solar panel circuit design
DESCRIPTION
Internship ReportTRANSCRIPT
VIETNAM NATIONAL UNIVERSITY – HANOI
UNIVERSITY OF ENGINEERING AND TECHNOLOGY
FACULTY OF ELECTRONICS AND TELECOMMUNICATIONS
FINAL REPORT
COURSE: PROJECTS AND SYSTEMS ENGINEERING
Student: Ngo Khac Hoang
Student ID: 10020141
Class: K55Đ
Lecturer: Assoc. Prof. Dr. Nguyen Quoc Tuan
Advisor: Assoc. Prof. Dr. Nguyen Linh Trung
Hanoi, February 2014
THE COMMENT OF ADVISOR
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ESTIMATION:
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REPORTER ADVISOR
SOLAR PANEL CHARGE CONTROLLER
Submitted by Ngo Khac Hoang
Intern from University of Engineering and Technology
Vietnam National University, Hanoi
Supervisor: Dr. Aaron James Danner
In partial fulfillment of the requirements of the Undergraduate Research Attachment Programme
Department of Electrical and Computer Engineering
Faculty of Engineering, National University of Singapore.
Solar Panel Charge Controller 2012
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ACKNOWLEDGEMENT
I would like to express my sincere gratitude to my supervisor, Dr. Aaron James
Danner for his guiding, suggestions and encouragements. He spent time to help me to
understand and complete my works step by step throughout my internship period.
I would also like to thank PhD Student Mr. Mridul Sakhuja for his assistance and
helping me to access Digital Electronics Laboratory to do my measurement with solar panels.
He also helped me to complete my final presentation and report. Acknowledgement is also
given to other interns working in Spin and Energy Laboratory, especially Jordan Kodner,
Rumit Kumar Singh and Pooja Sehgal. They supported me in my research work.
I want furthermore to thank all the staff members in Spin and Energy Laboratory and
Digital Electronics Laboratory for give me good conditions to work and take the experiments.
Last but not least, I acknowledge Department of Electrical and Computer Engineering
for providing me the opportunity to do my research under convenient conditions with
enthusiastic persons and get valuable experiences.
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ABSTRACT
The aim of this project is to build a charging circuit with 24 small-sized solar panels
which is then controlled by a low power microcontroller. This power charging circuit is used
to supply an indoor solar robot which needs a stable voltage from 1.8 to 3.6 volts.
There are required conditions for the power charging system: (1) supplying a target
voltage and (2) tracking the in maximum power point. That is the reason why the charge
controller is necessary.
This project solves those conditions. The solution for first conditions is making many
different combinations of solar panels in charging circuit. Therefore, we can choose the
suitable combination to get required voltage. The microcontroller changes the combination by
flipping the switches between solar panels. Furthermore, the useful combination must be
symmetrical so that each solar panels and whole system work at maximum power point.
This report show how the power charging circuit can be connected in symmetrical
way. 24 panels were divided into 6 blocks with 4 solar panels inside each. By making
symmetrical combinations of 4 panels in each block and symmetrical combinations between 6
blocks, we can make useful combinations of whole charging circuit.
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TABLE OF CONTENTS
ACKNOWLEDGEMENT...................................................................................................................2
ABSTRACT ..........................................................................................................................................3
LIST OF FIGURES..............................................................................................................................6
LIST OF TABLES ...............................................................................................................................6
LIST OF APPENDICES......................................................................................................................6
LIST OF SYMBOLS AND ABBREVIATIONS .............................................................................6
INTRODUCTION ................................................................................................................................7
1. Background ................................................................................................................................7
2. Object ..........................................................................................................................................7
I. SOLAR PANEL AND CHARGE CONTROLLER .................................................................8
1. Solar panel ..................................................................................................................................8
a. Background.............................................................................................................................8
b. Characteristics .......................................................................................................................9
2. Charge controller .................................................................................................................... 11
a. Motivation ............................................................................................................................ 11
b. Solution ................................................................................................................................ 12
II. POWER CHARGING CIRCUIT ......................................................................................... 13
1. Purpose..................................................................................................................................... 13
2. Initial principle ........................................................................................................................ 13
a. Background.......................................................................................................................... 13
b. Dividing................................................................................................................................ 14
c. Switches................................................................................................................................ 14
3. Diagram of one block............................................................................................................. 14
a. List of useful combinations ................................................................................................ 14
b. Diagram ............................................................................................................................... 15
c. Making useful combinations.............................................................................................. 16
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4. Diagram of 6 blocks ............................................................................................................... 16
a. List of useful combinations ................................................................................................ 16
b. Diagram ............................................................................................................................... 16
c. Making useful combinations.............................................................................................. 17
5. Combination of whole system .............................................................................................. 17
III. POWER CHARGING CIRCUIT WITH MICROCONTROLLER................................. 19
1. Digital expression ................................................................................................................... 19
2. Application circuit .................................................................................................................. 19
CONCLUSION.................................................................................................................................. 20
FUTURE WORK .............................................................................................................................. 21
REFERENCES .................................................................................................................................. 22
APPENDIX ........................................................................................................................................ 23
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LIST OF FIGURES
Figure 1. Solar panel diagram .............................................................................................................9
Figure 2. I-V characteristic of solar panel ...................................................................................... 10
Figure 3. Power – Voltage Characteristic of solar panel .............................................................. 10
Figure 4. Symmetrical Combination Form of n components....................................................... 13
Figure 5. List of useful combinations of 4 panels ......................................................................... 15
Figure 6. Circuit diagram of one block ........................................................................................... 15
Figure 7. List of useful combinations of 6 blocks ......................................................................... 16
Figure 8. Circuit diagram of 6 blocks ............................................................................................. 17
Figure 9. Microcontroller using 3 bits of data ............................................................................... 19
Figure 10. Application circuit .......................................................................................................... 19
Figure 11. Light Meter ...................................................................................................................... 25
Figure 12.Measuring I-V value of one panlel ................................................................................ 25
Figure 13. Outdoor measurement .................................................................................................... 29
Figure 14.Measuring I-V value of 3 solar panels in series........................................................... 33
LIST OF TABLES
Table 1. Switches closed to make useful combination of 4 panels ............................................. 16
Table 2. Switches closed to make useful combination of 6 blocks ............................................. 17
Table 3. Useful combinations of 24 panels made from combinations of 6 blocks and in each
block .................................................................................................................................................... 18
Table 4. Binary bits representing combinations ............................................................................ 19
LIST OF APPENDICES
APPENDIX A. I-V value of Panel 1 under indoor light .............................................................. 23
APPENDIX B. I-V graph of Panel 1 .............................................................................................. 26
APPENDIX C. I-V value of solar panels under outdoor light conditions ................................. 27
APPENDIX D. I-V value of some useful combination of one block under indoor condition 30
APPENDIX E. Mosfet as switch ..................................................................................................... 34
LIST OF SYMBOLS AND ABBREVIATIONS
MPP Maximum Power Point
LED Light Emitting Diode
I-V Current - Voltage
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INTRODUCTION
1. Background
Solar panels are electronic devices used to convert solar energy, a clean and abundant
alternative energy, into electrical energy. It is more and more commonly used in both
industrial and daily life. “Solar panels” is also a major topic at the university level.
When using any energy source, an optimization problem of transferring that energy
into electrical energy is observed. For solar cells, current output has a linear relationship with
voltage, so power delivery has a point of maximum efficiency. Solar panels should work at
this point.
To achieve maximum energy, it is necessary to have a charge controller. It also ensures
that the output parameters of the solar system meet the requirements of the device. There are
two ways to do this: voltage control or current control. Voltage control is easier and is
normally chosen.
2. Object
The object of this project is to make the power charging circuit for a lightweight solar
robot with 24 small size solar panels (5x6 centimetres). This robot works under indoor
condition but not in fixed position. Therefore, the intensity of light that the solar panels
receive is not stable.
The charging circuit has two missions: (1) tracking the maximum power point of all
small solar modules as well as whole system and (2) ensuring the output voltage of charging
system meets the required voltage of the robot.
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I. SOLAR PANEL AND CHARGE CONTROLLER
1. Solar panel
a. Background
Solar energy is the Earth’s main source of energy, which is not only transmitted to
Earth via light and heat radiation but also the source of many other types of energy like wind
power, water power, and biomass. Humans often make use of these secondary energy
sources. However, directly transforming solar energy into electrical energy is entirely
possible. Solar panels are the tool for that process.
Solar cells or photovoltaic cells (PV) use the photovoltaic effect to converts light into
electric current. Nowadays, the major material used for manufacturing solar cells (and for
semiconductor devices) is crystalline silicon. A solar panel (also solar module, photovoltaic
module or photovoltaic panel) is a packaged, connected assembly of solar cells.
When the panel with a semiconductor p-n junction is exposed to the sunlight, the
photons from the sunlight stimulate more electron – hole pairs. If electron – hole pairs are
close to the p – n junction, the voltage will push the electron exposure of one party (the
semiconductor n) and push hole on the other side (the semiconductor p). Electrons jumping
from valence domain to conduction domain can move freely. The more photons that the solar
panel receives, the more opportunity there is for electrons to jump. If we use an outside wire
to connect n-type semiconductor with p-type semiconductor (via a load such as compacting
LED), there is a current of electrons that follows that direction. Therefore the solar energy of
the light is converted into electrical energy of electrons.
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Figure 1. Solar panel diagram
<http://www.about-solarenergy.com/wp-content/uploads/2011/10/how-solar-
power-work.png>
b. Characteristics
There are two main points of solar panel’s characteristics.
First, when the intensity of light is stable, the output current and voltage of solar panel
have non-linear relationship.
These below graph show my measurement’s result. I worked with one 5x6 centimeter
size amorphous silicon solar cells under many light conditions.
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Figure 2. I-V characteristic of solar panel
Figure 3. Power – Voltage Characteristic of solar panel
0 1 2 3 4 5 6 70
100
200
300
400
500
600
Po
we
r (µ
W)
Voltage (V)
256 lux
315 lux
417 lux
561 lux
631 lux
720 lux
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Now we consider each line in Figure 2. At first, when the load resistance value is 0 Ω,
the output voltage is 0 V. When the load resistance value increases, the output voltage
increases as the current falls down. The current will be 0 A when the load is infinite.
Therefore, there is a point in which I*V is maximum i.e. the delivery power is
maximum. I call it Maximum Power Point (MPP). It is clearly visible in the Figure 3. The
solar panel should be controlled to work at this point.
Second, when the intensity of light changes, the electrical parameters of the solar panel
change immediately.
In photovoltaic effect, the opportunity there is for electrons to jump to conduction
domain and move freely depends on how many photons that the solar panel receives.
Therefore, when the light intensity is not stable, the number of photons coming change and
leads the electron current changes.
The brighter light, the higher open circuit voltage, short circuit current and maximum
power. In my measurement, when the light intensity rises from 256 to 720 lux, the m aximum
power point of solar panel increase from 190.464 to 600.237 µW.
One key point is that the maximum power point of solar panel under brighter light is
tracked at higher voltage. Therefore, if we keep the certain voltage, we cannot get the
maximum power under different light conditions.
2. Charge controller
a. Motivation
Because of the nonlinear relationship between current and voltage output of solar
panel, we need to ensure that the panel works at MPP (the load line intersect the I-V
characteristic at MPP).
The electrical parameters, especially voltage of solar panel, are not stable even though
most electric devices need stable supply voltage. For example, when an array of panels is
used to charge some batteries, the excessive voltage can damage the batteries. As the voltage
from the array rises, the charge to the batteries should be regulated to prevent any
overcharging. Therefore, it is necessary to maintain the output voltage of a solar charging
system.
Those two simple reasons show that the charge controller has important role.
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b. Solution
In this project, a solar charging system with 24 solar panels is used to supply an indoor
solar robot. This robot requires a stable voltage source (1.8 to 3.6 volts). Two issues have
been outlined above: achieving maximum power point and keeping a stable output voltage.
To solve those problems, a charging circuit is built to combine solar panels in many
different ways. Each way provides different voltage value. Different combinations of panels
are created by flipping switches between them. However, not all of combinations satisfy two
conditions. We need to find the useful ones.
Each switch in the circuit is one Mosfet. They can be switched by controlling the
voltage in the Gate terminals. This function is performed by a low power microcontroller. The
microcontroller senses a light density and target voltage for two purposes: to find the suitable
combination of solar panels and to drive the Mosfets to make that combination.
This project focuses on building power charging circuit.
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II. POWER CHARGING CIRCUIT
1. Purpose
The purpose of the charging circuit is to combine the solar panels in suitable way to
get the target voltage output.
There are a lot of combinations for 24 panels. However, not all of them are useful. We
have to find useful combinations.
2. Initial principle
a. Background
There are some required conditions that the circuit has to ensure:
- The output voltage must be close to target voltage
- Each panel and whole system must work at MPP
Suppose that there are n panels. All of them have the same MPP at a given voltage V
and current I (the maximum power in Watts is ). The theoretical maximum power of the
system with n panels is (Watts).
The combinations which satisfy two conditions above must be symmetrical . In general,
the form of a symmetrical combination is:
Figure 4. Symmetrical Combination Form of n components
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There are a columns and b rows of solar panels ( ). With each pair of a and b,
there is one combination. In all below part, I name the symmetrical combination having a
columns and b rows by [a, b].
The output current and voltage at maximum power point of whole system are
(amperes) and (volts). The maximum power is:
.
Therefore, the maximum power of this combination is the maximum power possible
when we connect n panels. That is why this is a useful combination.
b. Dividing
To simplify the diagram, I divide 24 panels into 6 blocks. Each block has 4 panels. The
combinations of 24 panels can be made from different combinations in each block and in the
connection between the 6 blocks.
Because 24 panels must be in symmetrical combination, the combination of 4 panels in
each block and combination of 6 blocks must be symmetrical.
c. Switches
Different combinations of charging circuit can be made by flipping the switches put
between solar panels. In the real circuit, we cannot turn the switches on or off by hand. It is
automatically controller by microcontroller. I suggest to use Mosfets as the switches. A
Mosfet can be seen as a switch whose state depends on the voltage of its Gate terminal. The
microcontroller changes that voltage to drive the Mosfet.
3. Diagram of one block
a. List of useful combinations
Because , there are 3 useful combinations for one block
with 4 panels.
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Figure 5. List of useful combinations of 4 panels
b. Diagram
Figure 6. Circuit diagram of one block
The circuit has 2 terminals (A, B) and 9 switches.
Solar panel Switch
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c. Making useful combinations
To make each useful combination, corresponding switches shown below must be
closed and all other are opened.
No. Combination Switches Closed
1. [1,4] 1,2,7,5,6,9
2. [2,2] 1,2,3,4,6
3. [4,1] 3, 8,4
Table 1. Switches closed to make useful combination of 4 panels
4. Diagram of 6 blocks
a. List of useful combinations
Figure 7. List of useful combinations of 6 blocks
In this case, so there are 4 useful symmetrical
combinations. Suppose that all blocks have the same MPP tracked at given voltage V0 and
current I0.
block
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b. Diagram
Figure 8. Circuit diagram of 6 blocks
This circuit has 2 terminals and 15 switches.
c. Making useful combinations
No. Name of combination Switches Closed
1. [1,6] 1,2,5,6,9,10,11,12,13,14
2. [2,3] 1,2,3,4,6,7,8,10
3. [3,2] 1,3,4,7,8,10
4. [6,1] 3,4,7,8,15
Table 2. Switches closed to make useful combination of 6 blocks
5. Combination of whole system
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There are 8 useful combinations. Each useful combination of 24 panels can be built by
using useful combinations of 6 blocks, each containing 4 panels that are connected in useful
way.
No. Combination of 24
panels
Combination of 6
blocks
Combination in each
block
1 [1,24] [1,6] [1,4]
2 [2,12] [2,3] [1,4]
3 [3,8] [3,2] [1,4]
4 [4,6] [1,6] [4,1]
5 [6,4] [6,1] [1,4]
6 [8,3] [2,3] [4,1]
7 [12,2] [6,1] [2,2]
8 [24,1] [6,1] [4,1]
[m*x, p*y] [m, p] [x, y]
Table 3. Useful combinations of 24 panels made from combinations of 6 blocks and in
each block
In the order listed, the MPP voltages of the combinations increase while the current
decreases. However, the theoretical maximum power of all combination is 24 times those of
each panel. That is an optimistic number. In total, the charging circuit has 69 Mosfets.
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III. POWER CHARGING CIRCUIT WITH MICROCONTROLLER
1. Digital expression
The combinations of the power charging circuit must be converted into digital signal
so that the microcontroller can understand and process them.
There are 8 useful combinations of the 24 panels. It is possible to represent 8 states
with 3 bits of data.
Figure 9. Microcontroller using 3 bits of
data
Bit combinations
000 100
001 101
010 110
011 111
Table 4. Binary bits representing
combinations
2. Application circuit
Figure 10. Application circuit
Microcontroller
Vmeas
SYSTEM
24 solar panels
+ microcontroller
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CONCLUSION
The project’s object is to build the power charging circuit for a lightweight indoor
robot using 24 small size solar panels. The current and voltage output of solar panel have
non-linear relationship and these parameters change immediately when the light intensity
changes. Therefore, there are two required conditions: (1) the output voltage must be
maintained to meet required voltage of the robot and (2) each panels and whole system must
work at maximum power point.
To satisfy first conditions, the charging circuit is made so that its combinations can be
changes. At each light condition, the suitable combination supplying the target voltage is
chooses. This function is performed by a low power microcontroller.
There are switches which are Mosfets between solar panels. Each combination of
charging circuit can be made by closing corresponding switches and opening all others. The
states of Mosfet depend on the voltage in its Gate terminal and the microcontroller controls
this voltage to drive Mosfets.
The solution for second condition is connecting solar panels in symmetrical way with a
columns and b rows. The symmetrical combinations are useful because its maximum power
point is the sum of all those of all the panels.
To simplify the diagram, 24 panels are divided into 6 blocks, each block has 4 panels.
There are 3 useful symmetrical combinations of 4 panels, 4 those of 6 blocks and 8 those of
24 panels. Each symmetrical combination of 24 panels is a coordination of one symmetrical
combination in each block and one symmetrical combination between 6 blocks.
In conclusion, the power charging circuit has 24 solar panel connected in
symmetrical combination. There are 8 combinations possible. The microcontroller then uses 3
bits of data to represent and select the combination.
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FUTURE WORK
1. Construction of real charging circuit
In total, the power charging circuit includes 24 solar panels, 69 Mosfets as switches
and wires. They are connected follow the diagram shown in the report. Furthermore, the
connection must be scientific so that the charging system is not too big and is easily brought
by the robot. We can optimize the size of charging circuit as 30x40 centimeter.
2. Program a low power microcontroller
The microcontroller is used to control the whole robot and controlling the charge
controller is a part of this. The MSP430 Family and CC2500 Radio should be chosen because
they are really low power with a lot of documentations available and interface as well with
each other.
The microcontroller uses 3 bits of data to select one of the 8 combinations. The bits
are then used to open and close the appropriate MOSFET switches.
3. Conduct test experiments to find the best symmetrical combination
After combine charging circuit and microcontroller programmed, we should conduct
test experiment with the application circuit (page.23).
The power output of charging circuit is charge into a capacitor. The microcontroller
changes the value of 3 bits from 000 to 111 really fast (maybe some nanoseconds). The
voltage charged into the capacitor is measured. After many period of changing (from 000 to
111), the best combination with highest maximum power can be defined.
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REFERENCES
[1] Peck Kim Shan, 2011, “Solar Powered Remote Controlled Robot” , Bachelor
Thesis, Department of Electrical and Computer Engineering, National University of
Singapore, Singapore, pp 10-13, 23-24.
[2] Rumit Kumar Singh, 2012, “Antireflective nanostructures for Solar Panel” , Final
Internship Report, Department of Electrical and Computer Engineering, National
University of Singapore, Singapore, pp 29-30.
[3] Wikipedia, “Solar panel”, http://en.wikipedia.org/wiki/Solar_panel, accessed in July
2012.
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APPENDIX
APPENDIX A. I-V value of Panel 1 under indoor light
Panel 1 at 256 lux Panel 1 at 315 lux Panel 1 at 467 lux
Voltage
(V)
Current
(µA)
Power
(µW)
0.00002 58.2 0.001164
0.024 58 1.392
0.432 57.7 24.9264
0.66 57.5 37.95
0.975 57.2 55.77
1.237 57 70.509
1.523 56.7 86.3541
1.882 56.3 105.9566
2.133 56 119.448
2.434 55.5 135.087
2.797 55 153.835
3.069 54.5 167.2605
3.153 54 170.262
3.349 53 177.497
3.486 52 181.272
3.532 51 180.132
3.627 50.5 183.1635
3.784 50 189.2
3.858 49 189.042
3.968 48 190.464
4.032 47 189.504
4.118 46 189.428
4.174 45 187.83
4.203 44.7 187.8741
4.205 44.3 186.2815
Voltage
(V)
Current
(µA)
Power
(µW)
0.00002 90 0.0018
0.049 89.7 4.3953
0.153 89.4 13.6782
0.584 89.2 52.0928
0.95 89 84.55
1.206 88.6 106.8516
1.604 88.3 141.6332
2.111 87.5 184.7125
2.506 87 218.022
2.883 86 247.938
3.136 85 266.56
3.41 83 283.03
3.871 79.5 307.7445
4.048 77 311.696
4.249 74 314.426
4.405 72 317.16
4.539 69 313.191
4.66 66 307.56
4.762 64 304.768
4.828 62 299.336
4.907 60 294.42
4.978 58 288.724
5.036 56 282.016
5.083 55 279.565
5.106 54 275.724
5.111 53.5 273.4385
Voltage
(V)
Current
(µA)
Power
(µW)
0.00002 70.2 0.001404
0.525 70 36.75
0.994 69.7 69.2818
1.215 69 83.835
1.536 68.7 105.5232
1.892 68.3 129.2236
2.167 68 147.356
2.48 67.5 167.4
2.704 67 181.168
2.877 66.5 191.3205
3.038 66 200.508
3.287 65 213.655
3.401 64 217.664
3.555 63 223.965
3.754 62 232.748
3.931 60 235.86
4.006 59 236.354
4.101 58 237.858
4.154 57 236.778
4.213 56 235.928
4.282 55 235.51
4.381 53 232.193
4.455 52 231.66
4.546 50 227.3
4.599 49.5 227.6505
4.613 49 226.037
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Panel 1 at 561 lux Panel 1 at 631 lux Panel 1 at 720 lux
Voltage
(V)
Current
(µA)
Power
(µW)
0.00003 121.5 0.003645
0.075 121.3 9.0975
0.217 121 26.257
0.908 120.5 109.414
1.224 120 146.88
1.616 119.5 193.112
2.081 119 247.639
2.446 118 288.628
2.889 117 338.013
3.208 115 368.92
3.649 113 412.337
4.045 109 440.905
4.22 106 447.32
4.33 104 450.32
4.577 99 453.123
4.745 94 446.03
4.887 92 449.604
5.042 87 438.654
5.122 84 430.248
5.209 80 416.72
5.307 75 398.025
5.337 73 389.601
5.389 69.5 374.5355
5.432 66 358.512
5.461 64 349.504
5.489 62 340.318
5.514 60 330.84
5.526 58.5 323.271
5.53 58 320.74
Voltage
(V)
Current
(µA)
Power
(µW)
0.00003 142.3 0.004269
0.093 142 13.206
0.476 141.5 67.354
0.827 141 116.607
1.362 140.6 191.4972
1.502 140 210.28
1.892 139.7 264.3124
1.945 139.3 270.9385
2.348 139 326.372
2.556 138 352.728
2.846 137.5 391.325
3.136 136 426.496
3.479 134 466.186
3.816 131 499.896
4.129 127 524.383
4.348 124 539.152
4.709 116 546.244
4.934 110 542.74
5.057 106 536.042
5.137 102 523.974
5.256 97 509.832
5.357 91 487.487
5.404 88 475.552
5.453 84 458.052
5.51 79 435.29
5.554 75 416.55
5.585 71.5 399.3275
5.622 67 376.674
5.655 63 356.265
5.677 60 340.62
5.681 59.5 338.0195
5.689 59 335.651
Voltage
(V)
Current
(µA)
Power
(µW)
0.00003 155.6 0.004668
0.098 155.3 15.2194
0.236 155 36.58
0.966 154 148.764
1.537 153.5 235.9295
1.722 153 263.466
2.299 152 349.448
2.618 151 395.318
2.996 150 449.4
3.373 147 495.831
3.75 144 540
4.139 139 575.321
4.375 135 590.625
4.653 129 600.237
4.907 122 598.654
5.025 118 592.95
5.235 109 570.615
5.346 102 545.292
5.393 99 533.907
5.447 95 517.465
5.489 91 499.499
5.532 87 481.284
5.557 84 466.788
5.609 78 437.502
5.633 75.5 425.2915
5.662 71 402.002
5.686 68 386.648
5.707 65 370.955
5.733 61 349.713
5.738 60 344.28
Solar Panel Charge Controller 2012
25 |Ngo Khac Hoang
Figure 11. Light Meter
Figure 12. Measuring I-V value of one panel
Solar Panel Charge Controller 2012
26 |Ngo Khac Hoang
APPENDIX B. I-V graph of Panel 1
Panel 1 at 256 lux
Panel 1 at 315 lux
Panel 1 at 467 lux
Panel 1 at 561 lux
Panel 1 at 631 lux
Panel 1 at 720 lux
0 1 2 3 4 50
50
100
150
200
Cu
rre
nt
& P
ow
er
Voltage (V)
Current (µA)
Power (µW)
0 1 2 3 4 50
50
100
150
200
250
Cu
rre
nt
(µA
)
Voltage (V)
Current (µA)
Power (µW)
0 1 2 3 4 5 60
50
100
150
200
250
300
350
Cu
rre
nt
& P
ow
er
Voltage (V)
Current (µA)
Power (µW)
0 1 2 3 4 5 60
100
200
300
400
500
Cu
rre
nt
& P
ow
er
Voltage (V)
Current (µA)
Power (µW)
0 1 2 3 4 5 60
100
200
300
400
500
600
Cu
rre
nt
& P
ow
er
Voltage (V)
Current (µA)
Power (µW)
0 1 2 3 4 5 60
100
200
300
400
500
600
Cu
rre
nt
& P
ow
er
Voltage (V)
Current (µA)
Power (µW)
Solar Panel Charge Controller 2012
27 |Ngo Khac Hoang
APPENDIX C. I-V value of solar panels under outdoor light conditions
Panel 4 under cloudy condition Panel 5 under slight sunny condition
Light
intensity (lux)
Voltage
(V)
Current
(mA)
Power
(mW)
2530 0.0027 0.77 0.002079
2500 0.0028 0.76 0.002128
2460 0.374 0.74 0.27676
2430 1.105 0.73 0.80665
2550 2.49 0.72 1.7928
2400 3.68 0.7 2.576
2540 4.41 0.69 3.0429
2400 5.03 0.63 3.1689
2520 5.51 0.66 3.6366
2430 5.78 0.49 2.8322
2460 5.99 0.44 2.6356
2520 6 0.44 2.64
2500 6.08 0.36 2.1888
2540 6.14 0.32 1.9648
2570 6.18 0.3 1.854
2500 6.2 0.39 2.418
2460 6.24 0.39 2.4336
2440 6.28 0.35 2.198
2430 6.32 0.31 1.9592
2430 6.39 0.2 1.278
2450 6.41 0.19 1.2179
2460 6.42 0.18 1.1556
2470 6.44 0.16 1.0304
2470 6.45 0.15 0.9675
2430 6.45 0.14 0.903
2480 6.47 0.14 0.9058
2480 6.47 0.13 0.8411
2520 6.48 0.13 0.8424
2520 6.48 0.11 0.7128
2550 6.49 0.1 0.649
Light intensity
(lux)
Voltage
(V)
Current
(mA)
Power
(mW)
4370 0.0049 1.425 0.006983
4440 0.0051 1.42 0.007242
4470 0.123 1.42 0.17466
4520 1.383 1.41 1.95003
4560 2.25 1.41 3.1725
4440 5.33 1.22 6.5026
4360 5.65 1.13 6.3845
4410 5.75 1.11 6.3825
4430 6.09 0.93 5.6637
4450 6.19 0.86 5.3234
4560 6.25 0.81 5.0625
4490 6.33 0.7 4.431
4510 6.37 0.64 4.0768
4510 6.39 0.62 3.9618
4540 6.43 0.58 3.7294
4490 6.44 0.52 3.3488
4560 6.48 0.49 3.1752
4480 6.48 0.44 2.8512
4580 6.51 0.44 2.8644
4450 6.52 0.36 2.3472
4430 6.53 0.33 2.1549
4390 6.55 0.29 1.8995
4370 6.56 0.28 1.8368
4560 6.57 0.26 1.7082
4370 6.72 0.11 0.7392
4410 6.72 0.105 0.7056
4440 6.73 0.103 0.69319
4460 6.73 0.09 0.6057
4510 6.74 0.09 0.6066
4490 6.74 0.09 0.6066
Solar Panel Charge Controller 2012
28 |Ngo Khac Hoang
Panel 5 under sunny conditions Panel 5 under sunniest condition
Light
intensity
(lux)
Voltage
(V)
Current
(mA)
Power
(mW)
55600 0.0879 15.51 1.363329
55600 1.599 14.69 23.48931
55800 6.4 10.37 66.368
55800 6.45 10.49 67.6605
56200 6.51 9.95 64.7745
55700 6.75 7.88 53.19
55400 6.76 7.41 50.0916
56000 6.86 5.57 38.2102
56000 6.87 6.5 44.655
56000 6.93 5.77 39.9861
55600 6.97 5.36 37.3592
55600 6.97 5.36 37.3592
56300 6.98 5.34 37.2732
55900 6.98 5.3 36.994
55800 6.98 5.28 36.8544
55400 6.98 5.11 35.6678
55600 7.02 4.54 31.8708
55800 7.15 1.75 12.5125
56000 7.15 1.74 12.441
55600 7.16 0.25 1.79
55800 7.16 0.13 0.9308
56000 7.16 0.1 0.716
55600 7.19 0.18 1.2942
56300 7.19 0.16 1.1504
56000 7.2 1.19 8.568
55900 7.22 0.19 1.3718
55900 7.25 0.19 1.3775
Light
intensity
(lux)
Voltage
(V)
Current
(mA)
Power
(mW)
84600 0.00543 25.09 0.136239
84800 0.0542 25.04 1.357168
84600 0.0555 25.02 1.38861
84800 0.071 24.72 1.75512
84800 1.273 24.73 31.48129
85000 1.308 24.77 32.39916
84600 1.505 23.47 35.32235
85300 1.71 23.25 39.7575
84600 3.65 23.22 84.753
84800 5.14 23.21 119.2994
84600 5.41 20.32 109.9312
84800 5.87 13.94 81.8278
84800 5.87 13.94 81.8278
85100 6.12 13.85 84.762
85100 6.25 7.3 45.625
84600 6.27 6.62 41.5074
84800 6.48 4.92 31.8816
84800 6.61 5.21 34.4381
85300 6.63 5.14 34.0782
85100 6.65 4.44 29.526
85100 6.72 3.35 22.512
84800 7.03 0.17 1.1951
85300 7.05 0.12 0.846
85300 7.16 0.45 3.222
84600 7.21 0.12 0.8652
85200 7.26 0.1 0.726
84600 7.28 0.18 1.3104
Solar Panel Charge Controller 2012
30 |Ngo Khac Hoang
APPENDIX D. I-V value of some useful combinations of a block under indoor condition
4 panel in series at 704 lux
Voltage
(V)
Current
(µA)
Power
(µW)
0.02 146 2.92
0.235 145.8 34.263
0.74 145.3 107.522
1.135 145.2 164.802
1.564 145 226.78
2.071 144.8 299.8808
2.733 144.5 394.9185
3.202 144 461.088
3.705 143.8 532.779
4.072 143 582.296
4.75 142.8 678.3
5.09 142.8 726.852
5.51 142.7 786.277
6.28 142 891.76
7.14 141.7 1011.738
7.62 141.3 1076.706
8.17 141 1151.97
8.98 140.8 1264.384
9.33 140.5 1310.865
9.96 140 1394.4
10.43 139.8 1458.114
10.85 139.3 1511.405
11.43 139 1588.77
12.21 138.3 1688.643
12.36 138 1705.68
12.67 137.9 1747.193
13.06 138 1802.28
14.06 137 1926.22
14.43 136 1962.48
15.19 134.5 2043.055
15.85 133 2108.05
16.04 131 2101.24
17.16 129 2213.64
17.74 126.5 2244.11
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18.12 125 2265
18.82 120.5 2267.81
19.08 119 2270.52
19.47 117 2277.99
19.98 112 2237.76
20.23 110.3 2231.369
20.25 110 2227.5
20.43 108 2206.44
20.63 106 2186.78
20.87 102 2128.74
21.02 100 2102
21.19 97 2055.43
21.36 94 2007.84
21.54 91 1960.14
21.78 85 1851.3
21.89 82 1794.98
21.99 79 1737.21
4 panels in parallel at 706 lux
Voltage
(V)
Current
(µA)
Power
(µW)
0.07 583 40.81
0.181 582 105.342
0.62 579 358.98
0.931 578 538.118
1.258 576 724.608
1.992 570 1135.44
2.472 566 1399.152
2.674 564 1508.136
3.029 559 1693.211
3.322 553 1837.066
3.966 532 2109.912
4.58 493 2257.94
4.77 475 2265.75
4.82 470 2265.4
5.01 441 2209.41
5.1 423 2157.3
5.26 375 1972.5
5.32 350 1862
5.38 326 1753.88
Solar Panel Charge Controller 2012
32 |Ngo Khac Hoang
5.43 301 1634.43
5.45 287 1564.15
5.48 265 1452.2
5.51 250 1377.5
5.54 223 1235.42
5.56 210 1167.6
5.58 197 1099.26
5.6 178 996.8
5.61 170 953.7
5.63 151 850.13
5.66 117 662.22
5.67 104 589.68
5.68 97 550.96
5.69 87 495.03
5.7 76 433.2
5.71 64 365.44
4 panels in 2 columns and 2 rows at 700 lux
Voltage
(V)
Current
(µA)
Power
(µW)
0.03 292 8.76
0.24 291 69.84
0.513 290.8 149.1804
1.178 290 341.62
1.481 289 428.009
1.953 288.3 563.0499
2.107 288 606.816
2.281 287 654.647
2.645 286.5 757.7925
3.196 286 914.056
3.412 285 972.42
3.937 284 1118.108
4.11 283.8 1166.418
4.49 283 1270.67
4.92 282 1387.44
5.19 281 1458.39
5.57 280 1559.6
5.92 278 1645.76
6.29 277 1742.33
6.58 276 1816.08
Solar Panel Charge Controller 2012
33 |Ngo Khac Hoang
6.94 274 1901.56
7.39 271 2002.69
7.76 268 2079.68
8 265 2120
8.07 264.5 2134.515
8.28 262 2169.36
8.58 258 2213.64
8.87 254 2252.98
9.01 252 2270.52
9.18 248 2276.64
9.38 244 2288.72
9.52 241 2294.32
9.73 235 2286.55
10 227 2270
10.1 223 2252.3
10.37 211 2188.07
10.5 203 2131.5
10.78 181 1951.18
10.88 172 1871.36
10.94 165 1805.1
11.01 157 1728.57
11.06 149 1647.94
11.13 139 1547.07
11.2 129 1444.8
11.22 125 1402.5
Figure 14. Measuring I-V value of 3 solar panels in series
Solar Panel Charge Controller 2012
34 |Ngo Khac Hoang
APPENDIX E. Mosfet as switch
n-type MOSFET as switch
<http://www.physics.udel.edu/~watson/scen103/mos4.html>
p-type MOSFET as switch
<http://www.physics.udel.edu/~watson/scen103/mos5.html>