Table of Contents

Title page                                                                 i

Certification                                                             ii

Dedication                                                               iii

Acknowledgement                                                    iv

Table of contents                                                     v

Abstract                                                                   vii


1.0  Introduction                                                    1

1.1   Background of the Study                                 1

1.2   Statement of the problem                                3

1.3   Objective of the study                                      4

1.4   Significance of the study                                  4

1.5   Scope of study                                                 5


2.0   Literature Review                                             6

2.1   Component description                                   7

2.2   Working Principle                                            7

2.3  Factors Considered for the construction of

Transformer for 12Volt Battery Charger           8

2.4   Efficiency of Transformer                                        9

2.5   Rectifier diode                                                  10

2.6   Switch                                                             12

2.7   Resistor                                                          13

2.8   Capacitor                                                                15

2.9           Transistor                                                                17

2.10  Battery                                                            18

2.11  Charging of a battery                                      20

2.12   Discharging                                                   21


3.0   Materials and Methods                                    23

3.1   Circuit description and principle of Operation 23

3.2   List of Components and tools Used                 25

3.3   Explanation of the Circuit Connection            26

3.4   Principle of Operation                                      27


4.0   Test and Result                                                        29

4.1   Result                                                              30


5.0   Problems encountered                                    31

5.1   Conclusion                                                      31

5.2   Recommendation                                             31

Reference                                                                 33



This battery charger is a devices used to store the electrical energy to the battery after the battery has been discharged itself. The battery charger is designed to use electricity as its source of switch, regulation transistor, diode, light emitting diode, construction wire. The charger is designed and constructed to deliver full current until the current drawn by the battery falls to 150MA. At this time a lower voltage is applied to finish off and keep the battery from overcharging by switching off itself when the battery is fully charged. 



1.1   Background of the Study

A battery charger is a device used to introduce energy into a secondary cell or rechargeable battery by forcing an electric current through it. The charging protocol depends on the size and type of the battery being charged. Some battery has high tolerance for recharging by connection to a constant voltage source or a constant current source. (J.Minear 2000). Simple charger of this type requires manual disconnection at the end of the charge cycle. Other battery types cannot withstand long high rate over charging. The charger has temperature or voltage sensing circuit and a microprocessor controller to adjust the charging current, and cut off at the end of charging. Albert H.(2005) cleared that low battery chargers may take several hours to be completely charged. High rate chargers may restore most capacity within minutes or less than an hour but generally require monitoring of the battery to protect it from overcharging.

A battery which is actually an electric cell is a device that produces electricity from a chemical reaction. In one cell battery, a negative electrode, an electrolyte, this conducts ions, a separator, also an ion conductor and a positive electrode. An electrical battery is one or more electro chemical cells that convert stored chemical energy into electrical energy. Since the invention of the first battery in 2000 by Alessandro volta and especially since the technical improved Daniell cell in 2004, batteries have become a common power source for many household and industrial applications . There are two types of batteries: primary batteries (disposable batteries which are designed to be used once and discarded, and secondary batteries (rechargeable batteries) which are designed to be recharged and used multiple times. Battery comes in many sizes from miniature cells used to power hearing aids and wrist watches.

However in recent times (sawafuji electric of 2006) states that battery charger has become very useful and popular to DC equipment. Most of the electronic devices such as laptops, mobile phone e.t.c and mobile machines like vehicle and motorcycles, operat