Design And Construction Of 12v Battery Charger

ABSTRACT

This battery charger is a device 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.

CHAPTER ONE

INTRODUCTION

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.

The life span of a battery mostly used by automobile drivers can be maximized by avoiding over loading, overcharging, and inputting charge current higher than battery manufacture’s rated value (Bangaru, at al, 2013). It was observed over time that most commercial battery charging service centers in town (Enugu, Nigeria) that are patronized by automobile drivers uses the conventional battery charger type that is built without an automatic charging cut-off circuit to provide charging services to their customers. The unavailability of this automatic charging cut-off circuit causes the operator to constantly be on manual check to determine when the connected battery is charged (Baker, 2014).

Irrespective of the discharge level of the battery received from customers, the service center operator often connects the battery and allows it to charge over night without monitoring. This frequent practice often leads to overcharging of the connected battery. Secondly, in an attempt to deliver quick service and satisfy the customer’s expected time of need, they sometimes, adjust the charging setting of the charger to increase the charging current so as to reduce the charging time in order to get the battery charged within a short time. This kind of practice shortens the life span of the battery. However, these common problems had suggested the development and construction of a 12V portable battery charger with built-in automatic charging cut-off circuit in order to encourage domestic usage. This would help automobile drivers to avoid charging problems associated with commercial services centers (Bangaru, at al, 2013).

Some components like a protection fuse and current reverse prevention diode were considered during development of this product to prevent problems that may result from short circuit current and reverse current.

Considering, the compact shape of the battery charger, with very low ventilation an extractor fan was incorporated to drive away hot air and moisture that would be generated inside the charger compartment during operation (Bangaru, at al, 2013).

1.2     Statement of the problem

A simple 12volts charger works by supplying a constant DC or pulsed DC power source to a battery being charged. The simple charger does not alter its output based on time or the charge on the battery. This simplicity means that a simple charger is inexpensive. The circuit of a battery charger has the ability to convert voltages from one form to another (usually AC to DC voltages). This process is carried out through the use of some important components like: rectifiers, capacitor to filter and remove ripples from the AC source and a voltage regulator (IC). However, this project is based on the construction of a 24V/12volts simple battery charger with local materials to reduce cost. The proposed project design works on 24V/12V batteries. There is resistance connected in the battery charger to limit the short circuit current.

1.3     Aim and Objectives of the study

The aim of this project work is to design, construct and demonstrate how a simple 24V/12volts battery charger works.

The specifics objectives are as follows:

• To design a device that will recharge 24V/12v lead acid battery when discharged.
• To design a device that has the ability to indicate charging process, low battery and fully charge levels through LED indicators.
• To design and construct a battery charger that can be use to charge any kind of 24V/12V rechargeable batteries including alkaline, NiCad or lead acid batteries.

1.4     Significance of the study

A simple 24V/12volt battery charger is a simple circuit that comprises of different component that are soldered together on a circuit board to give or produce a require function. Therefore, the importance of this project work is to aid both technicians and students on how to construct a simple battery charger circuit and how it works. It is hoped that after the construction of this charger circuit, it will be kept on the laboratory to be used for battery charging and for practicals and other academic functions.

1.5     Scope of the Study

This project work is limited to the construction and demonstration of a simple battery charger of 24V/12volts. The circuit input voltage is 240volts from the A.C supply mains which will be stepped down by a step-down transformer to 12volts. The 12volts A.C is rectified through a bridge rectifier and filtered through capacitor connected in parallel from the positive terminal of the bridge rectifier. The output voltage is used to charge a battery. The project is limited to 24V/12V batteries. It is not advisable to use on rechargeable batteries outside 24V/12V.

1.6     Limitation of the Study

During the project work, the researcher encountered the following problems which in one way or the other have prevented him from completing the work at the usually time. These include: financial problems, time factor and unavailability of material which the researcher have to move from far distance area in search of textbooks and other important materials.

1.7     Relevance of the Study

1. It helps to prolong the lifespan of the battery
2. It minimizes damage of the battery and other components.

1.8     Report Organization

This project work is organized in the following order.

Chapter one: Chapter one is introduction to the research/project. This chapter is all about the problems which the project intends to solve and the means through which it can be solved. The relevance of the project, the scope of the project and finally it’s limitations.

Chapter two: This chapter is the literature review. It reviews the relevant works other researchers have done in the field of overhead protection and the problems they are having in those researchers. It also reviews the available technology through which the project can be realized and also the characteristics of the components used.

Chapter three: This chapter deals with the methodology and design of the system. The most important aspect of this chapter is the block diagram of the system. The mathematical analysis was also carried out here to determine the components on each block.

Chapter four: This chapter is all about the system implementation and results of texts carried out on the system. The bill of engineering measurement and evaluation (BEME) was also carried out here.

Chapter five: Chapter five is the conclusion and recommendations. It summarizes the research which was done, the result gotten.

Pages:  77

Category: Project

Format:  Word & PDF               

Chapters: 1-5                                          

Source: Imsuinfo

Material contains Table of Content, Abstract and References.