Design And Construction Of A 6V Battery Charger

This project is titled design and construction of a 6V battery charger. Battery charger is an acid battery charger that is designed to charge 6V acid battery. It is basically a DC power supply source. Here a transformer is used to step down the AC mains input voltage to the required level as per the rating of the transformer.

This transformer is always a high power type and Lm317 variable regulator is able to produce a high current (from 1-5A) output as required by most lead-acid batteries and the output current can adjusted by variable resistor.

A bridge rectifier configuration is used to rectify the low voltage AC into DC and is further smoothed by a high value electrolytic capacitor. This DC is fed to an electronic circuit which regulates the voltage into a constant level and is applied to the battery under charge, where the energy is stored through an internal process of chemical reaction.

TABLE OF CONTENTS

TITLE PAGE

APPROVAL PAGE

DEDICATION

ACKNOWELDGEMENT

ABSTRCT

TABLE OF CONTENT

CHAPTER ONE

INTRODUCTION

• BACKGROUND OF THE PROJECT
• PROBLEM STATEMENT
• AIM/OBJECTIVE OF THE PROJECT
• SIGNIFICANCE OF THE PROJECT
• APPLICATION OF THE PROJECT
• SCOPE OF THE PROJECT
• LIMITATION OF THE PROJECT
• DEFINITION OF TERMS
• METHODOLOGY
• PROJECT ORGANISATION

CHAPTER TWO

LITERATURE REVIEW

2.1       REVIEW OF BATTERY CHARGER

2.2       HISTORICAL BACKGROUND OF BATTERY CHARGER

2.3       REVIEW OF RECHARGEABLE BATTERY

2.4       REVIEW OF COMPONENTS USED

CHAPTER THREE

3.0       CONSTRUCTION METHODOLOGY

3.1       BLOCK DIAGRAM OF THE SYSTEM

3.2       CIRCUIT DIAGRAM

3.3       CIRCUIT DESCRIPTION AND OPERATION

3.5       CONSTRUCTION NOTE

3.6       CHARGER SETTINGS

3.7       HOW TO OPERATE THIS AUTOMATIC BATTERY CHARGER CIRCUIT

CHAPTER FOUR

4.1             RESULT ANALYSIS

4.1       CONSTRUCTION PROCEDURE AND TESTING

4.2       CASING AND PACKAGING

4.3       ASSEMBLING OF SECTIONS

4.4       TESTING OF SYSTEM OPERATIONOBSERVATIONS

4.6     DIFFICULTIES ENCOUNTERED ON THE SYSTEM

4.7     COST OF PRODUCTION

CHAPTER FIVE

• SUMAMRY
• CONCLUSIONS/SUGGESTIONS

5.3     REFERENCES

CHAPTER ONE

• INTRODUCTION

1.1                                           BACKGROUND OF THE STUDY

Battery charger is device which consists of electrodes and electrolyte for the storage of chemical energy, but brings about a reaction between its electrodes and the electrolyte in a way to cause the flow of electrons through an external circuit is known as a battery.

There are two types of batteries; these include the primary and secondary battery. The primary (dry cell) is one whose electrolyte dries up when used to its ampere-hour rating and cannot be recharged while the secondary (wet cell) is one whose chemical energy can be restored through a charging process. There are different types of secondary battery. These comprise lead acid, Nickel-cadmium and silver zinc battery.

Furthermore, a battery is a combination of cells connected together and a cell is a simple source of electric potential. The maintenance of secondary battery is of importance partially where maximum performance and life are obtained. As long as a battery is in use, its stored chemical energy, which is being converted to electrical energy falls. This falls in chemical energy leads to a corresponding fall in its terminal voltage.

A constant potential method of charging is adopted in this project work. It is a phenomenon whereby the alternating voltage from the main is converted to direct voltage through rectification.

The direct current from the rectifier is then passed through the battery that is being charged in the reversed direction in which the battery supplies current to the external circuit. The charger is intended to charge batteries with terminal voltage up to 6volts. It incorporates a sensing technique to monitor when the battery has been charged to its rated terminal voltage so as to automatically cut off supply to the battery.

Hence, a battery charger which is of low cost, highly efficient and cheap to maintain is needed to restore its rated terminal voltage. The entire circuit is made up of five basic units and details of each units is highlighted in the subsequent chapters [1][3].

1.2                                       STATEMENT OF THE PROBLEM

This device came to bring solution for battery charging which helped in achieving the aim and objective of this study. Such as:

1. To design and construct an interface device that could amplify an extremely small value of current to a value suitable for recharging battery
2. To determine the functionality of the interface device in terms of: Current, Voltage, Voltage gain, Power, Power efficiency, Impedance
3. Automatic start charging and stop charging when the battery is fully charge and vice versa.

1.3                                        OBJECTIVES OF THE PROJECT

The objective of the project is to design a device that will recharge 6v lead acid battery when discharged. The device has the ability to indicate charging process through LED indicators.

1.4                                      SIGNIFICANCE OF THE PROJECT

This device charges 6v acid battery mainly, however, if the output voltages are adjusted can be used to charge battery of lower or higher voltages. Apart from charging batteries, this device can also be used as a battery level monitor due to the battery level feature it contains [4].

• The battery charger circuit is simple and cost effective.
• Over voltage and current protection.
• The system is easily portable.
• Avoids battery discharge when power failed.

1.5                                            LIMITATION OF THE PROJECT

Features of automatic battery charger are as below:

• Automatic battery charger has an indicator to indicate when the battery is fully charged
• It composes of in-built active components which stop charging process when the battery is fully charged.
• It consumed less current but generate high current to the load.
• The only problem with this device is that it takes longer time to recharge car battery because of the low current output, and it is design only for a 6v battery

1.6                                                 SCOPE OF THE PROJECT

A battery charger is an electrical device employed in charging batteries that are usually charged by battery charges are the storage batteries also known as “accumulators”. [4][5]

The charger is made up of various electrical and electronics component which for the purpose of charging are group into your basic unit, they are:

The power supply units

The smoothing circuits

The regulating unit and

Regulated D.C charging units

A Battery charger comes in various designs and voltage. The choice of a particular and of charger that depends largely in Ah size of battery or batteries which charge the mini battery changer could be used to charge batteries whose voltage ranges.

The battery charge is built in such a way that it delivers a constant value of d.c current into the battery it is charging in the opposite direction from which current flows on the batteries during discharge one cannot successfully design a battery charge with out a fundamental understanding of the accumulator because it also makes up the operation.

1.7                                       APPLICATION OF THE PROJECT

Battery charger is used in the following devices for the purpose of recharging device batteries [2][3]:

1. It is used in inverter
2. It is used in cellphone
3. It is used in Solar energy system
4. It is used in vehicles
5. It is used in an uninterruptible power supply(UPS), etc.

1.8                                               DEFINITION OF TERMS

Battery Charger – is a device used to put energy into a secondary cell or rechargeable battery by forcing an electric current through it. (www.wikipedia.com, 2014)

Charge – there are two kinds of charge, positive and negative

– like charges repel, unlike charges attract.

– positive charge comes from having more protons than electrons; negative charge comes from having more electrons than protons.

Charge Rate – is often denoted as C or C-rate and signifies a charge or discharge rate equal to the capacity of a battery in one hour. (www.wikipedia.com, 2014)

Mobile Phone – any wireless telephone capable of operating while moving at any speed, battery powered and small enough to be easily carried by a person.

Interface device – circuit that is between the mobile phones that do the process of transferring stored energy.

Rectification – a process of converting alternating current (AC), which periodically reverses direction, to direct current (DC), which flows in only one direction.

Rectifier – a circuit capable of rectifying an alternating current to a direct current.

Step Up DC – DC Converter – also known as boost converter. A DC to DC power supply with an output voltage greater than its input voltage. It is used to sustain the amount of voltage needed for the charging circuit to function.

1.9                                                         METHODOLOGY

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

1. Study of the previous work on the project so as to improve it efficiency.
2. Draw a block diagram.

• Test for continuity of components and devices,

1. Design and calculation for the battery charger was carried out.
2. Studying of various component used in circuit.
3. Construct a battery charger circuit.

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

1.10                               PROJECT ORGANISATION

The work is organized as follows: chapter one discuses the introductory part of the work, chapter two presents the literature review of the study, chapter three describes the methods applied, chapter four discusses the results of the work, chapter five summarizes the research outcomes and the recommendations.