Design And Construction Of A 6V And 12 Volts Authomatic Battery Charger

ABSTRACT

This project is titled design and construction of a 6 and 12V automatic battery charger. A 6 and 12volts Automatic battery charger is a dual acid battery charger that is designed to charge 6v and as well 12v battery.

This automatic charger 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. And the selection of voltage is done using single pole double throw switch whenever there is need for that. That is, whenever there is a 6v battery to be charged, the switch would be sued the select the required voltage from the charger and vice-versa.

This transformer is always a high power type and is able to produce a high current output as required by most lead-acid batteries.

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.

In automatic battery chargers a voltage sensor circuit is incorporated to sense the voltage of the battery under charge. The charger is automatically switched OFF when the battery voltage reaches the required optimum level.

TABLE OF CONTENTS

 TITLE PAGE

APPROVAL PAGE

DEDICATION

ACKNOWLEDGEMENT

ABSTRACT

TABLE OF CONTENT

CHAPTER ONE

CHAPTER ONE

1.0                                       INTRODUCTION

Battery charger is an electronics device used in charging and recharging batteries when a battery is used up by the instrument connected to it. This electronics device has the ability to stop charging when the battery is fully charged and starts charging when the battery voltage drops below the set point

The 6 and 12-volt battery charger uses household current to put an electric charge into a discharged battery. The charger’s circuits convert 240-volt household alternating current (AC) to the 12-volt direct current (DC) that the battery needs.

This charger will charge any 6V and 12V lead acid battery including flooded, gel and AGM. It is fully automatic and will charge at a rate up to about 4A until the battery voltage reaches a preset point at which it will switch to a very low current float charge. If the battery voltage drops again the charger will begin charging until the voltage once again reaches the cut off point. In this way it can be left connected to a battery indefinitely to maintain full charge without causing damage. An LED indicates when the battery is fully charged.

A 6V and 12-volt battery charger is roughly the size of a car battery. It has a thick cable ending in two heavy-duty copper alligator clips, a black clip for the battery’s negative terminal and a red one for positive. The charger has an on-off switch and a meter to indicate charging power.

• OBJECTIVE OF THE STUDY

The main objective of this course is to design and construct a dual 6V and 12V automatic battery charger that can charge batteries of 6V and as well as 12V.

1.2     ADVANTAGES OF AUTOMATIC BATTERY CHARGER

The main advantages of this battery charger over other chargers is the ability of the charger to indicate battery charging levels and also the ability to stop charging when the battery is fully charged and resume charging when the battery level drops below  the set level.

   1.3                      SIGNIFICANCE OF THE COURSE

Features of automatic battery charger are as below:

• Automatic battery charger has an indicator to indicate when the battery is fully charged
• Built in Indications for showing Full, Empty Levels of any type of battery
• It has two manually operated switch that is used to ON and OFF the entire system, that is the first switch and the second switch that is used to select the charging voltage, either from 6V to 12V or from 12V to 6V..
• 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.

1.4     BATTERY CHARGE

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”.

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 from 6 – 12 volts.  The bigger battery changes are for batteries with voltage ranging from 12 – 48 volts.  These are the heavy duty batteries.

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.

Thus chapter two aimed at a brief study of the accumulator (battery).  Chapter three deals with the power supply units which series as the backbone of the battery charger and how the automatic cut off is achieved.

Chapter four fully analysis the operates of the battery charger and its casing which chapter five which happen to be the last chapter aimed at concluding and  summarizing what has been achieved at the end of the project.