INTRODUCTION

1.1 BACKGROUND OF THE STUDY

A power bank is a portable battery charger, or recharger,[1][2]  which is used to put energy into a secondary cell or rechargeable battery of a cell phone by forcing an electric current through it. 

This device supplies power from its built-in battery through a charging port. Power banks are popular for charging devices when little adjustment is made on it. They can also be used as a power supply for various powered devices such as lights and small fans. They usually recharge with a  power supply. The power bank includes a control circuit that both regulates charging of the battery and converts the battery voltage for the device. Some chargers for cells like 18650s and 26650 can also serve as a power bank. Although it is generally more cumbersome to carry such a charger with cells rather than a conventional power bank, this type of setup has the advantage of being able to charge cells for other uses. It also has the advantage that, when the cells are dead, they can be swapped for fresh cells for immediate use rather than having to be recharged first.

1.2 PROBLEM STATEMENT

Sometimes there is nothing worse than losing all the charges on your cell phone especially when you are in the middle of something very important. Usually this happens at the most inconvenient time probably when you are using your cell phone to surf the web, in the middle of a browsing or when you are desperate to send an important email or text message. Nonetheless, in this dispensation of global village, there is never a good time! If you are always on the move and you never know whether there is power supply in the place you are moving to, the very last thing you would imagine is to have your cell phone low or even empty on battery. For those who depend largely on their mobile devices, not having enough power for the battery can be a major catastrophe. How else will people reach you or how will you call/text people for business or personal reasons when your cell phone is basically useless as it has gone off on you? All these are problem to our present time, to bring this problem to an end, power bank was introduced which is a portable device that can supply power using stored energy in its built-in batteries [1,2]. 

1.3 AIM AND OBJECTIVES OF THE PROJECT

The main aim of the project is to build a solar power bank. The objectives of the work are:

i. To build the prototype of the device that is solar dependable that can be used to recharge portable devices such as cellphone when and where there is no power supply to recharge the device.

ii. To provide efficiency, steadiness in the use of power appliances, by ensuring continuous availability of power supply in the cause of main outage during an execution of an important or urgent assignment. 

iii. To reduce carbon discharges and subsequently reduce global warming 

1.4 SIGNIFICANCE OF THE PROJECT

Solar Power bank serve as an ‘extra battery’ or external charger for your phone or other electronic devices. Solar Power bank helps to ensure longer hours of texting, phone calls, or web browsing using your mobile phone.

1.5 SCOPE OF THE PROJECT

Cell-phone batteries often die at very inconvenient times, with no ac power outlet nearby. This device uses  standard AA batteries, which can be bought almost anywhere, to recharge cell phones and other portable devices like music players, e-book readers, and cameras. A connector is added to complete the design. The type of connector will depend on the device to be charged. Cell phones require the Micro-USB “type B” receptacle connector.

The circuit chargers that typically come with cell phones and other portable devices charge the battery for a brief period of time. Then, they stop, check the voltage, and verify the temperature against an internal table before deciding to stop or continue the charging process. The charging regulation required by the battery is performed within the device getting charged, and this design takes advantage of that circuit.

1.6 LIMITATION OF THE PROJECT

• It can only be recharged with solar energy through solar panel

• The duration of the charged when in used depend on the number of cell used.

• Using solar energy for this device means that charging the power bank during cloudy or raining time becomes a problem.

1.7 METHODOLOGY

To achieve the aim and objectives of this work, the following are the steps involved:

i. Study of the previous work on the project so as to improve it efficiency.

ii. Draw a block diagram.

iii. Test for continuity of components and devices, 

iv. Design of the system was carried out.

v. Studying of various component used in circuit.

vi. Construct of the system circuit.

vii. Finally, the whole device was cased and final test was carried out.

1.8 PROJECT WORK ORGANISATION

The various stages involved in the development of this project have been properly put into five chapters to enhance comprehensive and concise reading. In this project thesis, the project is organized sequentially as follows:

Chapter one of this work is on the introduction to the study. In this chapter, the background, significance, objective, limitation and scope of the study were discussed.

Chapter two is on literature review of this study. In this chapter, all the literature pertaining to this work was reviewed.

Chapter three is on design methodology. In this chapter all the method involved during the design and construction were discussed.

Chapter four is on testing analysis. All testing that result accurate functionality was analyzed.

Chapter five is on conclusion, recommendation and references.