e-scooter battery state of charge estimation using arduino mega

E-SCOOTER BATTERY STATE OF CHARGE ESTIMATION USING ARDUINO
MEGA 2560
MOHAMAD HAFFIZI BIN YUSSAINI
UNIVERSITI TEKNOLOGI MALAYSIA
PSZ 19:16 (Pind. 1/13)
UNIVERSITI TEKNOLOGI MALAYSIA
DECLARATION OF THESIS / UNDERGRADUATE PROJECT REPORT AND COPYRIGHT
Author’s full name : MOHAMAD HAFFIZI BIN YUSSAINI
Date of Birth
: 23TH AUGUST 1992
Title
: E-SCOOTER BATTERY STATE OF CHARGE ESTIMATION USING ARDUINO
MEGA 2560
Academic Session : 2014/2015
I declare that this thesis is classified as:
CONFIDENTIAL (Contains confidential information under the Official Secret Act
1972)*

RESTRICTED
(Contains restricted information as specified by the
organization where research was done)*
OPEN ACCESS
I agree that my thesis to be published as online open access
(full text)
I acknowledged that Universiti Teknologi Malaysia reserves the right as follows:
1. The thesis is the property of Universiti Teknologi Malaysia
2. The Library of Universiti Teknologi Malaysia has the right to make copies for the
academic purposes.
Certified by:
SIGNATURE
SIGNATURE OF SUPERVISOR
MOHAMAD HAFFIZI BIN YUSSAINI
DR. MOHD JUNAIDI BIN ABDUL AZIZ
(920823-01-6153)
Date: 29TH JUNE 2015
NOTES:
*
Date: 29TH JUNE 2015
If the thesis is CONFIDENTAL or RESTRICTED, please attach with the letter from
the organization with period and reasons for confidentiality or restriction.
“I hereby declare that I have read this project and in my/our*
opinion this project is sufficient in terms of scope and quality for the
award of the degree of Bachelor of Engineering (Electrical - Electric)
Signature
: ………………………….........
Name of Supervisor : DR. MOHD JUNAIDI BIN ABDUL AZIZ
Date
: 29TH JUNE 2015
E-SCOOTER BATTERY STATE OF CHARGE ESTIMATION USING
ARDUINO MEGA 2560
MOHAMAD HAFFIZI BIN YUSSAINI
A project submitted in partial fulfillment of the
requirements for the award of the degree of
Bachelor of Engineering (Electrical - Electric)
Faculty of Electrical Engineering
Universiti Teknologi Malaysia
JUNE 2015
ii
DECLARATION
“I declare that this project entitled “E-Scooter Battery State Of Charge
Estimation Using Arduino Mega 2560” is the result of my own research
except as cited in the references.”
Signature
: ………………………………………....
Name of Candidate : MOHAMAD HAFFIZI BIN YUSSAINI
Date
: 29TH JUNE 2015
iii
Specially dedicated to Ma, Abah,
siblings and friends for their
love and support.
iv
ACKNOWLEDGMENT
Alhamdulillah – recognition be to Allah, the Merciful, the Benevolent for all
His gift and sympathy. I had the strength to finish my last year project entitled "EScooter Battery State Of Charge Estimation Using Arduino Mega 2560" despite the
fact that I need to experience a few troubles along the way.
Most importantly, I might want to express my appreciation to my supervisor
Dr. Mohd Junaidi bin Abdul Aziz for his profitable remark, exhortation, most
extreme tolerance and commitment for managing me in the consummation of this
project. I admire all his time and assets that he has given in backing of my
exploration and training.
Likewise because of my kindred companions for their co-operation and help.
Not to overlook, my guardians, sister and siblings who upheld me as the year
progressed. A debt of gratitude is in order for their worry, consolation and
comprehension.
At last, because of the individuals who have contributed straightforwardly or
in a roundabout way to the accomplishment of this venture whom I have not
specified their name particularly. Without them, this undertaking would not
successful
v
ABSTRACT
In the current climate debate, vehicles without any emissions are widely
considered to be the future of transportation. This type of vehicle is known as electric
vehicle. The battery system is one of the main parts of the electric vehicle. It is
important to display the battery information to the driver at all times. Therefore, a
user interface that displays the battery information to the driver should be designed
for electric vehicles. In this project, a user interface to display the electric vehicle’s
battery information was designed. Sensors such as optocoupler are used to retrieve
battery signals which are battery voltage. An Arduino microcontroller is used to
process data from the sensor, while a LCD keypad shield which is compatible with
the microcontroller is used to display the battery data from the microcontroller. In
conclusion, an user interface that can display the electric vehicle’s battery
information is successfully designed and ready to be implemented in the real-world.
vi
ABSTRAK
Kini, kenderaan yang tidak mengeluarkan gas seperti karbon dioksida
dianggapsebagai jenis pengangkutan untuk masa depan. Kenderaan sebegini dikenali
sebagai kenderaan elektrik. Dalam sesebuah kereta elektrik, sistem bateri
merupakansalah satu komponen yang penting. Oleh itu, antara muka pengguna yang
memaparkan maklumat bateri kepada pemandu perlu direka untuk digunakan dalam
kenderaan elektrik. Dalam projek ini, sebuah antara muka pengguna untuk
memaparkan maklumat bateri kenderaan elektrik telah direka. Sensor-sensor seperti
optocoupler digunakan untuk mendapatkan isyarat bateri. Optocoupler digunakan
untuk mendapat voltan bateri. Data dari sensor akan diproses oleh mikropengawal
Arduino, manakala perisai LCD yang serasi dengan mikropengawal Arduino
digunakan untuk memaparkan data bateri dari mikropengawal. Secara keseluruhan,
antara muka pengguna yang boleh memaparkan maklumat bateri kenderaan elektrik
telah direka dan bersedia untuk digunakan dalam dunia sebenar.
vii
TABLE OF CONTENTS
CHAPTER
1
2
TITLE
PAGE
DECLARATION
ii
DEDICATION
iii
ACKNOWLEDGMENT
iv
ABSTRACT
v
ABSTRAK
vi
TABLE OF CONTENTS
vii
LIST OF FIGURES
x
LIST OF TABLE
xii
LIST OF ABBREVIATIONS
xiii
LIST OF SYMBOLS
xiv
LIST OF APPENDICES
xv
INTRODUCTION
1
1.1
Background of Study
1
1.2
Problem Statements
2
1.3
Objectives of Research
2
1.4
Research Scopes
3
1.5
Outlines of Project
4
LITERATURE REVIEW
5
viii
2.1
Introduction
5
2.2
Parameters Battery
6
2.2.1 Cell and Battery Voltage
7
Battery Voltage Measuring Method
9
2.3.1 Isolation Amplifier
9
2.3.2 Optocoupler
10
2.3.3 DC-DC Converter
11
SOC Estimation
12
2.4.1 Open Circuit Voltage Method
13
2.4.2 Coulomb Counting Method
14
Arduino
14
2.3
2.4
2.5
3
4
5
RESEARCH METHODOLOGY
16
3.1
Introduction
16
3.2
Atomistix Tool Kit Software
17
RESULTS AND DISCUSSION
25
4.1
Introduction
25
4.2
Sensor Circuit Test Result
26
4.3
Project Outcome
28
CONCLUSION AND FUTURE
31
RECOMMENDATIONS
6
5.1
Conclusion
31
5.2
Future Recommendations
32
PROJECT MANAGEMENT
34
6.1
Introduction
34
6.2
Project Schedule
35
ix
REFERENCES
36
APPENDIX
42
x
LIST OF FIGURES
NO.
TITLE
PAGE
1.1
Project flow for FYP 1
4
2.1
Battery cell immerse into electrolyte
6
2.2
Charging process for Lead Acid battery
7
2.3
Block diagram of the ISO120 isolation amplifier
8
2.4
Block diagram of the optocoupler circuit
11
2.5
Block diagram of the DC-DC converter circuit
12
3.1
Simple understanding on the project methodology
17
3.2
Sensor circuit schematic diagram
19
3.3
Top view of pin configuration and the schematic
19
3.4
Arduino Mega ADK microcontroller development board
21
3.5
LCD keypad shield
22
3.6
Arduino Mega 2560 with LCD keypad shield
22
3.7
Arduino programming flowchart
23
3.8
3D Viewer window
24
3.9
Arduino programming code
25
4.1
Graph of optocoupler output voltage versus input voltage
26
4.2
User interface
28
4.3
Measurement of total battery voltage
29
4.4
Voltage vs SOC result
30
xi
LIST OF TABLES
NO.
TITLE
PAGE
2.1
Classification of SOC estimating
13
4.1
Optocoupler 1 experiment results
26
6.1
Project Gantt chart for Semester One
36
6.2
Project Gantt chart for Semester Two
36
xii
LIST OF ABBREVIATIONS
ATV
-
All-Terrain Veficle
ATeV
-
All-Terrain elecric Vehicle
EV
-
Electric Vehicle
HEV
-
Hybrid Electric Vehicle
SOC
-
State Of Charge
DC
-
Direct Current
Li-Ion
-
Lithium Ion
OCV
-
Open Circuit Voltage
FYP
-
Final Year Project
xiii
LIST OF SYMBOLS
V
-
Voltage
Ah
-
Amphour
Ω
-
Ohm
E
-
Internal voltage
I
-
Current
R
-
Resistance
Wh/kg
-
Watt per kilogram
P
-
Power
η
-
Efficiency
0C
-
Degree of Celcius
%
-
Percentage
CN
-
Battery capacity
Vout
-
Output voltage
Vref
-
Reference voltage
SOCo
-
Intial state of charge
Mm
-
Millimeter
A
-
Ampere
Min
-
Minute
xiv
LIST OF APPENDICES
NO.
A
TITLE
TOSHIBA TLP550 datashee
PAGE
76
1
CHAPTER 1
INTRODUCTION
1.1
Background of Study
Drastic changes in the world’s weather have become a popular discussion topic among the
general public. In December 2009, environment ministers from 190 different countries
attended the Copenhagen climate change conference to figure out methods of slowing down
global warming [1]. They agreed that anthropogenic greenhouse gases, especially carbon
dioxide is one the main causes of the drastic climate changes. From the works of Herzog
(2009), it is proven that road transportation is one of the main contributors to the world’s
carbon dioxide emissions [2]. Therefore, global warming can be slowed down by reducing
emissions from vehicles.
Due to public concern on climate changes, automobile industries are developing
vehicles without any gas emissions. To produce cars without any gas emissions, the
combustion engine of the car has to be replaced by electric drives.This type of vehicle is
known as electric vehicle. Electric vehicles are driven by electric motor powered by
electrical energy from batteries of the car, thus making them environmental friendly.
According to Keoun (1995), to convert a conventional car to
2
an electric car the parts that have to be removed are the engine, starter, alternator, fuel tank
and exhaust pipe. On the other hand, parts such as batteries and electric drive train have to
be installed [3].
1.2
Problem Statement
The battery management system is one of the main components of the electric vehicle is
the battery system. The battery system provides electric supply to power up the EScooter. Without the battery system, the E-Scooter would not move. Since it is
important, the studies include the parameters of battery, information such as battery
voltage, battery current and State of Charge (SOC) of the battery must be displayed for
the view of user. With the vast improvement in technology, it is possible to design a user
interface to display the electric vehicle’s battery information on an LCD.
1.3
Objectives of Research
The main objectives of this project is to estimate the SOC of E-Scooter battery and
display the E-Scooter battery information on LCD display for user interface. Sensor
circuits developed to transfer signal from the E- Scooter's battery to Arduino. Then,
investigate the feasibility of LCD Keypad Shield to display output signal.
3
1.4
Research Scopes
Several scopes had been fixed in order to achieve the objectives of the project.
The scopes of this project can be divided into three parts. The scopes of the study are as
follows:
1)
The battery parameters
2)
Battery testing using a 12V Deep Cycle Lead Acid battery with nominal capacity
of 7.0Ah each.
3)
Sensor circuits that have to be designed are the sensors to obtain battery voltage.
4)
Information to be displayed on the user interface are: battery voltage and State of
Charge (SOC) as date and time.
1.5
Outlines of Project
This project consists of five chapters. The background of study, problem
statement, objective, scope and outline of the project of this project will be discussed in
Chapter 1. Literature reviews on related works and theories of the project including Lead
acid cell discharge characteristics and Battery Voltage Measuring Method are done in
chapter 2. The methodology on the hardware and software implementation to achieve
the objective of this project is described in chapter 3. The results and discussions on the
design and performance of the user interface will be presented in chapter 4. Lastly in
chapter 5, a conclusion will be given along with suggestions for future works and to
improve this work.
4
1.6 Summary of Work
The flowchart in figure 1.2 illustrates the tasks that need to be accomplished
accordingly to complete the project.
Figure 1.1
Project flow for FYP1
5
CHAPTER 2
LITERATURE REVIEW
2.1
Introduction
Battery is a device that converts electrical energy. The most popular batteries for
electrical energy storage due to ability to provide fast response to energy demand is
rechargeable battery. For EV battery system, The battery system of EV consists of small
groups of cells connected in series, termed as modules. Several battery modules are then
connected in series to form the battery system[4] , which the cells have positive and
negative electrodes joined by an electrolyte. Figure 2.1 shows the battery cell that
immersed into an electrolyte. There are lot of kinds of battery which have different
parameters because have different chemical compound in the battery.
6
Figure 2.1
Battery cell immerse into electrolyte [18]
2.2 Parameters of Battery
A basic understanding of the battery chemistry is very important. Batteries can
be divided into different categories. Different types of battery have different battery
chemistry. Batteries that are used in EV are the rechargeable secondary cell type. Figure
2.2 shows the type of Lead Acid battery reaction in charging process. At the negative
plate, the battery has spongy Lead as the active material, while Lead Oxide is as the
active material on positive plate. These both plates are immersed in an electrolyte of
Sulphuric Acid.
7
Figure 2.2
Charging process for Lead Acid battery [19]
The battery can be treated as a ‘black box’ which has a range of performance
criteria. The criteria include cell and battery voltages, specific energy, specific power,
energy efficiency and operating temperature. The next subtopic will discuss deeply on
the criteria.
2.2.1 Lead Acid
Early 1990, Lead Acid battery has been used in electric cars [9]. It consists of a
lead-dioxide cathode, sponge metallic anode and sulphuric acid as the electrolyte. Lead
Acid battery is the most common battery sales which is about 40-45% of the global
battery sales. Furthermore, it’s also variety of sizes and designs and available in large
quantities. They are manufactured in smaller capacity from 1Ah up to several thousand
Ah. The discharge curve of the lead-acid battery is shown in figure 2.5. The discharge
8
curve is steeper cell’s discharge curve, meaning more accurate voltage measurement and
SOC calculation. The special characteristic for lead acid battery is decomposing very
slowly as the lead and Lead Oxide is not stable in Sulphuric Acid [9]. This battery will
go to a process of sulphating when the battery is left in a discharge state for a long
period. like other bateries the capacity and efficiency of the lead acid battery will be
reduced at low temperature (Prinsloo, 2011) [6].Figure 2.8 shows a curve of discharge of
Deep Cycle Lead Acid battery by brand of Matrix battery.
Figure 2.3
Lead acid battery
9
2.3:
Battery Voltage Measuring Method
In this report, three voltage measuring methods will be discussed: (i) Isolation
amplifier, (ii) Optocoupler and (iii) DC-DC converter.
2.3.1
Isolation Amplifier
Through galvanic isolation, isolation amplifiers can be obtained by separate the
input from its output. The voltage information is transferred from the input to the output
through three different methods: transformer, capacitive and optical coupling.
To
transfer voltage through the isolation barrier, the voltage signal have to be changed
either a pulse width modulated or voltage dependent frequency signal. Based on the
works of Meyrath (2005), voltage controlled oscillator (VCO) is used generate the PWM
signal through the voltage dependant frequency signal and a modulation process [13].
The advantages of using isolation amplifier are high accuracy and low current
consumption, while the disadvantages are high costs and difficulty in connection makes
isolation amplifier a non-feasible option. Block diagram of an isolation amplifier is
shown in figure 2.6 (Burr Brown) [14].
10
Figure 2.3
2.3.2
Block diagram of the ISO120 isolation amplifier [15]
Optocoupler
Optocoupler do not convert the input voltage signal to determined switching
waveform like isolation amplifiers. the input voltage signal generates a constant current
through the optocoupler’s LED which consists of a light emitting diode (LED) and light
to be radiated to receiving phototransistor. At the output part, the received current will
be converted back to a voltage signal and sent to a microcontroller circuit where the
voltage signal will be measured [6]. The advantage using optocoupler method of
measuring the battery voltage is the most economical method. However, it has lower
measurement accuracy compared to the other measurement methods.
11
Figure 2.4
Block diagram of the optocoupler circuit [6]
2.3.3 DC-DC Converter
The battery voltage can be measure by using DC-DC converter method and the
block diagram of a DC-DC converter circuit for voltage measurement is shown in figure
2.8 [15]. A full bridge circuit with transformer isolation is implemented. A planar
transformer is used to provide higher efficiency and low leakage inductance. The input
voltage can be sent directly from the primary side of the transformer to the secondary
side with a 1:1 transformer and PWM controllers with 50% duty cycle. The advantage
by using this method is voltage measurement accuracy is high. However, the
components used have high power ratings and therefore will have high current
consumption plus the circuit is complex to be integrated in an EV [6].
12
Figure 2.5
2.4
Block diagram of the DC-DC converter circuit [15]
SOC Estimation
The SOC of battery is an important parameter for controlling strategy and used to
describe its remaining capacity [16]. The SOC estimation will affect the life of
expectancy battery, which protect battery and prevent over discharge. The SOC can be
defined as;
SOC(%)  SOC 0  
1
dt
CN
(2.1)
13
Where SOC(%) shows the capacity remain in the battery while SOC0 is the
value from curve of open circuit voltage (OCV) versus SOC. I is the current output from
battery and C N constant depends on the battery capacity. Table 2.4 presents the
classification of SOC estimating mathematical methods
Table 2.1 Classification of SOC estimating [17]
2.4.1
Open-Circuit Voltage Method
The various values of open circuit voltage (OCV) of the Depth-of-Charge can be
obtained by direct measured in a separate experiment. The OCV method is in category
of direct measurement because it refers to some physical battery properties. In this
experiment, the battery is charged with a constant current to a specific Depth-of-Charge,
14
the current is then interrupted and the battery is allowed to rest for a certain period of
time. OCV of batteries is proportional to the SOC for a long period. All batteries are
different OCV and SOC relationship.
2.4.2
Coulomb Counting Method
This method, monitoring and memorizing the currents flowing into and out from
a battery for long time. It was impractical SOC estimation but critical in verifying the
accurancy of estimated results from other methods. Equation 2.1 is calculated of SOC by
this method;
soc(t )  soc(t  1) 
I (t )
t
Qn
(2.2)
The factors of battery history, cycle life, temperature and discharge current will affect
the accuracy of coulomb counting method. Therefore, by using this method, user needs
some precaution.
2.5 Arduino
Arduino is a microcontroller board that can be modified to perform a desired fuction
such as it can be modified to process information got from the input ports before sending
it to a joined output ports. It is regularly utilized as a part of an installed framework
15
where it goes about as a center man to get process and exchange information from a
source to a output ports. By and large, the Arduino board comprises of a processor,
power supply, input/output ports, USB port and some connectors. The microcontroller
chip utilized on an Arduino board is an Atmel based Microcontroller. A voltage
controller is accessible on the Arduino board. The capacity of this voltage controller is to
change over outside source voltage from the scope of 10.5V-12.7V to a controlled 5V
DC voltage. This 5V will be utilized as the power source of the Arduino circuit board
[23].
The quantity of I/O ports accessible in an Arduino board varies for every model.
In the Arduino load up, there is a gem oscillator that creates a clock beat for the
procedure of the chip. The rate of the microcontroller in executing a guideline is taking
into account the recurrence of the clock beat. The USB port gives a method for
correspondence between the Arduino board with the PC for programming purposes. In
addition, the USB port offers another method for fueling on the Arduino board as the 5V
voltage needed to power up the Arduino can be supplied to the Arduino board
specifically from the PC.
16
CHAPTER 3
RESEARCH METHODOLOGY
3.1
Introduction
This chapter will start by discussing the overall concept or methodology that will
be used in this project. Next, is the discussion about the sensor for voltage. Besides, the
estimation SOC will be detailed on how it can be calculated. This methodology chapter
is to detail about the project work on the calculation, about the experiment and
something that needs to design if necessary such as PCB board for the sensor circuit.
Furthermore, the Arduino programming and Android programming flowcharts are
explained.
17
3.2
Project Concept
Firstly, the concept of electric vehicle is shall to understand clearly. All basic
concept of electric vehicle that related to the development of EV was collected from
reference books, previous research and so on that have relation to the project. The
parameters of battery such as SOC and battery voltage are determined. . Battery
parameters from the electric vehicle are transferred to the microcontroller through sensor
circuits. Besides, Sensor circuits used to obtain the battery parameters are not identical.
Optocoupler circuit is used to obtain the voltage of battery cell
Figure 3.1
Project methodology
18
3.3
Sensor Circuit Components and Design
The designed sensor circuit to obtain battery voltage values is shown in figure
3.2. In the figure, optocoupler circuit connection is on the left of the figure
TLP 550 optocoupler manufactuered by Toshiba is used to measure battery
voltage. Figure 3.2 shows a pin configuration (top view) and the schematic of TLP 550,
It consists of a light emitting diode and a photodiode transistor. According to the
TLP550 datasheet, this optocoupler has no base connection and therefore is suitable to
be implemented at noisy environmental condition[24]. The 5kΩ resistor at the input part
of the optocoupler circuit and the 330Ω resistor at the output part of the optocoupler
circuit are used to limit the current flowing through the light emitting diode. The
maximum output voltage of the optocoupler circuit is equal to the applied Vcc voltage
(5V in this project). Experiment is conducted by varying input voltage starting at 10.0V
up to 20.0V with 0.5 increments using a DC power supply. From the result obtained, the
equation to convert the output voltage value from the optocoupler circuit back to the
battery cell voltage can be found. The equation is obtained from the curve optocoupler
output voltage versus input voltage. Results of the simulation will be shown in the next
chapter
19
Figure 3.2
Figure 3.3
Sensor circuit schematic diagram
Top view of pin configuration (left) and the schematic (right) [24]
20
3.4
Estimation of SOC
The equation of SOC is stated at (2.6). Firstly, the graph of OCV versus SOC is
determined by finding the middle of charging and discharging graph. After that, from the
sensor circuit, the voltage of battery is defined which can determine the SOC0. The
equation (2.6) also needs current and it obtained from the current transducer. The
equation (2.6) needs to code in programming, so that the capacity remains in the battery
will be displayed for user.
3.5
Arduino Hardware and Programming
The Arduino Mega 2560, shown in figure 3.4 is chosen as the microcontroller
development board in this project mainly due to its compatibility with Arduino
embedded LCD. Besides, the availability of open source codes, large number of
libraries, cheap price and conveniences in boot loading are also reasons why the Arduino
Mega 2560 is chosen
The Arduino Mega 2560 can accept input voltage from 6V to 20V, however, the
recommended input voltage range is from 7V to 12V. Users must be reminded that if the
external supply source supplied to the Arduino Mega 2560 is higher than 12V the board
may suffer from overheating problems. There are pins on the board that can provide
output voltage of 5V and 3.3V.Similar to the Arduino Mega ADK, the Arduino Mega
2560 uses an 8-bit Atmega2560 chip as the processor. RISC architecture is implemented
in this processor to provide faster execution of programming instructions [27].
21
The processor provides 256 kilobytes of flash memory, 8 kilobytes of internal SRAM
and 4 kilobytes of EEPROM. The clock pulse of the microcontroller board is supplied
by a 16MHz crystal oscillator. This microcontroller development board provides 54
digital I/O pins where 15 of them can provide PWM output. A total of 16 analog input
pins are provided, where these pins can function as ADC pins [27].
Figure 3.4
Arduino Mega ADK microcontroller development board
This microcontroller board will be shield with a Arduino LCD keypad shield
which are both accessible from Cytron Technologies. The PORT is chosen when an
Arduino coding is to be transferred to the microcontroller, while the RUN mode is
chosen when the user needs the Arduino board to run the code. The Arduino coding will
fail to be transferred to the microcontroller if the mode is situated to RUN
22
Figure 3.5
Figure 3.6
LCD keypad shield
Arduino Mega 2560 with LCD keypad shield
23
Figure 3.7
Figure 3.8
Arduino programming flowchart
Arduino programming code
24
The most important part of the Arduino code is the chose the correct pin of LCD
keypad shield. If fail to select the correct pins used on LCD panel the data signal will not
displayed. based on the coding look at what it says in the description: "Pins 8, 9, 4, 5, 6
and 7 are used to interface with the LCD".
25
CHAPTER 4
RESULTS AND DISCUSSION
4.1
Introduction
This chapter examines the results of calibration test consequences of optocoupler
circuit, shows the optocoupler test result and display SOC of the battery cell.
Furthermore, the full mix of the entire undertaking and screenshots of the task are
indicated.
26
4.2
Sensor Circuit Test Results
Input Voltage(V)
Optocoupler Output Voltage(V)
6
6.5
7
7.5
8
8.5
9
9.5
10
10.5
11
11.5
12
12.5
4.95
4.88
4.8
4.72
4.64
4.55
4.47
4.38
4.31
4.22
4.13
4.05
3.97
3.88
Table 4.1
Optocoupler 1 experiment results
6
5
4
3
Series1
2
1
0
0
Figure 4.1
5
10
15
Graph of optocoupler output voltage versus input voltage
27
Table 4.1 shows the observation the output voltage obtained from optocoupler
test result by varies input from 12.5V to 6.0V with increment 0.5V from first value to
next value in order to obtain equation and convert the output value to find battery
voltage using DC power supply. Then, the linear graph will be obtained by plot the
graph based on the data result with the gardient -0.1673. From the results, it can be seen
taht relationship between input voltage and the output voltage is inversely proportional.
By using basic mathematic the equation of the graph is obtained as;
y = -0.1673x + 5.9112
(4.1)
By letting x as the subject in order to find battery voltage, we find that new
equation (4.2) where x represent battery voltage and y represent optocoupler output
voltage.
x = (5.9112 - y) / 0.1673
(4.20
The result that we obtained from the equation (4.2) which is programmed into
the microcontroller Arduino Mega 2560 to find battery voltage sing data received from
sensor circuit is not exactly same as the actual result because the connection from
battery to the optocoupler input pin or too much vibration to optocoupler may affect the
test results. Other than that, no ideal electronic components in the world. Means
different optocoupler circuit will be obtained different output results. Therefore, more
than 5 test is needed to get very accurate equation to programmed into the
microcontroller Arduino Mega 2560.
28
4.3 Project outcome
A few outcomes were taken during this present reality execution of the project
to watch the precision of the battery qualities being measured. Figure 4.2 shows how the
user interface looks like when the application is running, while figure 4.4 demonstrates
the estimation of the total battery voltage measured using a multimeter. It can be seen
from figure 2 assumes that the estimation of total battery voltage are not
indistinguishable. The equation (2.6) is utilized to discover the percent of limit stay in
each of battery. The OCV is alluding to the estimation of voltage while the SOC0 relies
on upon the voltage esteem as demonstrated in Figure 4.6. After all the estimation of
parameter in the equation (2.6) is acquired, the SOC(%) can be ascertained, and show it
for user.
Figure 4.2
User interface
29
Figure 4.3
Measurement of total battery voltage
In figure 4.3, the estimation of total battery voltage
demonstrated using
multimeter is 12.81V, the deliberate total battery voltage quality using sensor circuit is
12.78V. The quality measurement not quite same as the showed in the user interface..
This error is because of the mistake of the optocoupler circuit. Despite the fact that
adjustment is done, the qualities measured will at present have an exactness of ±0.05.
The present meter in the interface is demonstrating an estimation of 0A as there is no
burden joined with the battery. As said over, this distinction in worth is because of the
error of the optocoupler circuit.
30
Figure 4.4
Voltage vs SOC result
As we can be seen from the figure 4.4, diverse voltage qualities will cause the
SOC to appear as something else. For battery voltage higher than 12.70V, a SOC with
100% is demonstrated. A SOC with 90% is indicated for battery voltage in the scope of
12.50V - 12.62V, while SOC with 30% is demonstrated for battery voltage in the scope
of 11.75V – 11.89V. On the off chance that the battery if inside of the scope of 11.31V11.57V, a battery with 10% will be demonstrated, though a battery with 0% will be
demonstrated for battery values under 10.50V.
Figure 4.4 also shows the SOC are displayed by the LCD when Arduino Mega
2560 receive specificsignal from the sensor. This result is obtained based on calculation
using value from sensor circuit. The calculated value will displayed in range 1 to 100% ,
means when the battery cell already full charged the LCD will shows 100% capacity of
SOC.
31
CHAPTER 5
CONCLUSION AND FUTURE RECOMMENDATIONS
5.1
Conclusion
Project management include project planning, organizing and controlling
resource within specified time period. The objective of project management is to achieve
the project’s goal. This project had displayed the configuration of a user interface that
can be utilized as a part of auto businesses to show the electric vehicle's battery
parameters. The principle target of the project has been accomplished effectively. The
user interface has displayed capacity total battery voltage, battery current, state of charge
(SOC) as needed in the extent of this task.
The second target of this project which is to create sensor circuits to transfer
information from the E-Scooter battery to the microcontroller was too accomplished.
Optocoupler circuits were planned and executed to get the battery parameters and
exchange it to the Arduino microcontroller. Alignment tests were done on the sensors to
enhance the exactness of the sensors.
32
As a conclusion, all the goals of this task are effectively accomplished and the
user interface can be relied upon to be executed in electric vehicle to monitor the battery
parameter of the vehicle.
5.2
Future Recommendations
Utilizing the best sensor as a part of request to quantify an exactness of battery
voltage. Moreover, a littler sensor circuit will decrease the general space and weight.In
this project, a blend between mechanical understudy and electrical understudy are
important to finish the undertaking. The piece of adjust for the E-Scooter should be
possible by them. Everything segment need to be prepared before which can
straightforwardness to deal with that.
33
CHAPTER 6
PROJECT MANAGEMENT
6.1
Introduction
Project administration is critical to accomplish all project objectives, for this
situation, the goals of the study. project administration is separated into task arranging,
sorting out and controlling the assets inside of a period interim. In this study, there are a
few requirements and confinements that should be overcome by the specialist, which are
examination extensions, exploration time, exploration spending plan and human asset to
perform the exploration action.
34
6.2
Project Schedule
Gantt graphs for Semester One and Two are demonstrated in Table 6.1 and 6.2
separately. From the Gantt outline in Table 6.1, there is some deferral in the project
foundation study. This is because of the late task of administrator to the understudies.
Other than that, the 4th year issue based lab began sooner than the date of the declaration
of director in control for the last year venture. Subsequent to talking about with the boss
on the title that should be done, then just the study on the past works were finished.
Other than that, different projects initiated as proposed on date. The red cells speak to
the normal length of time of every assignment, while the green cells speak to the real
term of every errand.
Then, Table 6.2 demonstrates the project Gantt graph for Semester Two. As
opposed to Semester One, there was a sudden long postpone in some assignment
because of the long recreation time. Nonetheless, the scientist began to compose the
diary sooner than the booked so as to start to the due date of meeting paper
accommodation to IEEE gathering in Kuala Lumpur. In any case, toward the end of the
venture, the analyst has the capacity present the proposition as planned.
35
Week
Task
1 2 3 4 5 6 7 8 9
1
1
1
1
1
1
0
1
2
3
4
5
FYP briefing and supervisor
assigning
Choose the project title
Analysis on chocen topic
Research on related work
Literature review
Preparing project proposal
Circuit design
Components purchasing
Presentation of FYP 1
Preparing for FYP 1 report
Table 6.1: Project Gantt chart for Semester One
Week
Task
1 2 3 4 5 6 7 8 9
Development
1
1
1
1
1
1
1
1
1
1
2
0
1
2
3
4
5
6
7
8
9
0
of
software
Collecting
Data
and Result
Make An Analysis
And Result
Final
Seminar
Presentation 2
Final
Project
Draft
Project
Submission
Table 6.2: Project Gantt chart for Semester Two
36
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40
APPENDIX A