PAGE
Figure 3.1: Solar Panel Used 21
Figure 3.2: Block Diagram of the System 21
Figure 3.3: Solar Cell Phone Charger Circuit Diagram 22
Figure 3.4: Interior connections to the solar panel (back view of the panel) 26
Figure 3.5: Connections of some components on Printed Circuit Board (PCB) 26
Figure 3.6: Interior components of the unit in fixed positions 27
Figure 4.1: Connection of the D.C Ammeter (0 – 1A) to the Solar Mobile Charger 30
Figure 4.2: Connection of the D.C Voltmeter (0 – 10v) to the Solar Mobile Charger 30
Figure 4.3: Charging Time for Samsung Android Mobile Phone Using Solar
Mobile Charger with a Battery Bank 31
Figure 4.4: Connection of Samsung Android mobile phone to the solar mobile
charger 32
Figure 4.5: Measuring the charging current of the battery bank of the solar mobile Charger using a D.C Ammeter 33
Figure 4.6: Measuring charging current of the battery bank of the solar mobile
Charger using D.C Voltmeter. 33
Figure 4.7: Charging Time of Samsung Android Mobile Phone Using the Battery
Bank Alone in the Solar Mobile Charger 35
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Figure 4.8: Connection of the D.C Ammeter (0 -1A) to measure the conventional
charging current 36
Figure 4.9: Connection of the D.C voltmeter (0 – 10v) to measure the conventional
charging voltage 36
Figure 4.10: Charging Time of Samsung Android Mobile Phone Using
Conventional Charger 38
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ABSTRACT
This study focuses on the design and construction of a solar cell phone charger with battery bank. It is designed to meet up with the high demand of power supply needed to keep our cell phone batteries charged especially people in open public places like traders in Kejetia market in the Ashanti region of Ghana. A solar cell phone battery charger is an electrical device that converts the energy of sunlight directly into electricity by the photovoltaic effect. It does this by the use of photoelectric cell which when exposed to light, can generate and support an electric current without being attached to any external voltage source. This work is aimed at constructing a solar cell phone battery charger system with battery bank which receives 10V DC from the solar panel and converts it to the level that can be safe use to charge cell phone batteries. Based on the objective of the study, data was collected and analysed. A phone with battery capacity not exceeding
1300mAh was chosen and retested to ascertain its current level, voltage and other electrical complementary demand. The test was done using voltmeter and ammeter. After careful determination of the various capacities of the various components, the unit was then constructed taking into consideration a number of factors. The construction of this portable cell phone charger will therefore help the people in open public places where there is availability of sunlight to charge their cell phones.
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CHAPTER ONE
INTRODUCTION
This chapter presents the introduction and the background of the study. It also discusses the statement of the problem, purpose and objectives of the study as well as the hypothesis on which the research was based. It further highlights the significance of the study, limitations and delimitations are also captured in this chapter. Finally, the organization of the study is also presented in this chapter.
1.1 Background to the Study
Through the Renewable Energy Act (832) enacted in 2011, the government of
Ghana has developed a policy plan to vigorously increase the share of renewable energy sources in the generation mix to 10% by the year 2020 (Acquah, Ahiataku and Ashie,
2017 & Boateng, 2016). In accordance with the policy, the Ghana Energy Development and Access Project (GEDAP) under the Ministry of Energy (MoE) have undertaken the goal to deploy solar photovoltaic mini-grid systems to supply electricity to the rural island communities on the Volta Lake (Boateng, 2016). Given the current energy crisis and increasing need for sustainable energy, this research endeavors to create a cost- effective, small-scale electric generator which can be used to power consumer electronics. Solar energy has proven its worth as an alternative energy source because it has low-impact? And is emission-free (emission of what?). It has been implemented with much success for power grids with hundreds of acres of enormous solar concentrators.
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On the small-scale, solar energy has been harvested through the use of photovoltaic (PV) panels and have been used to power anything from a phone to residential homes. Although PV cells are considered as part of the green energy revolution, some materials utilized for its construction are extremely dangerous to the environment and therefore, much care must be taken to ensure that they are recycled properly. PV cells also only utilize the energy stored in specific wavelengths of light and therefore have an approximate efficiency between 14-19% according Boateng (2016).
Sunlight, however, produces immense amounts of heat which only serves to heat up the surface of the solar cell. Although there are some PV cells that have reached efficiency levels over 40% (the world record is 41.6%), they are enormously complex and expensive (Acquahet, al., 2017). The concentrated solar power (CSP) works differently because it focuses solar energy in it’s entirely? rather than absorb it. Ultimately, this project will be designed, and produce a solar powered battery charger.
A solar cell phone battery charger is an alternative to conventional electrical cell phone charger and in some cases can be plugged into an electrical outlet. Amankwah-
Amoako (2015) expounds that there are also public solar chargers for mobile phones which can be installed permanently in public places such as streets, parks and squares.
Some models of cell phones have a built-in solar charger and these are commercially available for GSM cell phone models (Amankwah-Amoako, 2015). Solar cell phone chargers come in different shapes and configurations including folding and rotating types.
They also come in the form of straps, with solar cells on the outer surface and a nickel metal hydride battery within. They are capable of charging mobile devices fully within six hours of exposure to the sun resulting in 40 minutes of talk time (Belmonte, Escalante
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& Franco, 2015). Solar chargers are also available for other cell phone accessories, such as Bluetooth headsets and speaker phones.
1.2 Statement of the Problem
Cell phones have become an extremely popular device in the entire world and it is easy to say they are part of our daily lives. In the year 2010 there was an estimate of over
4.6 billion cell phones worldwide and the number has been growing by more than a billion ever since; this translates to more than half the world’s population (Donner, 2012).
Both the developed and the developing world countries are buying more cell phones, but it is in developing countries where the cell phone growth stays the strongest (Donner,
2007). However, cell phones need electric sources to charge their batteries in order to work, but there are people in developing and third world countries that find it hard to access electric sources due to one challenge or the other.
Obviously, conventional mobile phone charging systems are made available in homes, offices and public places, yet in Ghana, there are other open places or markets which do not have access to conventional charging systems. The researcher’s trip to
Kejetia and Central markets as well as other commercial places in the Ashanti region of
Ghana revealed that traders find it a challenge in charging their mobile phones while working as traders. Therefore, an alternative mobile phone charging system would be of great help. This consequently inspired the need to design and build a solar powered charging system that can serve as an alternative cell phone charger for people in such places.
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However, even though solar mobile chargers have a lot of benefits such as emission free, they still have some challenges. The most obvious of these challenges of course is that during the night, a solar powered charger will not to be able to harvest the energy it needs from the sun in order to function.
The other challenges with this system are as follows:
Cost: One of the main drawbacks of solar power is the cost of its installation.
Reliability: Due to the fact that solar chargers have no capacity to store the energy collected during the day, they are only useful for a small period of time. Even as the sun goes down, the power gained will start to plummet.
Time: Solar powered chargers take a while to restore the majority of the battery in a cell phone or navigation system, and, as they only work during the day, this will involve having to stop, set up the system and then wait for it to charge, which may not be ideal in your some situations.
Practicality: Taking a cell phone with you on a trip may be necessary as an emergency measure. As solar chargers only work during the day and take time to charge up, a cell phone may no longer seem like a practical emergency communication means.
1.3 Purpose and Objectives of the Study
Generally, every research work is conducted to find out pertinent issues that affect people. In this regard, the purpose of this study is to design and construct a solar charging device for traders at public open places such as markets to help charge their mobile phones while they trade all day.
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It will also provide consistent electricity supply or portable solar power charging systems for those who travel a lot (with or without battery) to power their mobile phones to enable them make and receive calls.
1.4 Objectives
i. To design and construct a solar cell phone charger with battery bank.
ii. To analyse the cost of building solar powered charger and compare it to the price
of foreign ones.
1.5 Significance of the Study
The product of the design will help;
i. traders at markets (e.g. Kejetia) charge their phones and reduce the challenges
traders face whenever they want to charge their phones from other source.
ii. eliminates the cost of charging mobile phones at conventional phone charging
businesses. iii. traders to own their own solar charger.
There are several advantages that can be enjoyed when using a solar charger instead of a conventional phone charger. Energy is saved by solar usage unlike conventional energy that produces a lot of waste emissions during its generation. Energy to power a solar cell phone charger is drawn from renewable sources and produces no waste. A solar phone charger, can be carried anywhere, provided there is an access to solar energy.
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The most important benefits that solar cell phone battery chargers provide includes:
i. They do not have to depend only on the conventional (AC) charger to recharge
their cell phone batteries. This means that solar battery chargers depend on the
sun which is available anywhere.
ii. Solar cells generate no emissions, waste or by-products.
1.6 Limitations
In the course of carrying out the study, the researcher faced these challenges;
Firstly, combining learning with research for the dissertation did not allow for adequate time to gather more comprehensive data.
Also, the researcher during the construction of the device suffered some noticeable drawbacks which include mechanical problems: difficulty in installing all external components, albeit, this difficulty was overcome.
1.7 Delimitations
Although, there were some drawbacks during the construction of the device, the researcher managed to overcome all those challenges such as material gathering, tools require for testing and construction, fixing the various components in their right positions to maintain the device’s safety and efficiency.
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1.8 Organization of the Study
Chapter one serves as the introduction to dissertation. In this chapter, the background to the study, statement of the problem, purpose and objectives, significance, limitations and delimitations and organization of the study were discussed. Chapter two presents a literature review on solar phone chargers. In this chapter, selected literatures which were relevant to the topic under discussion were reviewed. Chapter Three discusses the design methodology. It focuses on discussing all the methods used during the design and construction of the solar cell phone charger. Chapter Four presents the testing of the constructed solar cell phone charger. All the test results that resulted in accurate functionality were analysed. Finally; Chapter Five presents the conclusion and recommendations for further studies.
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CHAPTER TWO
RELEVANT LITERATURE REVIEW
2.0 Introduction
The main purpose of the dissertation is to design and construct a solar mobile charger for Kejetia traders. This chapter, which is the relevant literature review, looks at the introduction, Overview of Renewable Energy Resources, Historical Background of
Solar Cells, Solar Energy Resource in Ghana and Renewable Energy Act, Solar Energy and its sources. It further highlights on Theory of solar cells, Solar Photovoltaic
Technology and Principle, Efficiency of Solar Panels and lastly, the benefits of the Solar
Battery Charger.
2.1 Overview of Renewable Energy Resources
Making and accelerating access to clean energy has consecutively received global consideration (REN21, 2014). Renewable energy sources and technology encompasses solar, wind, wave, geothermal, tidal, hydro, and bio-energy energy, which in principle all receive their source from solar radiation (Hancock, 2015 & Boyle, 2012). Some of these are sometimes preferred for their greenness and relative easy application than others
(Boyle, 2012). Several authors have defined renewable energy (sources) in various ways, with all definitions pointing to one direction of a “regenerative” resource as the name implies (Chiras, 2013 & Maczulak, 2010). Twidell and Weir (2006,) define renewable energy as “energy obtained from natural and persistent flows of energy occurring in the immediate environment. Passionately, Quaschning, (2005) clearly defines the term as
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According to Quaschning, (2005) & Fouquet, (2009), as cited in Boateng (2016) narrate that at the launch of the 19th century, coal and crude oil were not significant as energy supplies for the world’s energy demand as renewable energy sources supplied an estimated 95 per cent of all global energy needs. Firewood and some skills for exploiting wind and hydropower were prominent in the provision of essential energy demand while fossil energy sources remained secondary in order of importance (Freris& Infield, 2008).
Nonetheless, the beginning of the 20th century observed a change of world’s energy supply from renewables to fossil fuels as it was found efficient, cheaper, and relevant to augment the accumulative popularity of industrialization and motorized road traffic, rendering most renewable energy resources less important in the global energy mix
(Quaschning, 2010 & Brown, 2008).
Again, Breiner, (2014) further fumes that up to date, fossil fuels have been exploited massively since its detection to fast-track global economic growth, urbanization, food production, population, and human mobility, which is labeled
“development” to the disadvantage of the natural environment and development inequality, which the same resource has caused in most developing countries. Break into shorter sentences] Current estimates have projected world’s oil reserves between 40 and
45 years (Chiras, 2013). Chiras further expressed that the forthcoming decline of fossil fuel reserves together with the environmental problems associated with the production and use has led to significant increase in the pursuit for non-depleting, green and equitable options, which distribution is independent of geographical location. This however, according to Chiras (2013) expressed in Boateng (2016) reflects renewable energy resources mainly solar energy, which is more favourable for rural energy demand.
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Freris and Infield (2008), posit that renewable energy can principally deliver the total energy services offered by conventional energy sources namely electricity, cooling, and heating with additional benefits and ability to provide energy to remote areas with no widespread energy transport systems as it remains naturally circulated resource.
Quaschning (2005) supports this observation by affirming that renewable energies can, theoretically, cover the global energy demand without any challenge.
In their research, Javadi et al. (2013) found that renewable energy sources are best suited for remote areas which are far from the grid though, grid connection is reliable.
This assumes that there is vast amount of energy accessible in renewables that can securely serve purposes with improved technology and favorable energy policies.
2.2 Historical Background of Solar Cells
The photovoltaic effect was first experimentally demonstrated by French physicist
A. E. Becquerel. In 1839, at age 19, experimenting in his father's laboratory, he built the world's first photovoltaic cell. Smee, (1849) in Perlin (2004). However, it was not until
1883 that the first solid state photovoltaic cell was built, by Charles Fritts, who coated the semi conductor selenium with an extremely thin layer of gold to form the junctions. The device was only around 1% efficient (Perlin, 2004). In 1888 Russian physicist Aleksandr
Stoletov according to Smee, (1849) cited in Gevorkian, (2007) built the first photoelectric cell based on the outer photoelectric effect discovered by Heinrich Hertz earlier in 1887.
The first practical photovoltaic cell was developed in 1954 at Bell Laboratories by Daryl
Chapin, Calvin Souther Fuller and Gerald Pearson (Gevorkian, 2007).They used a
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diffused silicon p-n junction that reached 6% efficiency, compared to the selenium cells that found it difficult to reach 0.5% (Perlin, 2004).
According to Perlin, (2004), solar cells were brought from obscurity by the suggestion to add them to the Vanguard I satellite, launched in 1958. In the original plans, the satellite would be powered only by battery, and last a short time while this ran down. By adding cells to the outside of the body, the mission time could be extended with no major changes to the spacecraft or its power systems. There was some skepticism at first, but in practice the cells proved to be a huge success, and solar cells were quickly designed into many new satellites, notably Bell's own Telstar(Gevorkian, 2007 &Perlin,
2004).
2.3 Solar Energy Resource in Ghana and the Renewable Energy Act
Ghana’s geographical location in the tropics positions the country to receive high solar radiation throughout the year in all the ten regions of the country (Boateng, 2016).
In Ghana solar energy assessment was undertaken in 2002 under the UNDP renewable energy project (Painuly & Fenhann, 2002; Gyamfi et al., 2015). This assessment was based on geostationary satellite Meteos at data and the average solar insolation (incident solar radiation) has been established as between 4.4 and 6.5 kWh/m2/day, a sunshine duration of around 1800-3000h per year and an average annual solar radiation of 16-29
MJ/m2 (Kemausuor, Obeng, &Duker, 2011; Schillings, Meyer &Trieb, 2004; Painuly &
Fenhann, 2002). These conditions are ideal for the exploitation of solar energy to improve the socio-economic and environmental conditions of isolated rural residents,
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considering the enormous solar radiation resources available in all the parts of the country.
In another development, Greenpeace (2010) scenario shows how over 80% of worldwide energy consumption would be supplied by a fusion of various renewable energy sources. Moreover, in 2008, Shell International Petroleum (2008) projected that by 2050; half of global energy production will come from renewable energy sources, in particular solar energy. It appears that the present discoveries are being acknowledged in practice, as there is rapid renewable energy technology improvement and acceleration of deployment in most developing countries, importantly isolated areas where energy demand is equally paramount.
Furthermore, consciousness has increased considerably during the last decades regarding the potential of renewable energy resources and technologies to meet rising energy demand in both developed and developing countries (REN21, 2014; Galarraga,
Gonzalez-Eguino & Markandya, 2011; IEA, 2007). Similarly, the implementation of renewable energy resources has been identified with the creation of jobs, acceleration of economic development, improvement in the quality of life of remote citizens in areas like healthcare, education, and reduction in carbon emissions (De Domingo, 2013; Belmonte,
Escalante & Franco, 2015).
2.4 Solar Energy and its Sources
The sun is a star made up of hydrogen and helium gas. It radiates huge amount of energy every second. Sunlight is composed of photons. Solar cell works on the principle of photovoltaic effect. These photons contain various amounts of energy corresponding to
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the different wavelengths of light (Ullah, 2013). When a photon is absorbed, the energy of the photon is transferred to an electron in an atom of the cell. The energy directly or indirectly harnessed from the infinite source of the natural sun is called the solar energy
(Akikur, Saidur, Ping, 2013). Solar energy is basically classified into the following continuum:
i. Passive and Active; passive is solar energy recovered without any mechanical
action, thus, simple utilization of daylight which may be through building designs,
whereas active is harnessing of solar energy to store or convert it into other forms,
like hot water systems, solar collectors among others (Boyle, 2012).
ii. Thermal and solar photovoltaic which exemplify the state of the art in active solar
electrification and iii. Concentrating and non-concentrating; thus the use of mirrors or lenses to focus
sunlight, which are all based on energy directly ascribed to the light of the sun or
generated heat from sunlight (Bradford, 2006; Chiras, 2013; Boyle, 2012).
Solar energy is classified as the earth largest source of renewable energy with active irradiance reaching the earth surface varying between 1 kW/m2 at high latitudes to
0.25kW/m2 at low latitudes (Timilsina, Kurdgelashvili, &Narbel, 2012; IEA, 2014). The solar power that reaches the earth surface annually is believed to be a total of about 885 million terawatthours (TWh), which is 6200 times the commercial primary energy consumed by humankind in 2008, and 4200 times the total forecast of human energy in
2030 (IEA, 2011).
Undoubtedly, the resource potential of solar energy greatly surpasses the total global energy demand, which in principle, rural and isolated energy needs can easily be
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met through rapid implementation of solar energy technologies to deliver improvement to rural economic, social, and environmental conditions (Kurokawa, Komoto, Van Den
Vleuten, &Faiman, 2007; Quaschning, 2005). Quaschning (2005) continued recounts that the annual solar radiation of Sahara and sub-Saharan Africa is about 2350 kWhm2/year and the total annual irradiation reception of around 8.7 million km2 far exceeds global annual primary energy demand, hence meeting local rural communities energy demand with renewables is comparably easy. Since the 1970s oil crisis, solar energy application has received increased consideration worldwide and a number of solar energy sources have been realized to provide electricity for rural and isolated communities in the form of stand-alone or hybrid systems, mostly in developing countries, which receives monthly average solar irradiation of 3±6kW/m2 (Akikur et al., 2013).
2.5 Solar Energy Process
Photovoltaic cells are made of special materials called semiconductors such as silicon. An atom of silicon has 14 electrons, arranged in three different shells. The outer shell has 4 electrons. Therefore a silicon atom will always look for ways to fill up its last shell, and to do this, it will share electrons with four nearby atoms. Now we use phosphorus (with 5 electrons in its outer shell). Therefore when it combines with silicon, one electron remains free. When energy is added to pure silicon it can cause a few electrons to break free of their bonds and leave their atoms. These are called free carriers, which move randomly around the crystalline lattice looking for holes to fall into and carrying an electrical current. As a result, a lot more free carriers in pure silicon will become N-type silicon. The other part of a solar cell is doped with the element boron
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(with 3 electrons in its outer shell) to become P-type silicon. When this two type of silicon interact, an electric field forms at the junction which prevents more electrons to move to P-side. When photon hits solar cell, its energy breaks apart electron-hole pairs.
Each photon with enough energy will normally free exactly one electron, resulting in a free hole as well. If this happens close enough to the electric field, this causes disruption of electrical neutrality, and if we provide an external current path, electrons will flow through the P side to unite with holes that the electric field sent there, doing work for us along the way. The electron flow provides the current, and the cell's electric field causes a voltage.
2.6 Theory of Solar Cells
The solar cell according to Perlin (2004) works in three steps:
1. Photons in sunlight hit the solar panel and are absorbed by semiconducting
materials, such as silicon.
2. Electrons (negatively charged) are knocked loose from their atoms, causing an
electric potential difference. Current starts flowing through the material to cancel
the potential and this electricity is captured. Due to the special composition of
solar cells, the electrons are only allowed to move in a single direction.
3. An array of solar cells converts solar energy into a usable amount of direct current
(DC) electricity (Perlin 2004).
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2.7 Solar Photovoltaic Technology and Principle
Solar photovoltaic (SPV) technology is focused on semiconductor materials designed to directly convert sunlight into electricity, thus; the electricity produced is delivered in the form of direct current (DC), which is suitable for several applications
(Boyle, 2012; Parida, Iniyan, &Goic, 2011). The IEA (2014) highlight two components of solar radiation:
1. direct radiation directly obtain from the sun, and
2. diffuse radiation reaching the earth indirectly once dispersed by the atmosphere,
which are both relevant for solar photovoltaic.
The development of solar photovoltaic technology as a superior method of harnessing energy from the sun dates back to the 1950s when high efficiency solar cells were developed by a group of scientists at Bell Labs in the United States (Haukkala, 2015
Bhattacharyya, 2014; Chiras, 2013). Since then, tremendous progress has been made in regard to increase efficiency, reduction in cost of production and price, and market expansion of solar energy systems over the decades (Boyle, 2012). The current development in the technology has coincided with continuous degeneration in the costs of owning and installing solar energy systems (Mustsaerts, & Sriwannawit, 2015). This trend has made it more attractive for developing countries to implement the technology as steps to poverty alleviation, improvement in the lives of rural people, and a definitive climate change mitigation strategy (Ulsrud et al. 2011). Between the year 2004 and 2013, nearly 139 GW photovoltaic capacity had been installed at the global level while the market prospect in sub-Saharan Africa has also proved promising with South Africa leading with (75 MW) installed solar photovoltaic capacity (REN21, 2014). Solar
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photovoltaic is remarkably known for its suitability for rural and remote power needs such as lighting, water pumping, telecommunications, and also applicable in several domestic, commercial, and industrial structures, which integrate grid-connected photovoltaic arrays to resource a significant part of their energy requirements (Boyle,
2012). Solar photovoltaic technology can be grouped into three major applications according to (ESMAP, 2007):
i. Stand-alone solar devices particularly built for end use purposes, such as water
pumping and home power, small radio set, and mobile phone charging;
ii. Small to medium solar power plants (mini-grids) designed to provide village level
electricity; and iii. Grid-connected solar-photovoltaic power system, which is usually connected to a
large conventional grid system to feed power into the public electricity grid
The different applications make solar photovoltaic systems the most economical, environmental, and socially equitable option for meeting rural energy demands and improving the lives of those who earn less than USD 1 to USD 2 per day while spending about USD 0.4 per day on inefficient energies such as wood fuels, kerosene, dry cell batteries, and general application of diesel generators (Akikur et al., 2013; IEA, 2011).
This study however, reflects the first category where stand-alone solar devices particularly built for end use purposes, specifically mobile phone charging.
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2.8 Efficiencies of Solar Panels
Depending on construction, photovoltaic panels can produce electricity from a range of frequencies of light, but usually cannot cover the entire solar range (specifically, ultraviolet, infrared and low or diffused light). Hence, much of the incident sunlight energy is wasted by solar panels, and they can give far higher efficiencies if illuminated with monochromatic light. Therefore, another design concept is to split the light into different wavelength ranges and direct the beams onto different cells tuned to those ranges. This has been projected to be capable of raising efficiency by 50% (Baldwin,
2011).
Currently, the best achieved sunlight conversion rate (solar panel efficiency) is around 21% in commercial products, typically lower than the efficiencies of their cells in isolation. The energy density of a solar panel is the efficiency described in terms of peak power output per unit of surface area, commonly expressed in units of watts per square foot (W/ft2) Baldwin, (2011) further expressed. The most efficient mass-produced solar panels have energy density values of greater than 13 W/ft2 (140 W/m2) (Baldwin, 2011).
2.9 Benefits of Solar Battery Chargers
The following are the benefits that solar battery chargers provide:
i. They do not require external electrical sources to recharge your batteries. This
means that solar battery chargers offer freedom of movement.
ii. You can find the sun anywhere on earth during the daytime depending on the
season. So Hence, if someone finds himself lost in the forest with a dead cell
phone battery, he needs only just the sun's rays to recharge his battery and running
again. 18
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iii. Solar cells generate no emissions, waste or by-products; those photons which are
not used simply pass through the silicon or bounce off it as they would any other
material. Usually, this electricity is produced by the transfer of energy from
photon to electron, which frees the electron and allows it to flow. Electricity is not
itself a form of energy, but an energy carrier. iv. While coal is a cheap and easy way to generate electricity, it is also a major
source of pollutants (Painuly & Fenhann, 2002).
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CHAPTER THREE
METHODOLOGY AND CONSTRUCTION
3.0 Introduction
This chapter discusses the methods used, construction of the solar panel, block diagram of the system, solar mobile charger circuit, circuit operation, functions of the components used, materials required, construction procedure and testing, specification of the charger, problem encountered and cost analysis of the constructed device.
3.1 Methodology
The researcher employed an experimental case study method. This method according to Maruish, (2000) is an in-depth study of a particular research problem rather than a statistical survey or comparative inquiry. The design has an advantage of extending experience or adding strength to what has already known been made available through previous research. As the study aims at constructing the most efficient, durable and cost effective solar mobile charger for charging mobile phones anytime and anywhere, its main focus is the selection of good quality components in relation to the variables which include load, charging current, and solar panel voltage to design the circuit for the mobile cell phone charger. Therefore, there is an attempt to manipulate these variables in order to achieve the desired objective.
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3.2 Construction of the Solar Panel
Four thin film photovoltaic cells were used for the construction of the solar panel charger. Each of the photovoltaic cell is rated at 5volts, 81mA and is connected in series and parallel to give an output of 10 volts and 162mA respectively. All the four photovoltaic cells were fixed on a square plastic cover and finally sealed with a water resistant sealant to prevent ingress of water into the charger.
Figure 3.1: Solar Panel Used Source: Field Study, 2017
3.3 Block Diagram of the System
A block diagram of the unit was constructed for easy comprehension. This diagram gives a pictorial overview and understanding of the work details as shown in
Figure 3.2;
Solar panel Filter Regulator Cell phone
circuit
Figure 3.2: Block Diagram of the System
Source: Field Study, 2017 21
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3.4 Solar Mobile Phone Charger Circuit
The circuit used for this project is shown below
10v Solar Panel Mobile Phone with 1300mA Battery Capacity Cable
Zener Diode Diode IC7805 + IN5402 +
100Ω
Input Resistor 10uf Output 10v 10uf to USB from solar 5v panel USB Port Red LED
indicator 6v Bank Battery
- _ Figure 3.3: Solar Cell Phone Charger Circuit Diagram - Source: Field Study, 2017 -
3.5 Circuit Operation
The constructed solar mobile charger is a device which can charge mobile phones using solar radiation. Its major component is a compact solar panel. This solar panel traps solar energy and produces an output voltage of 10v. But, since the light radiations falling on the solar panel can vary, the output voltage becomes unstable. For charging a mobile phone, stable voltage is required. So, to make the output voltage stable and regulated, the
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researcher used voltage regulator circuits which include IC7805 transistor and Zener
Diode along with the solar panel. The 1.5v RED LED indicator light was also incorporated to monitor the solar panel charging status. A resistor of 100ohms was connected in series with the LED to drop the voltage from 10v to 1.5v.This implies that the resistor always holds 8.5v for effective performance of the LED.
Input and output capacitors were also used to filter the unregulated and regulated voltage respectively. The Diode (IN5402) acted as polarity guard for the panel. The regulated 5v output voltage was used to charge both the battery bank and mobile charger.
Most of the mobile phones have USB cable connectivity. This USB connectivity utilizes
5v supply to recharge phone’s battery.
3.6 Function of the Components Used
Diodes
The output of the solar panel is fed through diode 1N5402 (D1), which acts as a polarity guard and protects the solar panel. The Diode was therefore used for protection against reverse polarity in case of wrong connection of the lead-acid battery. Also, the zener diode used acted as output voltage regulator.
IC7805
The IC7805 transistor was used to maintain the exact voltage (5v) which is followed by the power supply. This IC7805 is a three terminal device and mainly called input, output and ground. The input pin of the IC which is the positive terminal was connected to the unregulated voltage (10v) from the solar panel. Also the output pin of
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the IC terminal was connected to provide the regulated output voltage of 5v which is used to charge the phone and the battery bank. The ground pin remains neutral to both input and output.
Capacitor
The capacitor was used for filtering both input and output power of the device.
Toggle switch
The toggle switch was used to regulate ON and OFF of the unit
Battery
The rechargeable battery was used to store energy whenever the sunlight is unavailable especially during night hours.
USB Port
The USB port was used for connecting the mobile phone via USB cable for charging.
3.7 List of Components used for the Construction of the Solar Mobile Charger
Name of Component Diode
IC7805
Solar panel 10V, 2W IC 7805 (voltage regulator) 100uF. 5V capacitor
Recharggeable batteries(1.2×4)
USB female connector PCB Water sealant
Solder
Insulator tape Wires 24
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3.8 Construction Procedure and Testing
1. Wires were connected to the back side of the solar panel (Red colour to the
positive terminal and the white to the negative terminals) as in Figure 3.4.
2. The major components; IC7805, 100uF, 10uF, and diodes were fixed onto the
PCB
3. The PCB was tested by connecting voltage between 8 V and 10V to the input of a
voltage regulator. (The output should be constant and it can be any value between
4.5 V and 5.25V. If that is the case, it indicates that the circuit is working
properly).
4. Then, the USB port was connected observing the negative and the positive
connectors as indicated in Figure 3.5 and its output was eventually measured for
efficiency and proper functioning.
5. The positive and negative output wires of the USB were soldered to the PCB.
6. The solar panel was connected to the input of the regulator circuit (the positive of
the solar panel to the positive input and the negative of the solar panel to the
negative input).
7. Output voltage was measured in the open sun light to re check the required
voltage in direct sunshine. It recorded 4.56V indicating its efficiency.
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Fixing of the major components
Figure 3.4: Interior connections to the solar panel (back view of the panel)
Source: Field Study, 2017
Figure 3.5: Connections of some components on Printed Circuit Board (PCB)
Source: Field Study, 2017
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Figure 3.6: Interior components of the unit in fixed positions
Source: Field Study, 2017
After connecting all the components in their various sections i.e the solar panel, battery bank, and the printed circuit board components including switches and the LED indcator were finally fixed together in the plastic casing as shown above in Figure 3.7.
Also, a light metal sheet was used to lock both the solar panel and the plastic casing.See
Apendix C.
3.9 Testing of System Operation
At this stage the constructed charger was tested for its required efficient performance. Initially, the solar panel was mounted and the cable from the panel was also connected to the system, while the USB cable was also connected to the cell phone and then switched ON with the toggle switch. The system was set for operation, at this point; the cell phone started charging until it was fully charged. The indicator light was also connected whose function was mainly to indicate the presence of voltage in the system. 27
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3.10 Problem Encountered
The major difficulty or drawbacks encountered was during its installation where most of the external components did not mechanically respond as expected though this was later resolved.
3.11 Cost Analysis
The expenditure made in purchasing all the components / materials and quantity used in building this unit is tabulated as shown in Table 3.1;
Table 3.1: Cost Analysis of the Unit Constructed
Components Quantity Amount Gh¢ Total Gh¢ PV panel 4pcs cells 5.00 20.00 Capacitor 2 1.00 2.00 Rechargeable Batteries 4 15 60 Printed Circuit Board (PCB) 1 5 5 USB Port 1 5 5 Cables for fixing 1 metre 2 2 Transistor 2 1.00 2.00 LED lamp 2 1.00 2.00 Diodes 1 1.00 1.00 Switch 1 1.00 1.00 Total Gh¢100.00 Source: Field Study, 2017
Comparing cost of constructing the solar mobile charger which is ghc100 and cost of the conventional charger, which is 10ghc.It is analysed that, the solar mobile charger is ten times higher in terms of cost than the conventional charger. 28
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CHAPTER FOUR
RESULTS AND ANALYSIS
4.0 Introduction
This chapter which is the results and analysis of the dissertation presents the introduction, discussion of the results of the experiments, charging current and voltage of the solar mobile charger constructed, and charging duration for the solar mobile charger with a battery bank to fully charge a mobile phone (SumSang Android) with 1300mAh
Battery capacity. Also, the charging current and voltage of the battery bank alone in the solar mobile, charging time of SumSang Android mobile phone using the battery bank and charging time of a conventional (AC) charger were presented.
4.1 Discussion of the Results of the Experiments
This chapter discusses the results obtained from the experiment conducted to determine the functionality of the unit constructed.
4.2 Charging Current and Voltage of the Solar Mobile Charger Constructed
The researcher made an attempt to find out the charging current and voltage of the
Solar Mobile Charger constructed via experiment using an ammeter and voltmeter. From experiment 1A, it was indicated that the charging current of 0.05A was obtained for initial charge and 0A was eventually observed for the final charge. Also, from experiment
1B, it was further observed that, the charging voltage was 4volt D.C. The diagrams in Fig
4.1 and Fig 4.2 below display the experiments.
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Experiment 1
Experiment 1A shows the Connection of D.C Ammeter in series to both solar mobile charger and mobile phone in measuring the current
Samsung Android Mobile DC Ammeter Solar Mobile Charger with Phone Battery Bank
Figure 4.1: Connection of the D.C Ammeter (0 – 1A) to the Solar Mobile Charger Source: Field Study, 2017
Experiment 1B shows the connection of D.C Voltmeter (0 – 10v) in parallel to both solar mobile charger and mobile phone to measure the charging voltage.
Samsung Android Solar Mobile Charger
Mobile Phone Voltmeter with Battery Bank
Figure 4.2: Connection of the D.C Voltmeter (0 – 10v) to the Solar Mobile Charger Source: Field Study, 2017
Experiment 2
4.3 Charging Duration for the Solar Mobile Charger with Battery Bank to Fully
Charge a Mobile Phone (Samsung Android) with 1300mAh Battery Capacity
The researcher further made an attempt to find out the specific amount of time the device used to charge a Samsung Android phone. From both Fig 4.4 and Table 4.1, it was observed that, the device constructed (with its in built battery bank) took 360 minutes
(6hrs) to fully charge the Samsung Android mobile phone with 1300mAh battery capacity as shown in Figure 4.3 and Table 4.1 below. 30
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Table 4.1: Charging Time for Samsung Android Mobile Phone Using Solar Mobile
Charger with a Battery Bank
Charging Time (Min.) Percentage of Charge Charged Battery Capacity of Cell phone 0 - 60MINS 17% 221mAh 60 -120MINS 34% 442mAh 120-180MINS 50% 650mAh 180-240MINS 67% 871mAh 240-300MINS 84% 1092mAh 300-360MINS 100% 1300mAh Source: Field study; 2017
Figure 4.3: Charging Time for Samsung Android Mobile Phone Using Solar Mobile
Charger with a Battery Bank
Source: Field Study, 2017
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Procedure
i. Connect the mobile phone to the Solar Mobile Charger with battery bank
ii. Set a time to start charging it and take note of the time it takes to be fully charged.
Charger Cables Samsung Android Mobile Solar Mobile Charger with Battery Bank1300mAh
Battery Capacity
Figure 4.4: Connection of Samsung Android mobile phone to the solar mobile
charger
Source: Field Study, 2017
Experiment 3
4.4 Charging Current and Voltage of the Battery Bank Alone in the of Solar
Mobile Charger
Additionally, both the current and voltage of the device’s battery bank were tested. It was observed that the current was 0.04A while its voltage was 4.8volts as indicated in the procedures shown in figures 4.5 and4.6 below.
Procedure 3A(D.C Current)
Connect D.C Ammeter (0-1A) in series with both solar mobile phone charger and
Samsung android mobile phone.
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Switch on the toggle switch on the solar mobile charger to connect battery bank to
the Samsung android mobile phone and take note of the charging current. See
figure 4.5 below.
Note: The toggle switch can be located on the solar mobile charger
Samsung Android Mobile Ammeter Solar Mobile Charger with
Phone Battery Bank
Figure 4.5: Measuring the charging current of the battery bank of the solar mobile
Charger using a D.C Ammeter
Source: Field Study, 2017
Procedure 3B (D.C Voltage)
Connect D.C Voltmeter (0-10v) in parallel to both solar mobile charger and
Samsung mobile phone.
Switch on the toggle switch on the solar mobile charger to connect battery bank to
the Samsung mobile phone and take note of the charging voltage.
Samsung Android Solar Mobile
Mobile Phone Voltmeter Charger with
Battery Bank
Figure 4.6: Measuring charging current of the battery bank of the solar mobile
Charger using D.C Voltmeter.
Source: Field Study, 2017
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Experiment 4
4.5 Charging Time of Samsung Android Mobile Phone Using the Battery Bank
Alone in the Solar Mobile Charger
Similarly, the time it takes for the battery bank in the device to fully charge the
Samsung Android mobile phone was checked. It was observed that, the battery bank took
450 minutes (7.5hrs) to fully charge the phone with the same battery capacity (1300mAh) as shown in Figure 4.7 and Table 4.2 below. This was done to check the differences in charging time between the battery bank and the solar panel charger. This means that the battery bank of the device sustains its power partially from the solar panel. Also, there was a charging time difference of 90 minutes (1.5hr) between the battery bank and the solar panel.
Table 4.2: Charging Time of Samsung Android Mobile Phone Using the Battery
Bank Alone in the Solar Mobile Charger
Charging Time (Min.) Percentage of Charge Charged Battery Capacity of Cell phone 0-60MINS 13% 173mAh 60-120MINS 27% 346mAh 120-180MINS 40% 519mAh 180-240MINS 53% 693mAh 240-300MINS 67% 867mAh 300-360MINS 80% 1040mAh 360-450 MINS 100% 1300mAh Source: Field Study: 2017
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Figure 4.7: Charging Time of Samsung Android Mobile Phone Using the Battery
Bank Alone in the Solar Mobile Charger
Source: Field Study, 2017
Experiment 5
Charging Current and Voltage
The researcher further used the conventional (AC) charger to charge the Samsung
Android phone to determine the charging current and voltage for comparative purposes.
From procedure 5A, the charging current of 0.5A was observed for initial charge and
0.0A for final charge. The charging voltage was also observed as 5volts from procedure
5B.
Comparatively, the charging current of the solar mobile charger was 0.05A with voltage 5volts as observed in experiment 1A and 1B respectively. It implies that the conventional (AC) charger has a charging current which is 10 times (10*) higher than the
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solar mobile phone charger while their charging voltage remained constant. See Fig4.8 and Figure 4.8 below.
Procedure 5A
Connect D.C Ammeter (0 – 1A) in series with both conventional (AC) mobile phone charger and Samsung mobile phone.
Samsung Android Mobile Ammeter Conventional (AC) Mobile
Phone Phone Charger
Figure 4.8: Connection of the D.C Ammeter (0 -1A) to measure the conventional
charging current
Source: Field Study, 2017
Procedure 5B
Connection of D.C voltmeter (0 – 10v) in parallel to both the conventional mobile phone charger and Samsung mobile phone
Samsung Android Voltmeter Conventional (AC)
Mobile Phone Mobile Phone
Charger Figure 4.9: Connection of the D.C voltmeter (0 – 10v) to measure the conventional
charging voltage
Source: Field Study, 2017 36
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Experiment 6
4.6 Charging Time of a Conventional (AC) Charger
Similarly, the charging time was further observed using conventional (AC) charger. From Fig 4.10 and Table 4.3, the Samsung Android mobile phone with
1300mAh battery capacity took 60minutes to charge the battery fully. It is clear from both table and the graph that, there was a direct correlation between the time and the charging percentage. Comparatively, the charging time of a conventional (AC) charger was 60 minutes while a solar mobile charger took 360 minutes which represents a difference of 300 minutes (5hr). This is an indicative of the fact that the solar mobile charger takes a longer time to be fully charged compared to the conventional (AC) charger. This was due to the small current (milliampere) generated by the solar panel
(cells).
Table 4.3: Charging Time of Samsung Android Mobile Phone Using Conventional
Charger
Charging Time(mins) Percentage of Charger Charged Battery Capacity of Phone 0-10 17% 221mAh 10-20 34% 442mAh 20-30 50% 650mAh 30-40 67% 871mAh 40-50 84% 1092mAh 50-60 100% 1300mAh Source: Field Study; 2017
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Figure 4.10: Charging Time of Samsung Android Mobile Phone Using Conventional
Charger
Source: Field Study, 2017
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CHAPTER FIVE
SUMMARY OF FINDINGS, CONCLUSIONS AND
RECOMMENDATIONS
5.0 Introduction
The main purpose of the study was to design and construct a suitable cell phone solar charger which could be used to charge mobile phones everywhere at any time. This chapter presents the summary of the project and finally, draws conclusions, recommendations and suggestions for further research.
5.1 Summary of the Findings
The following findings were made;
i. The charging current for the solar mobile charger was0.05A as against 0.5A for
the conventional (AC) charger.
ii. The maximum charging voltage for both solar and conventional mobile chargers
was constant and fixed at 5volts. This was due to the voltage regulation
components (IC7805) in the device. iii. The charging time for the solar mobile charger was 360 minutes; thus 6hrs
compared to the conventional (AC) charger which was 60 minutes (1hr). iv. The charging current and the charging voltage of the solar charger depend on
daily radiation capacity. The higher the daily sun radiation capacity, the more the
charging current and charging voltage.
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v. The solar mobile phone charger cannot generate electricity at night when there is
no sun. Therefore, the battery bank was needed to help it work consistently at all
times.
vi. The solar mobile phone charger takes a longer period to charge phone batteries to
their full capacity. This is as a result of the solar cell current generation capacity
being very small as micro or milliamps.
vii. The charging current of the conventional (AC) charger was 10 times greater than
the solar mobile charger. Hence, the conventional (AC) charger is faster than the
solar mobile charger viii. The battery bank’s full voltage was 4.8v yet it took a longer period of 420 minutes
(7hr) to charge.
ix. For the construction of the device there were some drawbacks, particularly in the
fixing of the external mechanical components it was resolved.
5.2 Conclusion
The findings of the study indicate that the solar charger takes a longer time to
fully charge a phone’s battery, which constitutes a disadvantage. Generally, the product
after construction seems portable, efficient, durable, robust, and above all
environmentally friendly. The solar powered mobile charger would not be able to
generate electricity on a cloudy day or at night, hence, the introduction of a battery bank
in the device for storage of power during the absence of sunlight. As a result, the more
convenient approach was to use batteries to store the solar energy which may not be
immediately used.
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5.3 Recommendations
It is recommended that;
i. Qualified personnel should be engaged in its maintenance.
ii. Proper clearing should be carried out. This relates to the solar panels that have
been surrounded by trees and weeds to reduce the effect of sunshine. iii. It should be used in homes, offices and market places where the demand for a cell
phone charging is high.
5.4 Suggestions for Further Research
For future research, the charging can be improved by adding an amplified circuit to the design. Also, the scope of the research could be extended to obtain more results which cover a broader scope.
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APPENDIX A
INSTRUCTION TO THE USER
1 Introduction
The solar mobile charger is a high power, high capacity, solar powered emergency charger. It stores energy from the sun in its internal 1300mAh battery bank capacity enabling you to charge your mobile phone whilst you are out and about. It can be used anywhere to recharge mobile phones with battery capacity not more than
1300mAh. Robust, lightweight and compact, it easily can be carried whilst travelling and is ideal for outdoor use by people like Kejetia traders who sell under the sun.
2. Main features:
Emergency solar battery bank charger
For mobile phones and personal digital devices.
Robust and compact design
Charged by solar energy
Monocrystal silicon photovoltaic panel
Red LED indicator
Built- in LED torch for emergency light
Battery bank capacity of 1300mAh/4.8v
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3 Parts and Functions
Solar Panel
Red LED indicator
Toogle Switch
LED lamp
How to charge the battery bank
Switch on the device using toggle switch and place it in direct sunlight. The sunlight will be transformed and automatically to recharge the built - in battery bank.
Whilst charging, red LED indicator on the front side will light, this LED increases and decreases in brightness according to the power being captured by the solar panel. In order to improve on the battery bank efficiency, it is suggested to complete two cycles of charge and discharge sequence of operations before using the device.
How to charge mobile phone
Switch on the device using toggle switch and place it in direct sunlight. Connect the mobile phone to the device using USB cable. The sunlight is transformed to charging current which is used to charge the mobile phone. Whilst charging, red LED indicator on 50
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the front side will light, this LED increases and decreases in brightness according to the power being captured by the solar panel.
4 Specifications of Charger
The following are the specifications of the unit (solar cell charger) to be constructed
Solar panel output voltage- 10V DC/162mA
Battery Bank Capacity (Rechargeable)-1300mAh
Battery Bank Voltage- 4.8v D.C (1.2v x 4)
Charging Current (On – Load)-0.05 (50mA)
Charging Voltage (On – Load)-4.56 volt DC
Output Voltage of solar charger5.25 volts D.C
No- Load battery charging voltage of the solar mobile charger5volt DC
Charging time by solar energy-6hrs
5. Safety instructions
Never apply direct pressure or scratch the solar panel with sharp object
Use only compatible USB cable for connecting the device. Failure to do so can
cause personal injury, damage the device and will invalidate the warranty.
Keep the product away from water and do not store in a damp environment.
For further information contact charlesaddo615@gmail 0267339801/0277185310.
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APPENDIX B
MAJOR COMPONENTS USED
Name of Component Purpose Image
Acted as a polarity DIODE guard and protect the solar panel
Stores electrostatic CAPACITOR stress in the dielectric
SWITCH Used to regulates ON and OFF of the unit
BATTERY Stores energy for future use
USB PORT Used for USB cable connections
CABLES Used to connect components (solar panel to the regulator
circuit)
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Soldering Iron Used to permanently fixed the components
PCB Houses the electronic components of the
device and the USB
port
Battery Bank Holder Holds rechargeable batteries
Source: Field Study, 2017
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APPENDIX C
INTERNAL VIEW OF THE UNIT
Interior components of the unit in fixed positions Source: Field Study, 2017
Interior connections to the solar panel (back view of the panel) Source: Field Study, 2017 54
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Connections of some components on Printed Circuit Board (PCB)
Source: Field Study, 2017
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APPENDIX D
THE UNIT IN USE
Source: Field Study, 2017
The Device in use Source: Field Study, 2017
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