Regenerative Braking System

REGENERATIVE BRAKING SYSTEM

PROJECT REPORT ONREGENERATIVE BRAKING

SYSTEM

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REGENERATIVE BRAKING SYSTEM

contents

Abstract 04

Project Guidance 07

Introduction to the project 08

Working principle 10

Hardware Components 11

PIN Description 23

Battery 28

Battery Lifetime 48

IR Sensors 53

Brakes 59

Chain 65

Sprocket 71

Application 77

Future Study 77

Final Kit 78

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REGENERATIVE BRAKING SYSTEM

PROJECT REPORT

ON

REGENERATIVE BRAKING SYSTEM

ABSTRACT

The system will generate electrical energy while the wheel is about is stop when applying

brakes. The model comprises a moving wheel arrangement with induction braking system that

create regeneration of electrical energy to charge the battery. In a regenerative braking system,

the electric motor that is responsible for all or part of an electric or hybrid-electric vehicle’s

propulsion & also does most of the braking. When the driver steps on the brake pedal, instead of

activating a conventional friction-based braking process, it sends an electronic signal to the

electric motor, directing it to run in reverse mode, which creates resistance to slow the vehicle

through a process that is analogous to down-shifting a standard transmission vehicle.

  Regenerative Braking System is the way of slowing vehicle by using the motors as

brakes. Instead of the surplus energy of the vehicle being wasted as unwanted heat, the motors

act as generators and return some of it to the overhead wires as electricity. The vehicle is

primarily powered from the electrical energy generated from the generator, which burns

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REGENERATIVE BRAKING SYSTEM

gasoline. This energy is stored in a large battery, and used by an electric motor that provides

motive force to the wheels. The regenerative braking taking place on the vehicle isa way to

obtain more efficiency; instead of converting kinetic energy to thermal energy through frictional

braking, the vehicle can convert a good fraction of its kinetic energy back into charge in the

battery, using the same principle as an alternator.

Regenerative Braking System is the way of slowing vehicle by using the motors as

brakes. Instead of the surplus energy of the vehicle being wasted as unwanted heat, the motors

act as generators and return some of it to the overhead wires as electricity. The vehicle is

primarily powered from the electrical energy generated from the generator, which burns

gasoline. This energy is stored in a large battery, and used by an electric motor that provides

motive force to the wheels. The regenerative braking taking place on the vehicle isa way to

obtain more efficiency; instead of converting kinetic energy to thermal energy through frictional

braking, the vehicle can convert a good fraction of its kinetic energy back into charge in the

battery, using the same principle as an alternator

Definition:

Braking method in which the mechanical energy from the load is converted into electric energy

and regenerated back into the line is known as Regenerative Braking. The Motor operates as

generator.

Brake:-

A brake is a machine element and its principle object is to absorb energy during deceleration. In

vehicle brakes are used to absorb kinetic energy whereas in hoists or elevators brakes are also

used

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REGENERATIVE BRAKING SYSTEM

toabsorb potential energy. By connecting the moving member tostationary frame, normally brake 

converts kinetic energy to heatenergy. This causes wastage of energy and also wearing of

frictional lining material

Braking is not total loss:

Conventional brakes apply friction to convert a vehicle’s kineticenergy into heat. In energy

terms, therefore, braking is a total loss: once heat is generated, it is very difficult to reuse. The

regenerative braking system, however, slows a vehicle down in a different way.

WORKING OF REGENERATIVE BRAKING SYSTEM

Working of the regenerative braking system is completely difference from the conventional

braking system. In the traditional braking systems the brake pads rub against the wheels and this

rubbing generates excessive heat. The heat energy produced dissipates into the air, wasting up to

30% of the power generated by the engine. Over a period of time, friction that counteracts the

forward motion and the wasted heat energy reduces the fuel efficiency of the device. Under such

a situation more energy or power output is required so that the energy wasted or lost during

braking can be replaced.

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REGENERATIVE BRAKING SYSTEM

INTRODUCTION OF PROJECT:

The system will generate electrical energy while the wheel is about is stop when applying

brakes. The model comprises a moving wheel arrangement with induction braking system that

create regeneration of electrical energy to charge the battery. In a regenerative braking system,

the electric motor that is responsible for all or part of an electric or hybrid-electric vehicle’s

propulsion, also does most of the braking. When the driver steps on the brake pedal, instead of

activating a conventional friction-based braking process, it sends an electronic signal to the

electric motor, directing it to run in reverse mode, which creates resistance to slow the vehicle

through a process that is analogous to down-shifting a standard transmission vehicle.

 Regenerative Braking System is the way of slowing vehicle by using the motors as

brakes. Instead of the surplus energy of the vehicle being wasted as unwanted heat, the motors

act as generators and return some of it to the overhead wires as electricity. The vehicle is

primarily powered from the electrical energy generated from the generator, which burns

gasoline. This energy is stored in a large battery, and used by an electric motor that provides

motive force to the wheels. The regenerative braking taking place on the vehicle isa way to

obtain more efficiency; instead of converting kinetic energy to thermal energy through frictional

braking, the vehicle can convert a good fraction of its kinetic energy back into charge in the

battery, using the same principle as an alternator.

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BLOCK DIAGRAM:

a b

NOTE:

MOTOR 1: To rotate engine wheel.

MOTOR 2: Electrical power generator.

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BATTERY

MOTOR1

IR SENSORS

MOTOR DRIVER

MOTOR 2

BRAKESVEHICLE

REGENERATIVE BRAKING SYSTEM

Case a: Brakes applied, IR Receiver receives low signal and drives motor2 with the help of

motor driver circuit.

Case b: Brakes not applied, IR Receiver receives high signal and motor2 does not rotate.

WORKING PRINCIPLE:

Working of the regenerative braking system is completely difference from the

conventional braking system. In the traditional braking systems the brake pads rub against the

wheels and this rubbing generates excessive heat. The heat energy produced dissipates into the

air, wasting up to 30% of the power generated by the car’s engine. Over a period of time, friction

that counteracts the forward motion and the wasted heat energy reduces the fuel efficiency of the

car. Under such a situation more energy or power output is required so that the energy wasted or

lost during braking can be replaced.

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REGENERATIVE BRAKING SYSTEM

SCOPE OF THE PAPER:

Regenerative braking just as waste recycling conserves natural resources by reusing

materials such as glass, aluminum, plastics, and newsprint, an emerging technology called

regenerative braking makes it possible to harvest and reuse as much as 30% of the energy that is

consumed to propel a vehicle.

This emission-free stored electrical energy is then available to assist acceleration, power the air

conditioner, operate power steering, or perform other functions, reducing ic engine fuel

consumption and its accompanying emissions.

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REGENERATIVE BRAKING SYSTEM

An electric motor running backwards also acts as an electric energy generator or dynamo that

can convert the kinetic energy of motion into electrical energy that can be stored for future use.

As an added bonus, regenerative braking with an electric motor takes most of the load off

mechanical brakes, reducing brake maintenance and replacement expense.

HARDWARE COMPONENTS

L293D Driver IC

MOTORS

IR SENSORS

7805 REGULATOR

RESISTORS

CAPACITORS

BATTERY

BRAKE

CHAIN

SPROCKET

APPLICATIONS:

FOUR WHEELERS

INDUSTRIES

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DC MOTORS:

A DC motor is a mechanically commutated electric motor powered from direct current DC). The

stator is stationary in space by definition and therefore so is its current. The current in the rotor is

switched by the commutator to also be stationary in space. This is how the relative angle

between the stator and rotor magnetic flux is maintained near 90 degrees, which generates the

maximum torque.

DC motors have a rotating armature winding (winding in which a voltage is induced) but non-

rotating armature magnetic field and a static field winding (winding that produce the main

magnetic flux) or permanent magnet. Different connections of the field and armature winding

provide different inherent speed/torque regulation characteristics. The speed of a DC motor can

be controlled by changing the voltage applied to the armature or by changing the field current.

The introduction of variable resistance in the armature circuit or field circuit allowed speed

control. Modern DC motors are often controlled by power electronics systems called DC drives.

The introduction of DC motors to run machinery eliminated the need for local steam or internal

combustion engines, and line shaft drive systems. DC motors can operate directly from

rechargeable batteries, providing the motive power for the first electric vehicles. Today DC

motors are still found in applications as small as toys and disk drives, or in large sizes to operate

steel rolling mills and paper machines.

Brush:

A brushed DC electric motor generating torque from DC power supply by using internal

mechanical commutation, space stationary permanent magnets form the stator field. Torque is

produced by the principle of Lorentz force, which states that any current-carrying conductor

placed within an external magnetic field experiences a force known as Lorentz force. The actual

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(Lorentz) force ( and also torque since torque is F x l where l is rotor radius) is a function for

rotor angle and so the green arrow/vector actually changes length/magnitude with angle known

as torque ripple) Since this is a single phase two pole motor the commutator consists of a split

ring, so that the current reverses each half turn ( 180 degrees).

The brushed electric motor generates torque directly from DC power supplied to the motor by

using internal commutation, stationary magnets and rotating electrical magnets.

Like all electric motors or generators, torque is produced by the principle of Lorentz force, which

states that any current-carrying conductor placed within an external magnetic field experiences a

torque or force known as Lorentz force. Advantages of a brushed DC motor include low initial

cost, high reliability, and simple control of motor speed. Disadvantages are high maintenance

and low life-span for high intensity uses. Maintenance involves regularly replacing the brushes

and springs which carry the electric current, as well as cleaning or replacing the commutator.

These components are necessary for transferring electrical power from outside the motor to the

spinning wire windings of the rotor inside the motor. Brushes are made of conductors.

Brushless:

Typical brushless DC motors use a rotating permanent magnet in the rotor, and stationary

electrical current/coil magnets on the motor housing for the rotor, but the symmetrical opposite is

also possible. A motor controller converts DC to AC .This design is simpler than that of brushed

motors because it eliminates the complication of transferring power from outside the motor to the

spinning rotor. Advantages of brushless motors include long life span, little or no maintenance,

and high efficiency. Disadvantages include high initial cost, and more complicated motor speed

controllers. Some such brushless motors are sometimes referred to as "synchronous motors"

although they have no external power supply to be synchronized with, as would be the case with

normal AC synchronous motors.

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Uncommutated:

Other types of DC motors require no commutation.

HOMOPOLAR MOTOR– A homopolar motor has a magnetic field along the axis of

rotation and an electric current that at some point is not parallel to the magnetic field. The

name homopolar refers to the absence of polarity change.

Homopolar motors necessarily have a single-turn coil, which limits them to very low voltages.

This has restricted the practical application of this type of motor.

BALL BEARING MOTOR– A ball bearing motor is an unusual electric motor that

consists of two ball bearing-type bearings, with the inner races mounted on a common

conductive shaft, and the outer races connected to a high current, low voltage power

supply. An alternative construction fits the outer races inside a metal tube, while the inner

races are mounted on a shaft with a non-conductive section (e.g. two sleeves on an

insulating rod). This method has the advantage that the tube will act as a flywheel. The

direction of rotation is determined by the initial spin which is usually required to get it

going.

DC motors are configured in many types and sizes, including brush less, servo, and gear

motor types. A motor consists of a rotor and a permanent magnetic field stator. The

magnetic field is maintained using either permanent magnets or electromagnetic

windings. DC motors are most commonly used in

Variable speed and torque.

Motion and controls cover a wide range of components that in some way are used to

generate and/or control motion. Areas within this category include bearings and bushings,

clutches and brakes, controls and drives, drive components, encoders and resolves,

Integrated motion control, limit switches, linear actuators, linear and rotary motion

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components, linear position sensing, motors (both AC and DC motors), orientation

position sensing, pneumatics and pneumatic components, positioning stages, slides and

guides, power transmission (mechanical), seals, slip rings, solenoids, springs.

Motors are the devices that provide the actual speed and torque in a drive system. 

This family includes AC motor types (single and multiphase motors, universal, servo

motors, induction, synchronous, and gear motor) and DC motors (brush less, servo motor,

and gear motor) as well as linear, stepper and air motors, and motor contactors and

starters.

In any electric motor, operation is based on simple electromagnetism. A current-

carrying conductor generates a magnetic field; when this is then placed in an external

magnetic field, it will experience a force proportional to the current in the conductor, and

to the strength of the external magnetic field. As you are well aware of from playing with

magnets as a kid, opposite (North and South) polarities attract, while like polarities

(North and North, South and South) repel. The internal configuration of a DC motor is

designed to harness the magnetic interaction between a current-carrying conductor and an

external magnetic field to generate rotational motion.

Let's start by looking at a simple 2-pole DC electric motor (here red represents a magnet

or winding with a "North" polarization, while green represents a magnet or winding with

a "South" polarization).

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Every DC motor has six basic parts -- axle, rotor (a.k.a., armature), stator, commutator,

field magnet(s), and brushes. In most common DC motors (and all that Beamers will see),

the external magnetic field is produced by high-strength permanent magnets1. The stator

is the stationary part of the motor -- this includes the motor casing, as well as two or more

permanent magnet pole pieces. The rotor (together with the axle and attached

commutator) rotates with respect to the stator. The rotor consists of windings (generally

on a core), the windings being electrically connected to the commutator. The above

diagram shows a common motor layout -- with the rotor inside the stator (field) magnets.

The geometry of the brushes, commutator contacts, and rotor windings are such

that when power is applied, the polarities of the energized winding and the stator

magnet(s) are misaligned, and the rotor will rotate until it is almost aligned with the

stator's field magnets. As the rotor reaches alignment, the brushes move to the next

commutator contacts, and energize the next winding. Given our example two-pole motor,

the rotation reverses the direction of current through the rotor winding, leading to a "flip"

of the rotor's magnetic field, and driving it to continue rotating.

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In real life, though, DC motors will always have more than two poles (three is a very

common number). In particular, this avoids "dead spots" in the commutator. You can

imagine how with our example two-pole motor, if the rotor is exactly at the middle of its

rotation (perfectly aligned with the field magnets), it will get "stuck" there. Meanwhile,

with a two-pole motor, there is a moment where the commutator shorts out the power

supply (i.e., both brushes touch both commutator contacts simultaneously). This would

be bad for the power supply, waste energy, and damage motor components as well.

Yet another disadvantage of such a simple motor is that it would exhibit a high amount of

torque” ripple" (the amount of torque it could produce is cyclic with the position of the

rotor).

So since most small DC motors are of a three-pole design, let's tinker with the workings of one

via an interactive animation (JavaScript required):

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You'll notice a few things from this -- namely, one pole is fully energized at a time (but

two others are "partially" energized). As each brush transitions from one commutator

contact to the next, one coil's field will rapidly collapse, as the next coil's field will

rapidly charge up (this occurs within a few microsecond). We'll see more about the

effects of this later, but in the meantime you can see that this is a direct result of the coil

windings' series wiring:

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There's probably no better way to see how an average dc motor is put together, than by

just opening one up. Unfortunately this is tedious work, as well as requiring the

destruction of a perfectly good motor.

This is a basic 3-pole DC motor, with 2 brushes and three commutator contacts.

PWM technique:

A pulse width modulator (PWM) is a device that may be used as an efficient light

dimmer or DC motor speed controller. A PWM works by making a square wave with a

variable on-to-off ratio; the average on time may be varied from 0 to 100 percent. In this

manner, a variable amount of power is transferred to the load. The main advantage of a

PWM circuit over a resistive power controller is the efficiency, at a 50% level, the PWM

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REGENERATIVE BRAKING SYSTEM

will use about 50% of full power, almost all of which is transferred to the load, a resistive

controller at 50% load power would consume about 71% of full power, 50% of the power

goes to the load and the other 21% is wasted heating the series resistor. Load efficiency is

almost always a critical factor in solar powered and other alternative energy systems. One

additional advantage of pulse width modulation is that the pulses reach the full supply

voltage and will produce more torque in a motor by being able to overcome the internal

motor resistances more easily. Finally, in a PWM circuits, common small potentiometers

may be used to control a wide variety of loads whereas large and expensive high power

variable resistors are needed for resistive controllers.

Pulse width modulation consists of three signals, which are modulated by a square

wave. The duty cycle or high time is proportional to the amplitude of the square wave.

The effective average voltage over one cycle is the duty cycle times the peak-to-peak

voltage. Thus, the average voltage follows a square wave. In fact, this method depends on

the motor inductance to integrate out the PWM frequency.

A very simply off line motor drive can be built using a TRIAC and a control IC. This

circuit can control the speed of a universal motor. A universal motor is a series wound

DC motor. The circuit uses phase angle control to vary the effective motor voltage.

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A micro controller can also be used to control a triac. A PNP of transistor may be used to

drive the triac. As shown, the MCU ground is connected to the AC line. The gate trigger

current is lower if instead the MCU 5V supply is connected to the AC line. The MCU

must have some means of detecting zero crossing and a timer, which can control the triac

firing. A general-purpose timer with one input capture and one output compare makes an

ideal phase angle control.

L293D DRIVER CIRCUIT:

L293D is a dual H-bridge motor driver integrated circuit (IC). Motor drivers act as

current amplifiers since they take a low-current control signal and provide a higher-

current signal. This higher current signal is used to drive the motors.L293D

contains two inbuilt H-bridge driver circuits. In its common mode of operation, two DC

motors can be driven simultaneously, both in forward and reverse direction. The motor

operations of two motors can be controlled by input logic at pins 2 & 7 and 10 & 15.

Input logic 00 or 11 will stop the corresponding motor. Logic 01 and 10 will rotate it in

clockwise and anticlockwise directions, respectively.

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Enable pins 1 and 9 (corresponding to the two motors) must be high for motors to start

operating. When an enable input is high, the associated driver gets enabled. As a result,

the outputs become active and work in phase with their inputs. Similarly, when the enable

input is low, that driver is disabled, and their outputs are off and in the high-impedance

state. 

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PIN DESCRIPTION: 

 Pin No  Function  Name

1 Enable pin for Motor 1; active high Enable 1,2

2 Input 1 for Motor 1 Input 1

3 Output 1 for Motor 1 Output 1

4 Ground (0V) Ground

5 Ground (0V) Ground

6 Output 2 for Motor 1 Output 2

7 Input 2 for Motor 1 Input 2

8 Supply voltage for Motors; 9-12V (up to 36V)  Vcc 2

9 Enable pin for Motor 2; active high Enable 3,4

10 Input 1 for Motor 1 Input 3

11 Output 1 for Motor 1 Output 3

12 Ground (0V) Ground

13 Ground (0V) Ground

14 Output 2 for Motor 1 Output 4

15 Input2 for Motor 1 Input 4

16 Supply voltage; 5V (up to 36V) Vcc 1

RESISTORS:

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A Resistor is a heat-dissipating element and in the electronic circuits it is mostly used for

either controlling the current in the circuit or developing a voltage drop across it, which could be

utilized for many applications. There are various types of resistors, which can be classified

according to a number of factors depending upon:

Material used for fabrication

Wattage and physical size

Intended application

Ambient temperature rating

Cost

Basically the resistor can be split in to the following four parts from the construction view point.

(1) Base

(2) Resistance element

(3) Terminals

(4) Protective means.

The following characteristics are inherent in all resistors and may be controlled by design

considerations and choice of material i.e. Temperature co–efficient of resistance, Voltage co–

efficient of resistance, high frequency characteristics, power rating, tolerance & voltage rating of

resistors. Resistors may be classified as

(1) Fixed

(2) Semi variable

(3) Variable resistor.

CAPACITORS

The fundamental relation for the capacitance between two flat plates separated by a

dielectric material is given by:-

C=0.08854KA/D

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Where: -

C= capacitance in pf.

K= dielectric constant

A=Area per plate in square cm.

D=Distance between two plates in cm

Design of capacitor depends on the proper dielectric material with particular type of

application. The dielectric material used for capacitors may be grouped in various classes like

Mica, Glass, air, ceramic, paper, Aluminum, electrolyte etc. The value of capacitance never

remains constant. It changes with temperature, frequency and aging. The capacitance value

marked on the capacitor strictly applies only at specified temperature and at low frequencies.

LED (Light Emitting Diodes):

As its name implies it is a diode, which emits light when forward biased. Charge carrier

recombination takes place when electrons from the N-side cross the junction and recombine with

the holes on the P side. Electrons are in the higher conduction band on the N side whereas holes

are in the lower valence band on the P side. During recombination, some of the energy is given

up in the form of heat and light. In the case of semiconductor materials like Gallium arsenide

(GaAs), Gallium phosphate (Gap) and Gallium arsenide phosphate (GaAsP) a greater percentage

of energy is released during recombination and is given out in the form of light. LED emits no

light when junction is reverse biased.

LM7812 AND LM7805:

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Features

• Output Current of 1.5A

• Output Voltage Tolerance of 5%

• Internal thermal overload protection

• Internal Short-Circuit Limited

• No External Component

• Output Voltage 5.0V, 6V, 8V, 9V, 10V,

12V, 15V, 18V, 24V

• Offer in plastic TO-252, TO-220 & TO-263

• Direct Replacement for LM78XX

Description:

The Bay Linear LM78XX is integrated linear positive regulator with three terminals. The

LM78XX offer several fixed output voltages making them useful in wide range of applications.

When used as a zener diode/resistor combination

Replacement, the LM78XX usually results in an effective output impedance improvement of two

orders of magnitude, lower quiescent current.

The LM78XX is available in the TO-252, TO-220 & TO-263 Packages

Applications:

• Post regulator for switching DC/DC converter

• Bias supply for analog circuits

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BATTERY:

In our prototype, we use 12v battery and they have variety of uses in our daily

life. From consumer electronics to robotics, from health care products to industries, almost every

second device we use has one battery or the other. Batteries have become an indispensible part of

our lives. We cannot comprehend living without cell phones, torches, laptop computers, music

players like the ipod, but how do we power them up? Answer lies in the battries. Similarly cars

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REGENERATIVE BRAKING SYSTEM

are one of the main modern day necessties which use battries to power the head lamps and

backlights. In electricity, a battery is a device consisting of one or more electromechanical cells

that convert stored chemical energy into electrical energy. Since the invention of the first battery

(or "voltaic pile") in 1800 by Alessandro Volta and especially since the technically improved

Daniell cell in 1836, batteries have become a common power source for many household and

industrial applications. According to a 2005 estimate, the worldwide battery industry generates

US$48 billion in sales each year,[2] with 6% annual growth.

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. Batteries come in many sizes, from

miniature cells used to power hearing aids and wristwatches to battery banks the size of rooms

that provide standby power for telephone exchanges and computer data centers.

A battery is a device that converts chemical energy directly to electrical energy It consists of a

number of voltaic cells; each voltaic cell consists of two half-cells connected in series by a

conductive electrolyte containing anions and cations. One half-cell includes electrolyte and the

electrode to which anions (negatively charged ions) migrate, i.e., the anode or negative electrode;

the other half-cell includes electrolyte and the electrode to which cations (positively charged

ions) migrate, i.e., the cathode or positive electrode. In the redox reaction that powers the battery,

cations are reduced (electrons are added) at the cathode, while anions are oxidized (electrons are

removed) at the anode.[23] The electrodes do not touch each other but are electrically connected

by the electrolyte. Some cells use two half-cells with different electrolytes. A separator between

half-cells allows ions to flow, but prevents mixing of the electrolytes.

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Each half-cell has an electromotive force (or emf), determined by its ability to drive electric

current from the interior to the exterior of the cell. The net emf of the cell is the difference

between the emfs of its half-cells, as first recognized by Volta.[12] Therefore, if the electrodes

have emfs and , then the net emf is ; in other words, the net emf is the

difference between the reduction potentials of the half-reactions.

The electrical driving force or across the terminals of a cell is known as the terminal

voltage (difference) and is measured in volts. The terminal voltage of a cell that is neither

charging nor discharging is called the open-circuit voltage and equals the emf of the cell.

Because of internal resistance, the terminal voltage of a cell that is discharging is smaller in

magnitude than the open-circuit voltage and the terminal voltage of a cell that is charging

exceeds the open-circuit voltage. An ideal cell has negligible internal resistance, so it would

maintain a constant terminal voltage of until exhausted, then dropping to zero. If such a cell

maintained 1.5 volts and stored a charge of one coulomb then on complete discharge it would

perform 1.5 joule of work. In actual cells, the internal resistance increases under discharge, and

the open circuit voltage also decreases under discharge. If the voltage and resistance are plotted

against time, the resulting graphs typically are a curve; the shape of the curve varies according to

the chemistry and internal arrangement employed.

As stated above, the voltage developed across a cell's terminals depends on the energy release of

the chemical reactions of its electrodes and electrolyte. Alkaline and zinc–carbon cells have

different chemistries but approximately the same emf of 1.5 volts; likewise NiCd and NiMH

cells have different chemistries, but approximately the same emf of 1.2 volts. On the other hand

the high electrochemical potential changes in the reactions of lithium compounds give lithium

cells emfs of 3 volts or more.

This entire power requirement means that we need a robust, portable and an efficient source of

power. There are a couple of factors one has to look out while choosing the type of 12v battery.

Because a twelve volt battery can be of many types, sizes, form factors, and materials. 12 volt is

just the rating of the battery and it does not specify something physical. Batteries are also

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available in other voltage ratings such as 24, 9 and 5 volt. Its rather a quantity. There are many

types of batteries depending upon the construction. 

12 volt lead acid batteries:

One of the most common type of 12V battery is the 12v lead acid battery. It is a dc battery with

lead terminals and an acid, usually hydrochloric acid is used as an electrolyte in lead acid battery.

It is the battery of choice for cars, trucks, tanks, uninterrupted power supplies and other vehicles.

12V lead acid battery is used in cars as there is no risk of handling in cars. 12volt lead acid

battery is also used in battery banks and backup systems at power sensitive systems, such as

telecom switches, like any other 12v dc battery because it’s a source of dc 12volt power.

Lead acid 12V battery is rarely used in home appliances and uses. For example, computer UPS'

rarely use lead acid battery as it is not very easy to handle and can cause potential hazards, such

as a fire etc. Home users generally prefer a solid state battery such as the one used in dry cells

over 12v lead acid batteries or rechargeable battery which provides 12volt power . Those are

found in torch lights, calculators, watches, clocks and toys.

12v Battery Construction:

In a 12 volt lead acid battery, usually hydrochloric acid is used as an electrolyte in lead acid

battery. The casing is usually made up of plastic, rubber or any other hard material in order to

avoid the acid housed inside. Inside, it is made of upmany small cells. Metals are used for

cathodes and anodes (negative and positive terminals respectively for the 12Volt Battery.

12 volt lead acid battery is the 12 volt dc battery  for cars, trucks, tanks, uninterrupted power

supplies and other vehicles. This type of battery is also used in battery banks and backup systems

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at power sensitive systems, such as telecom switches.

It is 12v dc battery but is not a portable 12v battery or 12v rechargeable battery and 12v battery

pack due to its size and handling issues. For example, computer UPS' rarely use lead acid battery

as it is not very easy to handle and can cause potential hazards, such as a fire etc.

Lead acid batteries used in the RV and Marine Industries usually consist of two 6-volt

batteries in series, or a single 12-volt battery. These batteries are constructed of several single

cells connected in series each cell produces approximately 2.1 volts. A six-volt battery has three

single cells, which when fully charged produce an output voltage of 6.3 volts. A twelve-volt

battery has six single cells in series producing a fully charged output voltage of 12.6 volts.

A battery cell consists of two lead plates a positive plate covered with a paste of lead dioxide and

a negative made of sponge lead, with an insulating material (separator) in between. The plates

are enclosed in a plastic battery case and then submersed in an electrolyte consisting of water and

sulfuric acid (see figure # 1). Each cell is capable of storing 2.1 volts.

In order for lead acid cell to produce a voltage, it must first receive a (forming) charge

voltage of at least 2.1-volts/cell from a charger. Lead acid batteries do not generate voltage on

their own; they only store a charge from another source. This is the reason lead acid batteries are

called storage batteries, because they only store a charge. The size of the battery plates and

amount of electrolyte determines the amount of charge lead acid batteries can store. The size of

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this storage capacity is described as the amp hour (AH) rating of a battery. A typical 12-volt

battery used in a RV or marine craft has a rating 125 AH, which means it can supply 10 amps of

current for 12.5 hours or 20-amps of current for a period of 6.25 hours. Lead acid batteries can

be connected in parallel to increase the total AH capacity.

In figure # 2 below, six single 2.1-volt cells have been connected in series to make the typical

12-volt battery, which when fully charged will produce a total voltage of 12.6-volts.

Lead Acid Batter Discharge Cycle

In figure # 3, above a fully charged battery is connected to a load (light bulb) and the chemical

reaction between sulfuric acid and the lead plates produces the electricity to light the bulb. This

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chemical reaction also begins to coat both positive and negative plates with a substance called

lead sulfate also known as sulfation (shown as a yellow build-up on plates). This build-up of lead

sulfate is normal during a discharge cycle. As the battery continues to discharge, lead sulfate

coats more and more of the plates and battery voltage begins to decrease from fully charged state

of 12.6-volts (figure # 4).

In figure # 5 the battery is now fully discharged, the plates are almost completely covered with

lead sulfate (sulfation) and voltage has dropped to 10.5-volts.

NOTE: Discharging a lead acid battery below 10.5 volts will severely damage it!

Lead sulfate (sulfation) now coats most of the battery plates. Lead sulfate is a soft material,

which can is reconverted back into lead and sulfuric acid, provided the discharged battery is

immediately connected to a battery charger. If a lead acid battery is not immediately recharged,

the lead sulfate will begin to form hard crystals, which can not be reconverted by a standard

fixed voltage (13.6 volts) battery converter/charger.

NOTE: Always recharge your RV or Marine battery as soon as possible to prevent loss of battery

capacity due to the build-up of hard lead sulfate crystals!

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Lead Acid Battery Recharge Cycle:

The most important thing to understand about recharging lead acid batteries is that a

converter/charger with a single fixed output voltage will not properly recharge or maintain your

battery. Proper recharging and maintenance requires an intelligent charging system that can vary

the charging voltage based on the state of charge and use of your RV or Marine battery.

Progressive Dynamics has developed intelligent charging systems that solve battery problems

and reduce battery maintenance.

The discharged battery shown in figure # 6 on the next page is connected to a converter/charger

with its output voltage set at 13.6-volts. In order to recharge a 12-volt lead acid battery with a

fully charged terminal voltage of 12.6-volts, the charger voltage must be set at a higher voltage.

During the recharging process as electricity flows through the water portion of the electrolyte

and water, (H2O) is converted into its original elements, hydrogen and oxygen. These gasses are

very flammable and the reason your RV or Marine batteries must be vented outside. Gassing

causes water loss and therefore lead acid batteries need to have water added periodically. Sealed

lead acid batteries contain most of these gasses allowing them to recombine into the electrolyte.

If the battery is overcharged pressure from these gasses will cause relief caps to open and vent,

resulting in some water loss. Most sealed batteries have extra electrolyte added during the

manufacturing process to compensate for some water loss.

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The battery shown in figure # 7 above has been fully recharged using a fixed charging voltage of

13.6-volts. Notice that some lead sulfate (sulfation) still remains on the plates. This build-up will

continue after each recharging cycle and gradually the battery will begin to loose capacity to

store a full charge and eventually must be replaced. Lead sulfate build up is reduced if battery is

given an Equalizing Charge once every 10 discharge cycles or at least once a month. An

Equalizing Charge increases charging voltage to 14.4 volts or higher for a short period. This

higher voltage causes gassing that equalizes (re-mixes) the electrolyte solution.

Since most RV and Marine craft owners seldom remember to perform this function, Progressive

Dynamics has developed the microprocessor controlled Charge Wizard. The Charge Wizard will

automatically provide an Equalizing Charge every 21 hours for a period of 15 minutes, when the

battery is fully charged and not in use. Our 2000 Series of Marine Battery Chargers have the

Charge Wizard feature built-in.

One disadvantage of recharging a lead acid battery at a fixed voltage of 13.6-volts is the recharge

time is very long. A typical 125-AH RV or Marine battery will take approximately 80 hours to

recharge at 13.6 volts. Increasing the charge voltage to 14.4-volts will reduce battery recharge

time for a 125-AH battery to 3-4 hours. Once a battery reaches 90% of full charge, the voltage

must be reduced from 14.4-volts to 13.6-volts to reduce gassing and water loss. The optional

Charge Wizard automatically senses when a battery has a very low state of charge and

automatically selects its BOOST MODE of operation. BOOST MODE increases the voltage of a

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PD9100 Series converter/charger to 14.4 volts. When the battery reaches the 90% charge level,

the Charge Wizard automatically reduces the charge voltage down to 13.6 volts to complete the

charge. Again, this is a standard feature on our Marine Chargers.

Another disadvantage of recharging a lead acid battery at a fixed voltage of 13.6-volts is that

once it is fully charged, 13.6 volts will cause considerable gassing and water loss. To prevent this

from occurring the charging voltage must be reduced to 13.2-volts. The Charge Wizard will

automatically select its STORAGE MODE of operation (13.2-volts) once the battery reaches full

charge and remains unused for a period of 30 hours. This feature is standard on all of Progressive

Dynamics Marine Battery Chargers.

At a charging voltage of 13.2 volts, the converter/charger will maintain a full charge, reduce

gassing and water loss. However, this lower voltage does not provide enough gassing to prevent

a battery condition called Battery Stratification. Battery Stratification is caused by the fact that

the electrolyte in the battery is a mixture of water and acid and, like all mixtures, one component,

the acid, is heavier than water. Therefore, acid will begin to settle and concentrate at the bottom

of the battery (see figure #8).

Most converter/chargers on the market are set at approximately 13.6-volts. During the battery

recharge cycle lead sulfate (sulfation) begins to reconvert to lead and sulfuric acid.

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This higher concentration of acid at the bottom of the battery causes additional build-up of lead

sulfate (sulfation), which reduces battery storage capacity and battery life. In order to prevent

Battery Stratification, an Equalization Charge (increasing charging voltage to 14.4-volts) must be

applied periodically. The Charge Wizard automatically selects its EQUALIZATION MODE

(14.4 volts) every 21 hours for a period of 15 minutes. This Equalizing Charge feature is

standard on our Marine chargers.

As you have learned, in order to properly charge and maintain a lead acid battery you must use

an intelligent charging system. Progressive Dynamics, Inteli-Power 9100 Series RV converters

with a Charge Wizard installed, or one of our Inteli-Power Marine Battery Chargers will provide

the intelligent charging system your battery needs for a long life, with low maintenance.

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Categories and types of batteries

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List of battery types:

From top to bottom: a large 4.5-volt (3R12) battery, a D Cell, a C cell, an AA cell, an AAA cell,

an AAAA cell, an A23 battery, a 9-volt PP3 battery, and a pair of button cells (CR2032 and

LR44).

Batteries are classified into two broad categories, each type with advantages and disadvantages.

Primary batteries irreversibly (within limits of practicality) transform chemical energy to

electrical energy. When the initial supply of reactants is exhausted, energy cannot be

readily restored to the battery by electrical means.

Secondary batteries can be recharged; that is, they can have their chemical reactions

reversed by supplying electrical energy to the cell, restoring their original composition.

Some types of primary batteries used, for example, for telegraph circuits, were restored to

operation by replacing the components of the battery consumed by the chemical reaction.

Secondary batteries are not indefinitely rechargeable due to dissipation of the active materials,

loss of electrolyte and internal corrosion.

Primary batteries:

Primary cell

Primary batteries can produce current immediately on assembly. Disposable batteries are

intended to be used once and discarded. These are most commonly used in portable devices that

have low current drain, are used only intermittently, or are used well away from an alternative

power source, such as in alarm and communication circuits where other electric power is only

intermittently available. Disposable primary cells cannot be reliably recharged, since the

chemical reactions are not easily reversible and active materials may not return to their original

forms. Battery manufacturers recommend against attempting to recharge primary cells

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Common types of disposable batteries include zinc–carbon batteries and alkaline batteries. In

general, these have higher energy densities than rechargeable batteries, but disposable batteries

do not fare well under high-drain applications with loads under 75 ohms (75 Ω).

Secondary batteries:

Rechargeable battery

Secondary batteries must be charged before use; they are usually assembled with active materials

in the discharged state. Rechargeable batteries or secondary cells can be recharged by applying

electric current, which reverses the chemical reactions that occur during its use. Devices to

supply the appropriate current are called chargers or rechargers.

The oldest form of rechargeable battery is the lead–acid battery. This battery is notable in that it

contains a liquid in an unsealed container, requiring that the battery be kept upright and the area

be well ventilated to ensure safe dispersal of the hydrogen gas produced by these batteries during

overcharging. The lead–acid battery is also very heavy for the amount of electrical energy it can

supply. Despite this, its low manufacturing cost and its high surge current levels make its use

common where a large capacity (over approximately 10 Ah) is required or where the weight and

ease of handling are not concerns.

A common form of the lead–acid battery is the modern car battery, which can, in general, deliver

a peak current of 450 amperes. An improved type of liquid electrolyte battery is the sealed valve

regulated lead–acid battery (VRLA battery), popular in the automotive industry as a replacement

for the lead–acid wet cell. The VRLA battery uses an immobilized sulfuric acid electrolyte,

reducing the chance of leakage and extending shelf life. VRLA batteries have the electrolyte

immobilized, usually by one of two means:

Gel batteries (or "gel cell") contain a semi-solid electrolyte to prevent spillage.

Absorbed Glass Mat (AGM) batteries absorb the electrolyte in a special fiberglass

matting.

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Other portable rechargeable batteries include several "dry cell" types, which are sealed units and

are, therefore, useful in appliances such as mobile phones and laptop computers. Cells of this

type (in order of increasing power density and cost) include nickel–cadmium (NiCd), nickel–zinc

(NiZn), nickel metal hydride (NiMH), and lithium-ion (Li-ion) cells By far, Li-ion has the

highest share of the dry cell rechargeable market. Meanwhile, NiMH has replaced NiCd in most

applications due to its higher capacity, but NiCd remains in use in power tools, two-way radios,

and medical equipment. NiZn is a new technology that is not yet well established commercially.

Recent developments include batteries with embedded electronics such as USBCELL, which

allows charging an AA cell through a USB connector, and smart battery packs with state-of-

charge monitors and battery protection circuits to prevent damage on over-discharge. low self-

discharge (LSD) allows secondary cells to be precharged prior to shipping.

Battery cell types:

There are many general types of electrochemical cells, according to chemical processes applied

and design chosen. The variation includes galvanic cells, electrolytic cells, fuel cells, flow cells

and voltaic piles.

Wet cell:

A wet cell battery has a liquid electrolyte. Other names are flooded cell, since the liquid covers

all internal parts, or vented cell, since gases produced during operation can escape to the air. Wet

cells were a precursor to dry cells and are commonly used as a learning tool for electrochemistry.

It is often built with common laboratory supplies, such as beakers, for demonstrations of how

electrochemical cells work. A particular type of wet cell known as a concentration cell is

important in understanding corrosion. Wet cells may be primary cells (non-rechargeable) or

secondary cells (rechargeable). Originally, all practical primary batteries such as the Daniell cell

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were built as open-topped glass jar wet cells. Other primary wet cells are the Leclanche cell,

Grove cell, Bunsen cell, Chromic acid cell, Clark cell, and Weston cell. The Leclanche cell

chemistry was adapted to the first dry cells. Wet cells are still used in automobile batteries and in

industry for standby power for switchgear, telecommunication or large uninterruptible power

supplies, but in many places batteries with gel cells have been used instead. These applications

commonly use lead–acid or nickel–cadmium cells.

Dry cell:

"Dry cell" redirects here. For the heavy metal band, see Dry Cell (band).

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Line art drawing of a dry cell:

1. brass cap, 2. plastic seal, 3. expansion space, 4. porous cardboard, 5. zinc can, 6. carbon rod, 7.

chemical mixture.

A dry cell has the electrolyte immobilized as a paste, with only enough moisture in it to allow

current to flow. Unlike a wet cell, a dry cell can operate in any orientation without spilling as it

contains no free liquid, making it suitable for portable equipment. By comparison, the first wet

cells were typically fragile glass containers with lead rods hanging from the open top, and

needed careful handling to avoid spillage. Lead–acid batteries did not achieve the safety and

portability of the dry cell until the development of the gel battery.

A common dry cell battery is the zinc–carbon battery, using a cell sometimes called the dry

Leclanché cell, with a nominal voltage of 1.5 volts, the same as the alkaline battery (since both

use the same zinc–manganese dioxide combination).

A standard dry cell comprises a zinc anode (negative pole), usually in the form of a cylindrical

pot, with a carbon cathode (positive pole) in the form of a central rod. The electrolyte is

ammonium chloride in the form of a paste next to the zinc anode. The remaining space between

the electrolyte and carbon cathode is taken up by a second paste consisting of ammonium

chloride and manganese dioxide, the latter acting as a depolariser. In some more modern types of

so-called 'high-power' batteries (with much lower capacity than standard alkaline batteries), the

ammonium chloride is replaced by zinc chloride.

Molten salt:

Molten salt batteries are primary or secondary batteries that use a molten salt as electrolyte. Their

energy density and power density give them potential for use in electric vehicles, but they

operate at high temperatures and must be well insulated to retain heat.

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Reserve:

A reserve battery is stored in unassembled form and is activated, ready-charged, when its internal

parts are assembled, e.g. by adding electrolyte; it can be stored inactivated for a long period of

time. For example, a battery for an electronic fuse might be activated by the impact of firing a

gun, breaking a capsule of electrolyte to activate the battery and power the fuse’s circuits.

Reserve batteries are usually designed for a short service life (seconds or minutes) after long

storage (years). A water-activated battery for oceanographic instruments or military applications

becomes activated on immersion in water.

Battery cell performance:

A battery's characteristics may vary over load cycle, over charge cycle, and over lifetime due to

many factors including internal chemistry, current drain, and temperature.

Capacity and discharging

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A device to check battery voltage

A battery's capacity is the amount of electric charge it can store. The more electrolyte and

electrode material there is in the cell the greater the capacity of the cell. A small cell has less

capacity than a larger cell with the same chemistry, and they develop the same open-circuit

voltage.

Because of the chemical reactions within the cells, the capacity of a battery depends on the

discharge conditions such as the magnitude of the current (which may vary with time), the

allowable terminal voltage of the battery, temperature, and other factors. The available capacity

of a battery depends upon the rate at which it is discharged. If a battery is discharged at a

relatively high rate, the available capacity will be lower than expected.

The capacity printed on a battery is usually the product of 20 hours multiplied by the constant

current that a new battery can supply for 20 hours at 68 F° (20 C°), down to a specified terminal

voltage per cell. A battery rated at 100 A·h will deliver 5 A over a 20-hour period at room

temperature. However, if discharged at 50 A, it will have a lower capacity.

The relationship between current, discharge time, and capacity for a lead acid battery is

approximated (over a certain range of current values) by Peukert's law:

Where

is the capacity when discharged at a rate of 1 amp.

is the current drawn from battery (A).

is the amount of time (in hours) that a battery can sustain.

is a constant around 1.3.

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For low values of I internal self-discharge must be included.

Internal energy losses and limited rate of diffusion of ions through the electrolyte cause the

efficiency of a real battery to vary at different discharge rates. When discharging at low rate, the

battery's energy is delivered more efficiently than at higher discharge rates, but if the rate is very

low, it will partly self-discharge during the long time of operation, again lowering its efficiency.

Installing batteries with different A·h ratings will not affect the operation of a device (except for

the time it will work for) rated for a specific voltage unless the load limits of the battery are

exceeded. High-drain loads such as digital cameras can result in delivery of less total energy, as

happens with alkaline batteries. For example, a battery rated at 2000 mAh for a 10- or 20-hour

discharge would not sustain a current of 1 A for a full two hours as its stated capacity implies.

Crates:

The C-rate signifies a discharge rate relative to the capacity of a battery in one hour. A rate of 1C

would mean an entire 1.6Ah battery would be discharged in 1 hour at a discharge current of

1.6A. A 2C rate would mean a discharge current of 3.2A

Fastest charging, largest, and lightest batteries:

As of 2012 Lithium iron phosphate (LiFePO4) batteries were the fastest-charging and

discharging batteries (super capacitors, in some ways comparable to batteries, charge faster). The

world's largest battery, composed of Ni–Cd cells, was in Fairbanks, Alaska. Sodium–sulfur

batteries were being used to store wind power, Lithium–sulfur batteries have been used on the

longest and highest solar-powered flight. The speed of recharging of lithium-ion batteries can be

increased by manufacturing changes.

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Battery lifetime:

Primary batteries

Disposable (or "primary") batteries typically lose 8 to 20 percent of their original charge every

year at room temperature (20°–30°C This is known as the "self discharge" rate, and is due to

non-current-producing "side" chemical reactions which occur within the cell even if no load is

applied. The rate of the side reactions is reduced if the batteries are stored at lower temperature,

although some batteries can be damaged by freezing. High or low working temperatures may

reduce battery performance. This will affect the initial voltage of the battery. For an AA alkaline

battery, this initial voltage is approximately normally distributed around 1.6 volts.

Discharging performance of all batteries drops at low temperature.

Secondary batteries:

Storage life of secondary batteries is limited by chemical reactions that occur between the battery

parts and the electrolyte; these are called "side reactions". Internal parts may corrode and fail, or

the active materials may be slowly converted to inactive forms. Since the active material on the

battery plates changes chemical composition on each charge and discharge cycle, active material

may be lost due to physical changes of volume; this may limit the cycle life of the battery.

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RECHARGEABLE BATTERIES:

Old chemistry rechargeable batteries self-discharge more rapidly than disposable alkaline

batteries, especially nickel-based batteries; a freshly charged nickel cadmium (NiCd) battery

loses 10% of its charge in the first 24 hours, and thereafter discharges at a rate of about 10% a

month. However, newer low self-discharge nickel metal hydride (NiMH) batteries and modern

lithium designs have reduced the self-discharge rate to a relatively low level (but still poorer than

for primary batteries). Most nickel-based batteries are partially discharged when purchased, and

must be charged before first use Newer NiMH batteries are ready to be used when purchased,

and have only 15% discharge in a year.

Although rechargeable batteries have their energy content restored by charging, some

deterioration occurs on each charge–discharge cycle. Low-capacity NiMH batteries (1700–2000

mA·h) can be charged for about 1000 cycles, whereas high-capacity NiMH batteries (above 2500

mA·h) can be charged for about 500 cycles NiCd batteries tend to be rated for 1000 cycles

before their internal resistance permanently increases beyond usable values. Under normal

circumstances, a fast charge, rather than a slow overnight charge, will shorten battery lifespan.

Also, if the overnight charger is not "smart" and cannot detect when the battery is fully charged,

then overcharging is likely, which also damages the battery. Degradation usually occurs because

electrolyte migrates away from the electrodes or because active material falls off the electrodes.

NiCd batteries suffer the drawback that they should be fully discharged before recharge. Without

full discharge, crystals may build up on the electrodes, thus decreasing the active surface area

and increasing internal resistance. This decreases battery capacity and causes the "memory

effect". These electrode crystals can also penetrate the electrolyte separator, thereby causing

shorts. NiMH, although similar in chemistry, does not suffer from memory effect to quite this

extent. A battery does not suddenly stop working; its capacity gradually decreases over its

lifetime, until it can no longer hold sufficient charge.

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An analog camcorder battery [lithium ion].

Automotive lead–acid rechargeable batteries have a much harder life. Because of vibration,

shock, heat, cold, and sulfation of their lead plates, few automotive batteries last beyond six

years of regular use. Automotive starting (SLI: Starting, Lighting, Ignition) batteries have many

thin plates to provide as much current as possible in a reasonably small package. In general, the

thicker the plates, the longer the life of the battery. They are typically drained only a small

amount before recharge. Care should be taken to avoid deep discharging a starting battery, since

each charge and discharge cycle causes active material to be shed from the plates.

"Deep-cycle" lead–acid batteries such as those used in electric golf carts have much thicker

plates to aid their longevity. The main benefit of the lead–acid battery is its low cost; the main

drawbacks are its large size and weight for a given capacity and voltage. Lead–acid batteries

should never be discharged to below 20% of their full capacity, because internal resistance will

cause heat and damage when they are recharged. Deep-cycle lead–acid systems often use a low-

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charge warning light or a low-charge power cut-off switch to prevent the type of damage that

will shorten the battery's life.

Extending battery life:

Battery life can be extended by storing the batteries at a low temperature, as in a refrigerator or

freezer, which slows the chemical reactions in the battery. Such storage can extend the life of

alkaline batteries by about 5%; rechargeable batteries can hold their charge much longer,

depending upon type. To reach their maximum voltage, batteries must be returned to room

temperature; discharging an alkaline battery at 250 mA at 0°C is only half as efficient as it is at

20°C Alkaline battery manufacturers such as Duracell do not recommend refrigerating batteries.

Imagine a world where everything that used electricity had to be plugged in. Flashlights, hearing

aids, cell phones and other portable devices would be tethered to electrical outlets, rendering

them awkward and cumbersome. Cars couldn't be started with the simple turn of a key; a

strenuous cranking would be required to get the pistons moving. Wires would be strung

everywhere, creating a safety hazard and an unsightly mess. Thankfully, batteries provide us

with a mobile source of power that makes many modern conveniences possible.

While there are many different types of batteries, the basic concept by which they function

remains the same. When a device is connected to a battery, a reaction occurs that produces

electrical energy. This is known as an electrochemical reaction. Italian physicist Count

Alessandro Volta first discovered this process in 1799 when he created a simple battery from

metal plates and brine-soaked cardboard or paper. Since then, scientists have greatly improved

upon Volta's original design to create batteries made from a variety of materials that come in a

multitude of sizes.

Today, batteries are all around us. They power our wristwatches for months at a time. They keep

our alarm clocks and telephones working, even if the electricity goes out. They run our smoke

detectors, electric razors, power drills, mp3 players, thermostats -- and the list goes on. If you're

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reading this article on your laptop or smartphone, you may even be using batteries right now!

However, because these portable power packs are so prevalent, it's very easy to take them for

granted. This article will give you a greater appreciation for batteries by exploring their history,

as well as the basic parts, reactions and processes that make them work. So cut that cord and

click through our informative guide to charge up your knowledge of batteries.

 Disadvantages of 12 volt battery:

The main disadvantage 12volt lead acid is that it has  one of the lowest energy to weight ratio.

This means that this type of 12v battery also has a low energy to volume ratio, which in turn

means that the size of the battery has to be big in order to provide significant amount of power.

Secondly its not portable.

Another major concern about lead acid 12v battery, which is a 12volt power source, is that about

environment. Almost all the batteries used in vehicles are lead acid and this means that the

disposal of these batteries can beome a big hurdle. Since there are alot of cars, this mean alot of

old batteries need to be dumped somewhere and improper disposal means damaged

environment.The automotive industry is now looking for alternatives to replace lead acid battery

in automative applications towards a environmentally safe option

Note : Please do note that the current rating is VERY important. DONOT plug in a battery which

has higher amperage than your modem or router can handle. Most modems and routers are

usually rated at around 1 ampere. So a 12V Battery of that rating should be used.

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IR SENSORS:

IR LED and IR sensor:

IR LED is used as a source of infrared rays. It comes in two packages 3mm or 5mm. 3mm is

better as it is requires less space. IR sensor is nothing but a diode, which is sensitive for infrared

radiation.

This infrared transmitter and receiver is called as IR TX-RX pair. It can be obtained  from

any decent electronics component shop and costs less than 10Rs. Following snap shows 3mm

and 5mm IR pairs. 

Color of IR transmitter and receiver is different. However you may come across pairs

which appear exactly same or even has opposite colors than shown in above pic and it is not

possible to distinguish between TX and RX visually. In case you will have to take help of

multimeter to distinguish between them.

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Principle:

IR LED emits infrared radiation. This radiation illuminates the surface in front of LED.

Surface reflects the infrared light. Depending on reflectivity of the surface, amount of light

reflected varies. This reflected light is made incident on reverse biased IR sensor. When photons

are incident on reverse biased junction of this diode, electron-hole pairs are generated, which

results in reverse leakage current. Amount of electron-hole pairs generated depends on intensity

of incident IR radiation. More intense radiation results in more reverse leakage current. This

current can be passed through a resistor so as to get proportional voltage. Thus as intensity of

incident rays varies, voltage across resistor will vary accordingly.

This voltage can then be given to OPAMP based comparator. Output of the comparator

can be read by uC. Alternatively, you can use on-chip ADC in AVR microcontroller to measure

this voltage and perform comparison in software.

An infrared detector is a detector that reacts to infrared (IR) radiation. The two main

types of detectors are thermal and photonic (photo detectors).

The thermal effects of the incident IR radiation can be followed through many temperature

dependent phenomena. Bolometer and micro bolometer are based on changes in resistance.

Thermocouples and thermopiles use the thermoelectric effect. Golay cells follow thermal

expansion. In IR spectrometers the pyroelectric detectors are the most widespread.

The response time and sensitivity of photonic detectors can be much higher, but usually these

have to be cooled to cut thermal noise. The materials in these are semiconductors with narrow

band gaps. Incident IR photons can cause electronic excitations. In photoconductive detectors,

the resistivity of the detector element is monitored. Photovoltaic detectors contain a p-n junction

on which photoelectric current appears upon illumination. A few detector materials:

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Types:

TYPESPECTRAL

RANGE(ΜM)

WAVENUMBER(CM-

1)

Indium gallium

arsenide(InGaAs)photodiode 0.7-2.6 14300-3800

Germanium photodiode 0.8-1.7 12500-5900

Lead sulfide (PbS) photoconductive 1-3.2 10000-3200

Lead selenide (PbSe) photoconductive 1.5-5.2 6700-1900

Indium antimonide

(InSb)photoconductive 1-6.7 10000-1500

Indium arsenide

(InAs)photovoltaic 1-3.8 10000-2600

Platinum silicide

(PtSi)photovoltaic 1-5 10000-2000

Indium antimonide

(InSb)photodiode 1-5.5 10000-1800

Mercury cadmium

telluride (MCT,

HgCdTe)

photoconductive 0.8-25 12500-400

Mercury zinc

telluride (MZT,

HgZnTe)

photoconductive

Lithium tantalate

(LiTaO3)pyroelectric

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triglycine sulfate

(TGS and DTGS)pyroelectric

The range of pyroelectric detector is determined by the window materials used in their

construction.

Vanadium pentoxide is frequently used as a detector material in uncooled microbolometer

arrays.

Infrared Sensors or IR Sensors:

Infrared radiation is the portion of electromagnetic spectrum having wavelengths longer than

visible light wavelengths, but smaller than microwaves, i.e., the region roughly from 0.75µm to

1000 µm is the infrared region.

Infrared waves are invisible to human eyes. The wavelength region of 0.75µm to 3 µm is called

near infrared, the region from 3 µm to 6 µm is called mid infrared and the region higher than 6

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µm is called far infrared. (The demarcations are not rigid; regions are defined differently by

many). 

There are different types of IR sensors working in various regions of the IR spectrum but the

physics behind "IR sensors" is governed by three laws:

1.         Planck’s radiation law:

Every object at a temperature T not equal to 0 K emits radiation. Infrared radiant energy is

determined by the temperature and surface condition of an object. Human eyes cannot detect

differences in infrared energy because they are primarily sensitive to visible light energy from

400 to 700 nm. Our eyes are not sensitive to the infrared energy.

2.         Stephan Boltzmann Law

The total energy emitted at all wavelengths by a black body is related to the absolute temperature

as

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3.         Wein’s Displacement Law

Wein’s Law tells that objects of different temperature emit spectra that peak at different

wavelengths. It provides the wavelength for maximum spectral radiant emittance for a given

temperature.

The relationship between the true temperature of the black body and its peak spectral exitance or

dominant wavelength is described by this law

The world is not full of black bodies; rather it

comprises of selectively radiating bodies like rocks, water, etc. and the relationship between the

two is given by emissivity (E).

Emissivity depends on object

color, surface roughness, moisture content, degree of compaction, field of view, viewing angle &

wavelength.

An infrared sensor is an electronic device that emits and/or detects infrared radiation in order to

sense some aspect of its surroundings. Infrared sensors can measure the heat of an object, as well

as detect motion. Many of these types of sensors only measure infrared radiation, rather than

emitting it, and thus are known as passive infrared (PIR) sensors.

All objects emit some form of thermal radiation, usually in the infrared spectrum. This radiation

is invisible to our eyes, but can be detected by an infrared sensor that accepts and interprets it. In

a typical infrared sensor like a motion detector, radiation enters the front and reaches the sensor

itself at the center of the device. This part may be composed of more than one individual sensor,

each of them being made from pyroelectric materials, whether natural or artificial. These are

materials that generate an electrical voltage when heated or cooled.

These pyroelectric materials are integrated into a small circuit board. They are wired in such a

way so that when the sensor detects an increase in the heat of a small part of its field of view, it

will trigger the motion detector's alarm. It is very common for an infrared sensor to be integrated

into motion detectors like those used as part of a residential or commercial security system.

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Most motion detectors are fitted with a special type of lens, called a Fresnel lens, on the sensor

face. A set of these lenses on a motion detector can focus light from many directions, giving the

sensor a view of the whole area. Instead of Fresnel lenses, some motion detectors are fitted with

small parabolic mirrors which serve the same purpose.

An infrared sensor can be thought of as a camera that briefly remembers how an area's infrared

radiation appears. A sudden change in one area of the field of view, especially one that moves,

will change the way electricity goes from the pyroelectric materials through the rest of the

circuit. This will trigger the motion detector to activate an alarm. If the whole field of view

changes temperature, this will not trigger the device. This makes it so that sudden flashes of light

and natural changes in temperature do not activate the sensor and cause false alarms.

Infrared motion detectors used in residential security systems are also desensitized somewhat,

with the goal of preventing false alarms. Typically, a motion detector like these will not register

movement by any object weighing less than 40 pounds (18 kg). With this modification,

household pets will be able to move freely around the house without their owners needing to

worry about a false alarm. For households with large pets, sensors with an 80-pound (36 kg)

allowance are also made.

BRAKES:

A brake is a mechanical device which inhibits motion. The rest of this article is dedicated to

various types of vehicular brakes.

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Most commonly brakes use friction to convert kinetic energy into heat, though other methods of

energy conversion may be employed. For example regenerative braking converts much of the

energy to electrical energy, which may be stored for later use. Other methods convert kinetic

energy into potential energy in such stored forms as pressurized air or pressurized oil. Eddy

current brakes use magnetic fields to convert kinetic energy into electric current in the brake

disc, fin, or rail, which is converted into heat. Still other braking methods even transform kinetic

energy into different forms, for example by transferring the energy to a rotating flywheel.

Brakes are generally applied to rotating axles or wheels, but may also take other forms such as

the surface of a moving fluid (flaps deployed into water or air). Some vehicles use a combination

of braking mechanisms, such as drag racing cars with both wheel brakes and a parachute, or

airplanes with both wheel brakes and drag flaps raised into the air during landing.

Since kinetic energy increases quadratically with velocity ( ), an object moving at

10 m/s has 100 times as much energy as one of the same mass moving at 1 m/s, and

consequently the theoretical braking distance, when braking at the traction limit, is 100 times as

long. In practice, fast vehicles usually have significant air drag, and energy lost to air drag rises

quickly with speed.

Almost all wheeled vehicles have a brake of some sort. Even baggage carts and shopping carts

may have them for use on a moving ramp. Most fixed-wing aircraft are fitted with wheel brakes

on the undercarriage. Some aircraft also feature air brakes designed to reduce their speed in

flight. Notable examples include gliders and some World War II-era aircraft, primarily some

fighter aircraft and many dive bombers of the era. These allow the aircraft to maintain a safe

speed in a steep descent. The Saab B 17 dive bomber used the deployed undercarriage as an air

brake.

Friction brakes on automobiles store braking heat in the drum brake or disc brake while braking

then conduct it to the air gradually. When traveling downhill some vehicles can use their engines

to brake.

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When the brake pedal of a modern vehicle with hydraulic brakes is pushed, ultimately a piston

pushes the brake pad against the brake disc which slows the wheel down. On the brake drum it is

similar as the cylinder pushes the brake shoes against the drum which also slows the wheel

down.

Types:

Brakes may be broadly described as using friction, pumping, or electromagnetics. One brake

may use several principles: for example, a pump may pass fluid through an orifice to create

friction:

Frictional brakes are most common and can be divided broadly into "shoe" or "pad"

brakes, using an explicit wear surface, and hydrodynamic brakes, such as parachutes,

which use friction in a working fluid and do not explicitly wear. Typically the term

"friction brake" is used to mean pad/shoe brakes and excludes hydrodynamic brakes,

even though hydrodynamic brakes use friction.Friction (pad/shoe) brakes are often

rotating devices with a stationary pad and a rotating wear surface. Common

configurations include shoes that contract to rub on the outside of a rotating drum, such

as a band brake; a rotating drum with shoes that expand to rub the inside of a drum,

commonly called a "drum brake", although other drum configurations are possible; and

pads that pinch a rotating disc, commonly called a "disc brake". Other brake

configurations are used, but less often. For example, PCC trolley brakes include a flat

shoe which is clamped to the rail with an electromagnet; the Murphy brake pinches a

rotating drum, and the Ausco Lambert disc brake uses a hollow disc (two parallel discs

with a structural bridge) with shoes that sit between the disc surfaces and expand

laterally.

Pumping brakes are often used where a pump is already part of the machinery. For

example, an internal-combustion piston motor can have the fuel supply stopped, and then

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internal pumping losses of the engine create some braking. Some engines use a valve

override called a Jake brake to greatly increase pumping losses. Pumping brakes can

dump energy as heat, or can be regenerative brakes that recharge a pressure reservoir

called a hydraulic accumulator.

Electromagnetic brakes are likewise often used where an electric motor is already part

of the machinery. For example, many hybrid gasoline/electric vehicles use the electric

motor as a generator to charge electric batteries and also as a regenerative brake. Some

diesel/electric railroad locomotives use the electric motors to generate electricity which is

then sent to a resistor bank and dumped as heat. Some vehicles, such as some transit

buses, do not already have an electric motor but use a secondary "retarder" brake that is

effectively a generator with an internal short-circuit. Related types of such a brake are

eddy current brakes, and electro-mechanical brakes (which actually are magnetically

driven friction brakes, but nowadays are often just called “electromagnetic brakes” as

well).

Characteristics:

Brakes are often described according to several characteristics including:

Peak force – The peak force is the maximum decelerating effect that can be obtained.

The peak force is often greater than the traction limit of the tires, in which case the brake

can cause a wheel skid.

Continuous power dissipation – Brakes typically get hot in use, and fail when the

temperature gets too high. The greatest amount of power (energy per unit time) that can

be dissipated through the brake without failure is the continuous power dissipation.

Continuous power dissipation often depends on e.g., the temperature and speed of

ambient cooling air.

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Fade – As a brake heats, it may become less effective, called brake fade. Some designs

are inherently prone to fade, while other designs are relatively immune. Further, use

considerations, such as cooling, often have a big effect on fade.

Smoothness – A brake that is grabby, pulses, has chatter, or otherwise exerts varying

brake force may lead to skids. For example, railroad wheels have little traction, and

friction brakes without an anti-skid mechanism often lead to skids, which increases

maintenance costs and leads to a "thump thump" feeling for riders inside.

Power – Brakes are often described as "powerful" when a small human application force

leads to a braking force that is higher than typical for other brakes in the same class. This

notion of "powerful" does not relate to continuous power dissipation, and may be

confusing in that a brake may be "powerful" and brake strongly with a gentle brake

application, yet have lower (worse) peak force than a less "powerful" brake.

Pedal feel – Brake pedal feel encompasses subjective perception of brake power output

as a function of pedal travel. Pedal travel is influenced by the fluid displacement of the

brake and other factors.

Drag – Brakes have varied amount of drag in the off-brake condition depending on

design of the system to accommodate total system compliance and deformation that

exists under braking with ability to retract friction material from the rubbing surface in

the off-brake condition.

Durability – Friction brakes have wear surfaces that must be renewed periodically. Wear

surfaces include the brake shoes or pads, and also the brake disc or drum. There may be

tradeoffs, for example a wear surface that generates high peak force may also wear

quickly.

Weight – Brakes are often "added weight" in that they serve no other function. Further,

brakes are often mounted on wheels, and unsprung weight can significantly hurt traction

in some circumstances. "Weight" may mean the brake itself, or may include additional

support structure.

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Noise – Brakes usually create some minor noise when applied, but often create squeal or

grinding noises that are quite loud.

Brake boost:

Most modern vehicles use a vacuum assisted brake system that greatly increases the force

applied to the vehicle's brakes by its operator.[1] This additional force is supplied by the manifold

vacuum generated by air flow being obstructed by the throttle on a running engine. This force is

greatly reduced when the engine is running at fully open throttle, as the difference between

ambient air pressure and manifold (absolute) air pressure is reduced, and therefore available

vacuum is diminished. However, brakes are rarely applied at full throttle; the driver takes the

right foot off the gas pedal and moves it to the brake pedal - unless left-foot braking is used.

Because of low vacuum at high RPM, reports of unintended acceleration are often accompanied

by complaints of failed or weakened brakes, as the high-revving engine, having an open throttle,

is unable to provide enough vacuum to power the brake booster. This problem is exacerbated in

vehicles equipped with automatic transmissions as the vehicle will automatically downshift upon

application of the brakes, thereby increasing the torque delivered to the driven-wheels in contact

with the road surface.

Although ideally a brake would convert all the kinetic energy into heat, in practice a significant

amount may be converted into acoustic energy instead, contributing to noise pollution.

For road vehicles, the noise produced varies significantly with tire construction, road surface,

and the magnitude of the deceleration.[2] Noise can be caused by different things. These are signs

that there may be issues with brakes wearing out over time.

Inefficiency:

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A significant amount of energy is always lost while braking, even with regenerative braking

which is not perfectly efficient. Therefore a good metric of efficient energy use while driving is

to note how much one is braking. If the majority of deceleration is from unavoidable friction

instead of braking, one is squeezing out most of the service from the vehicle. Minimizing brake

use is one of the fuel economy-maximizing behaviors.

While energy is always lost during a brake event, a secondary factor that influences efficiency is

"off-brake drag", or drag that occurs when the brake is not intentionally actuated. After a braking

event, hydraulic pressure drops in the system, allowing the brake caliper pistons to retract.

However, this retraction must accommodate all compliance in the system (under pressure) as

well as thermal distortion of components like the brake disc or the brake system will drag until

the contact with the disc, for example, knocks the pads and pistons back from the rubbing

surface. During this time, there can be significant brake drag. This brake drag can lead to

significant parasitic power loss, thus impact fuel economy and vehicle performance.

We all know that pushing down on the brake pedal slows a car to a stop. But how does this

happen? How does your car transmit the force from your leg to its wheels? How does it multiply

the force so that it is enough to stop something as big as a car?

When you depress your brake pedal, your car transmits the force from your foot to its brakes

through a fluid. Since the actual brakes require a much greater force than you could apply with

your leg, your car must also multiply the force of your foot. It does this in two ways:

Mechanical advantage (leverage)

Hydraulic force multiplication

The brakes transmit the force to the tires using friction, and the tires transmit that force to the

road using friction also. Before we begin our discussion on the components of the brake system,

we'll cover these three principles:

Leverage

Hydraulics

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Friction

CHAIN:

Chain is a series of connected links which are typically made of metal. A chain may

consist of two or more links.

Chains are usually made in one of two styles, according to their intended use:

Those designed for lifting, such as when used with a hoist; for pulling; or for securing,

such as with a bicycle lock, have links that are torus shaped, which make the chain

flexible in two dimensions (The fixed third dimension being a chain's length.)

Those designed for transferring power in machines have links designed to mesh with the

teeth of the sprockets of the machine, and are flexible in only one dimension. They are

known as roller chains, though there are also non-roller chains such as block chain.

Two distinct chains can be connected using a quick link which resembles a carabiner with a

screw close rather than a latch.

Uses for chain:

Uses for chain include:

Bicycle chain , transfers power from the pedals to the drive-wheel of a bicycle thus

propelling it

Chain drive , the main feature that differentiated the safety bicycle

Chain gun , type of machine gun that is driven by an external power source, sometimes

connected by a chain, to actuate the mechanism rather than using recoil

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Chain pumps , type of water pump where an endless chain has positioned on it circular

discs

Chain-linked Lewis , lifting device made from two curved steel legs

Chainsaw , portable mechanical, motorized saw using a cutting chain to saw wood.

Chain steam shipping

Curb chain , used on curb bits when riding a horse

Door chain , a type of security chain on a door that makes it possible to open a door from

the inside while still making it difficult for someone outside to force their way inside

Keychain , a small chain that connects a small item to a keyring

Lead shank (or "Stud chain"), used on horses that are misbehaving

Lavatory chain, the chain attached to the cistern of an old-fashioned W.C. in which the

flushing power is obtained by a gravity feed from above-head height. Although cisterns

no longer work like that, the phrase "pull the chain" is still encountered to mean "flush

the toilet".

O-ring chain , a specialized type of roller chain

Roller chain , the type of chain most commonly used for transmission of mechanical

power on bicycles, motorcycles, and in industrial and agricultural machinery

Snow chains , used to improve traction in snow

Timing chain , used to transfer rotational position from the crankshaft to the valve and

ignition system on an internal combustion engine, typically with a 2:1 speed reduction.

Ball and chain, phrase that can refer to either the actual restraint device that was used to

slow down prisoners, or a derogatory description of a person's significant other

Bicycle lock (or "Bicycle Chain"), lockable chain

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Security chain , chain with square edges to prevent cutting with bolt-cutters.

High-tensile chain (or "Transport chain"), chain with a high tensile strength used for

towing or securing loads.

Leg iron chains (Fetters), an alternative to handcuffs

Chain link fencing , fencing that utilizes vertical wires that are bent in a zig zag fashion

and linked to each other

Chain of office , collar or heavy gold chain worn as insignia of office or a mark of fealty

in medieval Europe and the United Kingdom

Chain weapon , a medieval weapon made of one or more weights attached to a handle

with a chain

Omega chain , a pseudo-chain where the 'links' are mounted on a backing rather than

being interlinked

Pull switch , an electrical switch operated by a chain

Flat chain , form of chain used chiefly in agricultural machinery.

Chain Construction:

Chains have a surprising number of parts. The roller turns freely on the bushing, which is

attached on each end to the inner plate. A pin passes through the bushing, and is attached at each

end to the outer plate. Bicycle chains omit the bushing, instead using the circular ridge formed

around the pin hole of the inner plate.

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Chain Dimensions:

Chain types are identified by number; ie. a number 40 chain. The rightmost digit is 0 for chain of

the standard dimensions; 1 for lightweight chain; and 5 for rollerless bushing chain. The digits to

the left indicate the pitch of the chain in eighths of an inch. For example, a number 40 chain

would have a pitch of four-eighths of an inch, or 1/2", and would be of the standard dimensions

in width, roller diameter, etc.

The roller diameter is "nearest binary fraction" (32nd of an inch) to 5/8ths of the pitch; pin

diameter is half of roller diameter. The width of the chain, for "standard" (0 series) chain, is the

nearest binary fraction to 5/8ths of the pitch; for narrow chains (1 series) width is 41% of the

pitch. Sprocket thickness is approximately 85-90% of the roller width.

Plate thickness is 1/8th of the pitch, except "extra-heavy" chain, which is designated by the suffix

H, and is 1/32" thicker.

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ANSI Standard Chain Dimensions

Chain

No.Pitch

Roller

Diameter

Roller

Width

Sprocket

thickness

Working

Load

25 1/4" 0.130" 1/8" 0.110" 140 lbs

35 3/8" 0.200" 3/16" 0.168" 480 lbs

40 1/2" 5/16" 5/16" 0.284" 810 lbs

41 1/2" 0.306" 1/4" 0.227" 500 lbs

50 5/8" 0.400" 3/8" 0.343" 1400 lbs

60 3/4" 15/32" 1/2" 0.459" 1950 lbs

80 1" 5/8" 5/8" 0.575" 3300 lbs

Bicycle and Motorcycle Chain Dimensions

Chain No. PitchRoller

Diameter

Roller

Width

Sprocket

thickness

Bicycle, with Derailleur 1/2" 5/16" 1/8" 0.110"

Bicycle, without

Derailleur1/2" 5/16" 3/32" 0.084"

420 1/2" 5/16" 1/4" 0.227"

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425 1/2" 5/16" 5/16" 0.284"

428 1/2" 0.335" 5/16" 0.284"

520 5/8" 0.400" 1/4" 0.227"

525 5/8" 0.400" 5/16" 0.284"

530 5/8" 0.400" 3/8" 0.343"

630 3/4" 15/32" 3/8" 0.343"

Selecting a Chain

Two factors determine the selection of a chain; the working load and the rpm of the smaller

sprocket. The working load sets a lower limit on pitch, and the speed sets an upper limit.

Maximum Pitch = (900 ÷ rpm ) 2/3

The smaller the pitch, the less noise, wears, and mechanical losses will be experienced.

SPROCKET:

A sprocket or sprocket-wheel is a profiled wheel with teeth, cogs, or even sprockets[ that mesh

with a chain, track or other perforated or indented material. The name 'sprocket' applies generally

to any wheel upon which are radial projections that engage a chain passing over it. It is

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distinguished from a gear in that sprockets are never meshed together directly, and differs from a

pulley in that sprockets have teeth and pulleys are smooth.

Sprockets are used in bicycles, motorcycles, cars, tracked vehicles, and other machinery either to

transmit rotary motion between two shafts where gears are unsuitable or to impart linear motion

to a track, tape etc. Perhaps the commonest form of sprocket is found in the bicycle, in which the

pedal shaft carries a large sprocket-wheel which drives a chain which in turn drives a small

sprocket on the axle of the rear wheel. Early automobiles were also largely driven by sprocket

and chain mechanism, a practice largely copied from bicycles.

Sprockets are of various designs, a maximum of efficiency being claimed for each by its

originator. Sprockets typically do not have a flange. Some sprockets used with timing belts have

flanges to keep the timing belt centered. Sprockets and chains are also used for power

transmission from one shaft to another where slippage is not admissible, sprocket chains being

used instead of belts or ropes and sprocket-wheels instead of pulleys. They can be run at high

speed and some forms of chain are so constructed as to be noiseless even at high speed.

Transportation

In the case of bicycle chains, it is possible to modify the overall gear ratio of the chain drive by

varying the diameter (and therefore, the tooth count) of the sprockets on each side of the chain.

This is the basis of derailleur gears. A 10-speed bicycle, by providing two different-sized driving

sprockets and five different-sized driven sprockets, allows up to ten different gear ratios. The

resulting lower gear ratios make the bike easier to pedal up hills while the higher gear ratios

make the bike faster to pedal on flat roads. In a similar way, manually changing the sprockets on

a motorcycle can change the characteristics of acceleration and top speed by modifying the final

drive gear ratio.

In the case of vehicles with caterpillar tracks the engine-driven toothed-wheel transmitting

motion to the tracks is known as the drive sprocket and may be positioned at the front or back of

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the vehicle, or in some cases, both. There may also be a third sprocket, elevated, driving the

track.

Film and paper:

Moving picture mechanism from 1914. The sprocket wheels a, b, and c engage and transport the

film. a and b move with uniform velocity and c indexes each frame of the film into place for

projection.

Sprockets are used in the film transport mechanisms of movie projectors and movie cameras. In

this case, the sprocket wheels engage film perforations in the film stock. Sprocket feed was also

used for punched tape and is used for paper feed to some computer printers.

A sprocket is a toothed wheel upon which a chain rides. Contrary to popular opinion, a sprocket

is not a gear.

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Sprockets:

There are four types of sprocket;

Type A: Plain Plate sprockets

Type B: Hub on one side

Type C: Hub on both sides

Type D: Detachable hub

Sprockets should be as large as possible given the application. The larger a sprocket is, the less

the working load for a given amount of transmitted power, allowing the use of a smaller-pitch

chain. However, chain speeds should be kept under 1200 feet per minute.

The dimensions of a sprocket can be calculated as follows, where P is the pitch of the chain, and

N is the number of teeth on the sprocket;

Pitch Diameter = P ÷ sin (180° ÷ N)

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Outside Diameter = P × (0.6 + cot ( 180° ÷ N) )

Sprocket thickness = 0.93 × Roller Width - 0.006"

Proceedure for Laying Out a Sprocket

The first thing you need to know to lay out a sprocket is the dimensions of the chain which is to

run upon it, specifically the pitch, roller diameter, and the roller width of the chain. The second

thing you need to know is the number of teeth in the sprocket, which will depend entirely on

your application. From these numbers, the outside diameter and thickness of the required blank

can be calculated.

You'll also need to know the angle between teeth - this is simply the 360° divided by the number

of teeth.

1. Start by drawing

a three radial lines

from the center of

the blank to the

edge, separated by

an angle equal to

the angle between

teeth.

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2. Draw lines

parallel to these

lines, at a distance

equal to the pitch

of the chain.

3. A roller will be

located at each

intersection of the

parallel lines and

the pitch circle.

Draw a circle equal

to the roller

diameter of the

chain.

4. Draw lines

between the roller

centers.

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5. Draw circles

around the roller

centers, that pass

through the

intersection of the

other roller and the

line between

centers.

6. The tooth profile

is as shown.

The sprocket teeth are usually truncated one chain pitch above the bottom of the seat; this is not

shown here. Note that this shape is not the only one that will work - bicycles in particular use

various tooth shapes for different circumstances.

Application:

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Sprockets should be accurately aligned in a common vertical plane, with their axes parallel.

Chain should be kept clean and well lubricated with a thin, light-bodied oil that will penetrate the

small clearances between pins and bushings.

Center distance should not be less than 1.5 times the diameter of the larger sprocket, nor less

than 30 times the chain pitch, and should not exceed 60 times the chain pitch. Center distance

should be adjustable - one chain pitch is sufficient - and failing this an idler sprocket should be

used to adjust tension. A little slack is desirable, preferably on the bottom side of the drive.

The chain should wrap at least 120° around the drive sprocket, which requires a ratio of no more

than 3.5 to 1; for greater ratios, an idler sprocket may be required to increase wrap angle.

FUTURE STUDY:

The project “regenerative braking system” has been successfully designed and tested. It

has been developed by integrating features of all the hardware components used. Presence of

every module has been reasoned out and placed carefully thus contributing to the best working of

the unit. Secondly, using highly advanced IC’s and sensors and with the help of growing

technology the project has been successfully implemented.

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