This document refers to industrial attachment carried out at mesh power rwanda in way of fulfill of the university of rwanda terms and regulations where every student in third year must do academic internship in order to improve and enhance his/her practical skills.

1. university of rwanda
college of science and technology
Department electronics and
telecommunication engineering
INTERNERSHIP REPORT
DONE AT MESHPOWER RWANDA
SUBMITTED BY:
GEREDI NIYIBIGIRA

2. i
DECLARATION
My name is Geredi NIYIBIGIRA and I am a Junior at University of Rwanda
College of Science and Technology(UR/CST) I am doing Electronics and
telecommunication Engineering(ETE). Hereby declare that this industrial
attachment training report held at MeshPower Rwanda from 02/03/2021 up to
08/05/2021 in academic year 2019-2020, this is my own work and has not ever
been presented or submitted to any other universities or institutions of high
learning forward of any.
Student name: Geredi NIYIBIGIRA
Reg. number: 218007257
Sign: ……………………………… Date: ……/….... /2019

3. ii
ACKNOWLEDGEMENT
First of all, I would like to thank the Almighty God for being there for me through
my internship I spent at MeshPower, mercy and blessings throughout my life. I
would like also to express my sincere gratitude to the University of Rwanda and
the Government of Rwanda to include practical training in their program.
I really thank my supervising advisor Eng. Nshimiyimana Richard and Meshpower
rwanda’staff especially country manager Jullie and operation manager Cleovis and
others I don’t mention in this report.
I am deeply appreciating the Meshpower Rwanda for accepting to supplement my
practical skills through the practical I carried out there. I thank the production team
(engineers and technicians) who helped me a lot during my internship by sharing
me their skills.
Bringing up the rear, I wish to extend my deep sense of gratitude to my parents,
family, friends, and colleagues for their assistance and encouragements during my
internship. May the Almighty God bless you all.

4. iii
CERTIFICATION
This is to certify that Geredi NIYIBIGIRA has completed his industrial attachment
Done at Meshpower Rwanda located in Gasabo district( kimihurura sector KG 28)
during 10 weeks, from 02/03/2021 to 08/05/ 2021 in partial fulfillment of the
requirement for the award of bachelors in electronics and telecommunication
engineering, as it is essential for every undergraduate junior student in university
of Rwanda, college of science and technology (electronics and telecommunication
engineering), during the Academic year 2020/2021.
Supervisor name: Nshimiyimana Richard
Signature …………………………. Date……/……. /2021

5. iv
TABLE OF FIGURES
Figure 1: theoretical session with eng. Richard ........................................................................................4
Figure 2. fluid vs electricity.....................................................................................................................7
Figure 3: ac current vs dc current Figure 4: dc to ac circuit board ...............................8
Figure 5: digital multmeter ......................................................................................................................9
Figure 6: PV Cell internal architecture...................................................................................................10
Figure 7: charge controller.....................................................................................................................11
Figure 8: Inverter...................................................................................................................................12
Figure 9: battery....................................................................................................................................13
Figure 10: battery bank..........................................................................................................................14
Figure 11: Solar Cells connected with battery bank................................................................................23
Figure 12 Lithium battery......................................................................................................................23
Figure 13: CPE(Customer premises equipment)....................................................................................24
Figure 14 BTS front view ......................................................................................................................24
Figure 15 Internal structure(view) of BTS..............................................................................................25
Figure 16: workshop session(LEDs opening) .........................................................................................27
Figure 17 LED light ..............................................................................................................................27
Figure 18 Hot air gun and soldering station............................................................................................28
Figure 19: LEDs fixing session..............................................................................................................29
Figure 20 checking the broken ones and good ones................................................................................30
Figure 21 Marking the lamp piece which have broken ...........................................................................30
Figure 22 put aside the dead ones and keep those are working ...............................................................30
Figure 23 Discharging batteries by loads(for example this LEDs) ..........................................................31

6. v
TABLE OF CONTENTS
DECLARATION ..........................................................................................................................................i
ACKNOWLEDGEMENT ............................................................................................................................. ii
CERTIFICATION.................................................................................................................................. iii
Supervisor name ...............................................................................................................................iii
TABLE OF FIGURES.................................................................................................................................. iv
TABLE OF CONTENTS ............................................................................................................................... v
ABSTRACT ...............................................................................................................................................1
LIST OF ABBREVIATION AND ACRONYMS ....................................................................................2
CHAP I. BACKGROUND INFORMATION...........................................................................................3
1.1 BACKGROUND..........................................................................................................................3
1.2 GOALS OF INDUSTRIAL ATTACHMENT................................................................................3
1.2.1 GENERAL OBJECTIVES.......................................................................................................3
1.2.2 SPECIFIC OBJECTIVES ........................................................................................................4
1.3. SKILLED ACQUIRED ..............................................................................................................4
1.3.1 THEORITICAL SKILLS.........................................................................................................4
1.3.2 PRACTICAL SKILLS..............................................................................................................4
1.3.3 TRAINING ASSESSMENT .....................................................................................................4
CHAP II. GENERAL INTRODUCTION ................................................................................................5
2.1. INTRODUCTION ......................................................................................................................5
2.2. OVER VIEW ON MESHPOWER RWANDA...........................................................................5
2.2.1. MAIN DISTRIBUTION AND MAINTENANCE...................................................................5
2.3. INTRODUCTION TO ELECTRICITY ....................................................................................6
2.4. FLUID MOTION Vs ELECTRICITY.......................................................................................7
2.5. DIFFERENCE BETWEEN AC CURRENT AND DC CURRENT .........................................7
2.6. MULTIMETER..........................................................................................................................8
2.6.1. How to use Multimeter.............................................................................................................9
3. Introduction to Solar PV Systems ........................................................................................................9
3.1. How solar PV systems work .....................................................................................................10
3.2. Solar PV main specifications ....................................................................................................10
3.3. Solar PV maintenance...............................................................................................................11
4. Charging controller............................................................................................................................11
4.1. Charge controller main specifications ......................................................................................11
5.Inverter...............................................................................................................................................12

7. vi
5.1. Inverter main specifications.....................................................................................................12
6. BATTERY........................................................................................................................................12
6.1. Working and Role.....................................................................................................................13
6.2. Connecting batteries .................................................................................................................14
6.3. Battery capacity ........................................................................................................................15
6.3.1. Depth of discharge .................................................................................................................15
6.3.2. State of charge........................................................................................................................15
6.3.3. Charging Modes.....................................................................................................................15
6.4. Symptoms of a dead battery:....................................................................................................16
6.5. Battery main specifications.......................................................................................................16
6.6. Battery maintenance .................................................................................................................17
7. Victron energy Solar PV system monitoring ......................................................................................18
7.1. VRM dashboard overview........................................................................................................18
7.2. VRM Remote console................................................................................................................19
7.3. BMV battery monitor ...............................................................................................................19
7.4. Victron connect App .................................................................................................................20
7.5. How to use Victron connect app...............................................................................................20
7.6. Victron toolkit app....................................................................................................................21
8. Knowledge and skills acquired...........................................................................................................22
Installing the homegrid solar system...............................................................................................22
9. BTS...................................................................................................................................................24
10. The devices BTS contains and their functions ..................................................................................25
11. LEDs Testing ..................................................................................................................................26
12. LEDs fixing.....................................................................................................................................27
12.1. Tools needed............................................................................................................................27
12.2. The process of LEDs fixing:....................................................................................................29
12.3. Sequences of testing batteries: ................................................................................................30
13. Safety..............................................................................................................................................31
13.1. Personal Protection Equipment(PPE) ....................................................................................31
13.2. Safety precautions...................................................................................................................33
14. References:......................................................................................................................................35

8. 1
ABSTRACT
This report contains all activities carried out through the internship period I did at
Meshpower from 02/03/2021 to 08/05/2021. Understanding of solar system
components and their functionality, Capability to diagnose and troubleshoot solar
system issues, how PV solar systems works, solar PV system components and their
roles.

9. 2
LIST OF ABBREVIATION AND ACRONYMS
UR: University of Rwanda
DC: Direct current
AC: Alternating current
BTS: Base Tranciever Station
CPE: Customer premises equipment
CB: Circuit break
PV: Photovoltaic
MPRW: Mesh power Rwanda
P.D: potential different
Voc: Voltage open circuit
SoC: short circuit current
VRM: Victron remote management

10. 3
CHAP I. BACKGROUND INFORMATION
1.1 BACKGROUND
Actually, industrial attachment is just opportunity offered to undergraduate
students in terms of work at firm, company or organization which is usually does
the related things as the field of interns, this is accomplished in limited period of
time. this is recommended that at the end of each degree based level (diploma,
advanced diploma, Bcs, Msc, PhD), the Universities organize industrial attachment
period for their students[1]
It is in this way; UR have aimed to improve the practical skills of their students by
providing internship period in corresponding companies or organizations as the
field of interns.
I started the internship from on 2nd March 2021 and during 10 weeks I spent in
internship I acquired practical skills in solar system especially in installation and
distribution in min grid solar system and experiencing more like how the various
components work and how we should repair them. In addition, I studied how this
min grid system be supplied to the customers and how they pay back that services.
1.2 GOALS OF INDUSTRIAL ATTACHMENT
1.2.1 GENERAL OBJECTIVES
The industrial attachment was established to enable the university student for
enhancing the practical skills in what they had learned in theory during the
lecturing in the class. And this helps the students to acquire knowledge which
transforming what they had learned in class into professional career adventure.

11. 4
1.2.2 SPECIFIC OBJECTIVES
 Understanding the organization structure and technology
 Learn about basic protection of equipment and machines
 Learn about installation of electrical equipment and their maintenance.
 Understanding the wiring network in electrical installation.
1.3. SKILLED ACQUIRED
1.3.1 THEORITICAL SKILLS
 Explanation on different components of solar PV systems and their specific
roles.
 Basic safety measures when working with electrical installations
1.3.2 PRACTICAL SKILLS
Disassembling & Assembling main system components
Resolving simulated issues
1.3.3 TRAINING ASSESSMENT
Practical: Diagnosis and troubleshooting of simulated issues, system components
assembling.
Theoretical: Solar PV components and basic safety
Figure 1: theoretical session with eng. Richard

12. 5
CHAP II. GENERAL INTRODUCTION
2.1. INTRODUCTION
MPRW Ltd. Rwanda (MPRW) is a registered private limited company in Rwanda.
MPRW is developing and operating solar-powered mini-grids used to
provide affordable, reliable, and sustainable solar energy services to the rural
communities. MPRW aims to create economic opportunities for businesses
and families in rural communities by providing electricity services on a PAYG
basis. MPRW is a wholly owned subsidiary under the US-registered company
Xpower inc.
Technically, it is a mingrid company where it provides a solar energy to the people
in some location or region especially in rural areas. actually as we were explained
customer is supplied through long process from power house station to home
customer by providing him/her CPE (Customer Premises Equipment) and in
addition all this process it is controlled remotely(online) through established
system over network.
2.2. OVER VIEW ON MESHPOWER RWANDA
2.2.1. MAIN DISTRIBUTION AND MAINTENANCE
Mesh power Rwanda Ltd is mainly focuses on providing solar energy in form of
mingrid system in particular region has been selected, they install solar panels and
then after choose power house for other components storing such as batteries, BTS,
AC METERS, INVERTERS,…….. after this they start distributing energy to the
customer where the customer is given the CPEs as meter and work as connection

13. 6
between customer and power house or power station. Here a customer is required
to pay this service before he/she uses it.
2.3. INTRODUCTION TO ELECTRICITY
Electricity is the flow of electric charge carried by (electron) in a conductive
material through an electronic material.
Electricity is characterized by three components: Current, Voltage and
resistance.
● Current (I) is the rate of flow of electric charge per unit time, past a point in
a circuit and its unit is Ampere(A)
1 A = 1000mA (Milliampere or Milliamp)
1kA (Kilo ampere or Kilo amp) = 1000A
● Voltage (V) or Potential Difference (p.d.) is the pressure from an electrical
power source that pushes charged electrons through a conducting loop,
enabling them to do work such as illuminating a light. Voltage is measured in
volts (V).
1V= 1000mV(Millivolt)
1kV (Kilovolt) = 1000V
● Resistance (R) is tendency to resist to the flow of electric charges in a circuit
Resistance is measured in ohm(Ω)
○ 1Ω=1000mΩ(Milli-ohm)
○ 1KΩ=1000Ω(Kilo-ohm) Other must know components are electrical Energy
and Power In general, Energy can be defined as the ability of a physical
matter to do work
● Power is the rate at which work is done or electric energy is transformed
into another form of energy. Simply, it is a measure of how much electric
energy is used in a span of time and it is measured in Watt(W) ○
1W=1000mW(Milliwatt) ○ 1kW(Kilowatt)=1000W
● Electrical energy is the energy generated by movement of electrons from
one point to another and it is measured in Watt Hour(Wh) ○ 1wh=1000
mWh(Milliwatt hour) ○ 1KWh(Kilowatt hour)=1000Wh

14. 7
Example uses of electrical energy: Lighting, cooling, heating. Operating
appliances, electronics, computers, machinery.
2.4. FLUID MOTION Vs ELECTRICITY
Here in order to understand well the what and electricity works we can do this by
comparing it by fluid flow as it is stated in picture below.
Figure 2. fluid vs electricity
As we see in the above picture the level of water in the tank when it increases also
the flow rate of water increase the same as in electricity where we know that when
the voltage increase also the current flow increase.
2.5. DIFFERENCE BETWEEN AC CURRENT AND DC CURRENT
Alternating current (AC) is an electric current with Electric charge flow that
changes direction periodically. On the other hand, In direct current (DC), the
electric charge only flows in one direction.

15. 8
Figure 3: ac current vs dc current Figure 4: dc to ac circuit
board
Alternative current(AC) Direct current(DC)
Amount of energy that
can be carried
Efficient to transmit over
long distances because
the voltage can be
stepped up and current
reduced thus, maintaining
the same power and
minimizing power losses
Not for efficient long
distance transmission
because it requires thick
cables to minimize losses
which is not easily
feasible
Direction Electron flow keep
switching directions -
forward and backward
Electron moves in one
direction or 'forward'
Obtained from A.C Generator and mains Cell or Battery
Flow of Electrons It reverses its direction
while flowing in a circuit
It flows in one direction
in the circuit
2.6. MULTIMETER
Multimeter: this is an electronic device which basically used to measure the
different parameters like resistance, voltage, current, capacity and so on.

16. 9
2.6.1. How to use Multimeter
● Set the mode to V with a wavy line if you’re measuring AC voltage or to the V
with a straight line if you’re measuring DC voltage.
● Make sure the red probe is connected to the port with a V next to it.
● Connect the black probe to COMM port
Figure 5: digital multmeter
● Connect the red probe to the positive side of your component, which is where the
current is coming from.
● Connect the common probe (black) to the other side of your component.
● Read the value on the display.
In the example illustrated on the picture, we’re measuring the voltage of a 1.5V
battery. You know that you’ll have approximately 1.5V. So, you should select a
range with the selection knob that can read the 1.5V. So you should select 2V in
the case of this multimeter and always select the value that a bit greater than the
expected one.
Note: If the range you’ve selected is lower than the real value, you will not get the
correct value and in some instances the multimeter may get damaged. So always
make sure to know the expected voltage across the points you are measuring. If
you select a higher range, you’ll be able to read the value of the voltage, but with a
bit less accuracy.
3. Introduction to Solar PV Systems
Solar PV System: refers to process of generating and distributing solar energy
(from the sun) by using the main tool which is called solar panel here Photovoltaic
cells absorb the sun’s energy and convert it to DC electricity.

17. 10
3.1. How solar PV systems work
Solar PV system works through the following process as they stated below:
● When solar radiations heat a solar cell, electrons start moving, thus creating
electricity.
i. The electricity produced by a solar panel is the sum of electricity produced
by all solar cells that make it.
ii. The electricity produced by a solar panel is DC and it can be directly used or
converted to AC depending on what you are going to do.
Figure 6: PV Cell internal architecture
The main part and essential tool in this system is Solar panel or PV module
where it converts sun radiation into DC electricity
3.2. Solar PV main specifications
 Open-circuit voltage(Voc): The voltage read at PV module terminals, when
disconnected from any circuit.
 Short-circuit current(Isc): Current generated by PV module when the
positive and negative terminal are connected together
 Maximum or peak power: The highest power that a PV module can
generate, assuming the irradiance of 1 KW per hour and per meter squared,
under 25°C ambient temperature and AM 1.5 (Air mass)
 It is expressed in Watt Peak(Wp)

18. 11
3.3. Solar PV maintenance
 Remove any debris fallen of solar panels
 Clean the solar panels using clean water and scrubbing a soft brush
 Cut growing tree branches that may shade the solar panels in the near future.
Note: Solar panels should be cleaned in early morning or later evening after sunset,
when they are not hot. The solar panel glass is made of tempered glass and
changing temperatures abruptly from hot to cool can crack it.
4. Charging controller
When we are producing the high quantity of voltage
that why we really need to control it. In this
way we need to use what we call the solar charge
controller. the solar charge Controllers main task is
to charge the battery and to protect it from
overcharging and deep discharging. Deep
discharging could also damage the battery. Charge
controllers manage interactions and energy flows
between a PV array, battery bank, and electrical
load.
4.1. Charge controller main specifications
 Maximum charging current:
 The maximum current a charge controller can put into battery
bank
 Maximum PV voltage:
 Maximum PV voltage it can handle at its input
Figure 7: charge controller

19. 12
 Nominal battery voltage:
 The nominal voltage a charge controller can handle from
battery bank
5.Inverter
Inverter is an electrical device that convert direct current(DC) from battery or PV
array to alternative current(AC)
Figure 8: Inverter
5.1. Inverter main specifications
 DC voltage:
○ The nominal DC input voltage from battery bank
 Continuous power:
○ Nominal power, it can continuously supply to load
 Peak power:
○ Maximum surge power, the inverter can supply to load for a short
period. Usually a few seconds up to 15 minutes.
 Maximum efficiency:
○ Efficiency is the ratio of power out to power in, expressed as a percentage.
If the efficiency is 90 percent, 10 percent of the power is lost in the inverter
6. BATTERY

20. 13
6.1. Working and Role
Battery is an electrochemical device that converts electrical energy to chemical
energy and can reverse the process. Its role is to store energy (electrical charge)
when solar panels get enough solar radiation, to be used in the absence of sun or
other source of energy.
A simple battery model was implemented to quantify the potential for small battery
units to provide increased self-consumption. The battery has a maximum storage
capacity and a lower state-of-charge (SOC) limit, set to 40 % of the maximum
capacity, which the depth of discharge must not pass below to prolong the battery
lifetime. Charging and discharging are subject to losses of 10 %, respectively. The
model is simplified in the respect that it allows unlimited discharge and charge,
independent of the current SOC, in contrast to more physically detailed models.
For this initial evaluation, where the focus is on the respective impacts of load
shifting and battery storage and not on detailed battery performance, the simplified
approach was deemed sufficient[2].
Figure 9: battery

21. 14
Figure 10: battery bank
6.2. Connecting batteries
Series configuration Parallel configuration
● In series there is only one path ● In parallel there is several
paths for current flow
for current flow
● Any source of energy in series ● Any source of energy in
parallel
increases the current while the voltage increases the voltage while
remains the same. the current remains the same

22. 15
6.3. Battery capacity
● A measure of a battery’s ability to store or deliver electrical energy, expressed in
units of ampere-hours. specified at a specific discharge rate, or over a certain time
period.
● Sometimes a battery’s energy storage capacity is expressed in watt-hours (Wh)
example, a nominal 12 volt, 100 ampere-hour battery has an energy storage capacity
of (12 x 100) = 1200 watt-hours
6.3.1. Depth of discharge
● Percentage of capacity that has been withdrawn from a battery compared to the
total fully charged capacity.
● By definition, the depth of discharge and state of charge of a battery add to 100
percent.
● The two common qualifiers for DOD in PV systems are the allowable or maximum
DOD and the average daily DOD
6.3.2. State of charge
● The amount of energy in a battery at the particular time expressed as a percentage
of the energy stored in a fully charged battery.
● Discharging results in a decrease in SOC, charging results in an increase SOC.
● A battery that has had three quarters of its capacity removed, or been `discharged
75%, is said to be at 25% SOC
6.3.3. Charging Modes
● Bulk or Normal: Is typically the first stage of charging. Bulk begins when the sun
comes out. This stage occurs when the batteries are at a lower state-of-charge,
generally anything less than 80% full. The Bulk stage basically allows the solar panel
to put as much amperage into the batteries as possible. As the batteries collect
electricity, the voltage will slowly rise over time.
● Absorption: Occurs up to between 80 and 90% state of charge Typically, when a
battery reaches this stage they are around 80-90%. During this stage, the batteries
are kept at the constant voltage, and the amperage going into the batteries reduces as
the batteries become more full.

23. 16
● Float or Finishing Charge: upon the completion of the Absorb stage, the charge
controller will drop the voltage to a preset value and begin the Float stage. The
batteries achieve float stage when they are at 100% charge
6.4. Symptoms of a dead battery:
● Easily charged and discharged
● Cannot be charged
● Unequal cell voltages Causes of battery failures:
● Sulfation (Due to prolonged partial state of charge and this decreases the capacity
of the battery by reducing the size of battery active material)
● Dried up battery electrolyte
● Stratification (Due to increase of concentration of the electrolyte from the bottom
to top of a cell and results in bottom of the cell being consumed, thus reducing battery
life and capacity.
● Loose connections at the terminals (Causes the battery to be undercharged)
● High battery temperature (Requires keeping low the ambient temperature)
● Leakage of electricity due to acid surface between battery terminals (A regular
cleaning of the battery is mandatory)
● Corrosion (Battery terminals may experience corrosion due to the action of
electrolyte gassing from the battery, generally require periodic cleaning and
tightening)
6.5. Battery main specifications:
● Voltage: The total cells voltage
● Capacity: The ability to store energy expressed in Amp-hours(Ah)
● Life cycle: A full charge/discharge of a battery is is called a cycle. Life cycle is
the number of cycles the battery can experience before it fails to meet specific
performance criteria. Cycle life is estimated for specific charge and discharge

24. 17
conditions. The actual operating life of the battery is affected by the rate and depth
of cycles and by other conditions such as temperature and humidity. The higher the
DOD, the lower the cycle life..
● Ability to deep discharge: Is the ability of batteries to be discharged to a low State
Of Charge(SOC) or in other words to a high Depth Of Discharge(DOD)
● C-rate: Is the measure of the rate at which a battery is charged or discharged
relative to its capacity. A 1C rate of a 100Ah battery means that is can get fully
discharged during 1 hour, means a load of 100A during 1 hour.
6.6. Battery maintenance
● Check cable connections to terminals and tighten them if found loose
● Check battery terminals for corrosion and if yes
○ clean them following these steps:
■ Switch off all disconnect and circuit breakers
■ Disconnect cables from batteries
■ Mix some baking soda powder and water and thoroughly stir.
■ Dip a brush into the mixture and scrub the terminals of the battery to
remove corrosion buildup. A toothbrush can be used
■ Rinse the battery terminals with a soft cloth.
■ Clean the cable lugs following the same steps as for battery terminals.
○ Clean any dirt on top of batteries with a soft wet rag.
● For flooded batteries
○ Check the level of electrolyte and refill the battery with distilled water if the
electrolyte is below the indicated minimum level or is not above the plates.
○ Clean any electrolyte leakage on batteries
■ First of all neutralize the acid by pouring baking soda on the battery
surface where the electrolyte is.
■ Pour a small amount of water on the baking soda and wait for a few
seconds for the mix to react.

25. 18
■ Rinse away the mix with a soft rag
● Note: Avoid any water entering inside the battery and never lay any metal tools
on top of batteries.
7. Victron energy Solar PV system monitoring
In this system (on grid system) in order to control the customer remotely also we
need to control our devices remotely, in this way we use easy and quick way by
using the victron energy management.
Victron Remote Management is a free service provided by Victron Energy to
remotely monitor electrical equipment all over the world. With VRM, daily,
weekly, monthly or even yearly data can be monitored. This is possible via Victron
control systems like Cerbo GX, GX touch, Venus GX and Color Control GX.
7.1. VRM dashboard overview
It shows data for Generation, storage and consumption.
● Solar: Shows the energy and power generated from solar PV
● Battery:
○ The state of Charge
○ The charging current
○ System battery voltage
● Consumption: Shows the energy and power supplied to load
VRM dashboard overview

26. 19
7.2. VRM Remote console
It displays the instant:
● Consumption
○ For DC loads
○ For AC loads
● Generation
● Battery State of charge
● Battery voltage
● Inverter state (charging or inverting)
Note: An account is required to have access to Victron Remote Management tool.
7.3. BMV battery monitor
The essential function of a battery monitor is to calculate ampere hours consumed
and the state of charge of a battery. Ampere hours consumed are calculated by
integrating a shunt resistor. In normal operating mode the BMV displays an
overview of important parameters. The + and – selection buttons give access to
various readouts:
● Battery voltage
● Current:

27. 20
The actual current flowing out of the battery (negative sign) or into the battery (no
sign).
● Power: The power drawn from the battery (negative sign) or flowing into the
battery (no sign).
● Consumed Amp-hours: The amount of Ah consumed from the battery
● State of charge: A fully charged battery will be indicated by a value of 100.0%.
A fully discharged battery will be indicated by a value of 0.0%.
7.4. Victron connect App
It helps Get real-time and historical data of any Victron product via Bluetooth,
USB or local area network via GX Devices. Victron Connect works on iOS,
Android phones as well as on Windows and Mac computers.
7.5. How to use Victron connect app:
● Download and install the app
● Open it
● Choose Local or VRM

28. 21
○ Local displays GX devices locally connected to the system
○ VRM displays all GX devices connected with your VRM account
● Open GX devices individually for the systems you want to monitor
7.6. Victron toolkit app
The victron toolkit app is used to:
● calculate cable size and voltage drop. Easily select cable length, amperes and
cable cross section to determine the voltage drop over the cable.
● Understand all LED codes from Victron Energy Multi and Quattro inverters and
different types of chargers and charge controllers
● Temperature derating. Calculate output power derating for inverters and chargers
for the expected ambient temperature.
N.B during our internship we focused on LED definition

29. 22
1. Open the app
2. Choose LED definitions
3. Choose the device you want to troubleshoot
4. Scroll through the list of all possible codes or select the LEDs that blink the
same way as what you see on the device you are troubleshooting.
The app contains normal operation codes, warnings, alarms and error codes.
8. Knowledge and skills acquired
in this internship I have acquired skills I had anticipated before even though there
were some inconveniences mainly caused by the chaos of covid-19 but we tried
our best with help from mesh power staff. Some of those skills and knowledge are:
Installing the homegrid solar system
1.1. Generating
In generating is mainly contained by producing dc voltage by using pv solar panel
through accumulating the solar radiation from the sun. in this section I worked in
installing the solar panel and how they are connected to the other corresponding
devices. During my internship we used the of only two big solar panels or solar
cells.

30. 23
Figure 11: Solar Cells connected with battery bank
Here when the solar radiation heats the solar cells there is a starting of moving
electrons which will produce or creating the electricity. Remember these solar cells
produce DC but after producing you can change it into AC whenever you wish. In
this energy conversion we use the electrical devices which is called inverter. This
energy can be used directly to loads or it can also be used after being stored as we
are going to see it in the following section.
1.2. Storing
Then, as long as you want to use this energy when there is not sun radiation for
example at evening, you need after generating the energy as we have seen above
we should store it by using the batteries. You should use battery bank or one
battery depending on the amount energy(voltage) you want to store.
Battery bank: is a group of battery which are put together for storing the certain
amount energy.
Figure 12 Lithium battery
1.3. Distributing

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Here after generating and storing our energy we need also to distribute it to
the customer. In this process we are required to control the amount of
energy we are giving to customer, and protecting our system in modern
way.
As we have seen above the customer must pay the service before he/she use
it. Some devices and equipment needed in supplying and controlling the
power we distribute.
Figure 13: CPE(Customer premises equipment)
9. BTS
This is the main device or complex device in distributing section where we
could say that it acts as the heart central processing) of system, what we
mean here many controlling and protecting process take place here in BTS.
Figure 14 BTS front view

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Figure 15 Internal structure(view) of BTS
10. The devices BTS contains and their functions
1. Power entry Board(PEB):
This is a device which has input port for pv from solar panel as well as input
(DC current) up to batteries, its output goes to the main board.
It is also act as modern circuit breaker and fuse at the same time where it
uses modern technology by using MOSFET (metal oxide semiconductor
field effect transistor) which can be used as switch in system of high voltage
source, in addition it performs this at high frequency.
Also this Power Entry Board it has microcontroller which enable us to
control it remotely
2. Boost convert: this a device which converts voltage from low to high I
mean technically we call it step up (from 24v to 48v).
the importance for this stepping up our voltage is:
 to reduce transmission cost by decreasing section of cable
 to reduce voltage drop
3. Main board: this board acts as central of all these devices where every part
of BTs sends information to main board in order to be controlled.
4. Charge controller: this is another device which takes dc from solar and
give it out to the battery for storing.

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5. Raspberry pi: it is mainly used for storing information and help us to
communicate with BTS remotely under modem with internet access. We can
modify or make any change on way of working of BTS. actually as we have
seen above this system requires a network in controlling it, so this is device,
where we put a simcard with internet access in order to control it online over
long distance. it is connected to modem from main board.
Back plane: this is used as connector between BTS and CPE where it
holds the power distribution board
2. Controlling the system and make flow up of the customers remotely
by using victron remote management system
3. Maintenance and repairing the broken equipment or devices broken
Here as intern I highly participated in LEDs testing and repairing(fixing) where
there were many process we flowed during that time.
11. LEDs Testing
Here we may start with materials we used as stated below:
1. Molex cables
2. CPEs
3. Supplied BTS
4. Wire with crocodile clips attachment
5. LEDs are going to be tested
Therefore, we supplied BTS by any charged battery and then after we take
Molex cables and connect them effectively to the power distribution board to
the respective ports on the CPEs.
After that there are also other ports on CPE we use in connecting LED to CPE,
here we take cables and attaching them with crocodile clips (for catching the
LED’s wires). Eventually, we connect LED to CPE and decide if it work or no by
considering all procedures we have discussed above.

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In brief, when we get a lamp match with all those procedures automatically we
decide it is good for future use and those which are full or half broken we keep it
for repairing them later.
Figure 16: workshop session(LEDs opening)
12. LEDs fixing
In this activities we performed many steps in order to accomplish it. After testing
the LEDs and get the ones needed to be repaired.
Figure 17 LED light
12.1. Tools needed
1. Soldering iron
2. Switching mode power supply
3. Clamp meter
4. Tweezers
5. Hot air gun
6. Soldering station

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Figure 18 Hot air gun and soldering station

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Figure 19: LEDs fixing session
12.2. The process of LEDs fixing:
Testing each broke of lamp (here whole LEDs has 10 broke) each broke contains 5
lamps, so after knowing the good and dead lamps by using either multimeter
(clamp meter) or by supplying it from the CPE, remove those broken ones by using
hot air gun which is at 350 o
C and tweezers, again after removing it, you have
also to make sure it is really working by using the switching mode power supply
(here you must regulate the switching mode power supply at 3 v). after all these
processes of checking the broken lamps and choosing the good ones you have also
to re-put those good ones on LED strip by using hot air gun device through
regulating it at 350 o
C and soldering iron where it is needed.

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Figure 20 checking the broken ones and good ones
Figure 21 Marking the lamp piece which have broken
Figure 22 put aside the dead ones and keep those are working
4. Testing and re-use the batteries
12.3. Sequences of testing batteries:
a. Place a battery on Charging system (blue smart charger)
b. Record the charging starting time
c. Notice the end time when the battery gets full
d. To take the battery off on charging system
e. To connect the battery to BTS
f. At instant time BTS start immediately turn on all the loads and record
the start time
g. At time goes low (BTS also goes low into LVD, then record the finish
time
h. Record the discharging time (end time minus start time).
i. Eventually, categorizing the batteries according to their discharging
duration.

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Figure 23 Discharging batteries by loads(for example this LEDs)
5. Protection either human being or system
13. Safety
13.1. Personal Protection Equipment(PPE)
● Helmet
Protects against:
○ Falling objects
○ Bumping head against fixed objects
○ Contact with exposed beams or pipes
○ Contact with electrical conductors

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● Gloves
Protects against:
○ Burns
○ Cuts
○ Direct hand contact with electrical conductive objects.
○ Contact with hazardous chemicals like battery acid
● Overall
Protects against:
○ Intense heat
○ Splashes of hot metal or other hot liquid
○ Machinery or materials cuts
○ Contact with hazardous chemicals like battery acid
● Shoes
Protect against:
○ Heavy objects falling on or rolling against the foot
○ Exposure to nails or other sharp objects that might pierce the foot
○ Molten metal that might splash on the foot
○ Hot, wet, or slippery surfaces

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13.2. Safety precautions
● Always put on your protection equipment before you start working with
electrical installations.
● Avoid working with energized electrical installations, cut the power off before
starting the work.
● Avoid water at all times when working with electricity. Never touch or try
repairing any electrical equipment or circuits with wet hands. It increases the
conductivity of electric current.
● Always use insulated tools while working
● Avoid laying metal objects, like spanners on batteries because this could short
the positive and negative terminals, resulting in hazardous fire or even explosion.
● While working outside, always create a large space around the working area as
to avoid non staff people to come closer. Use a safety tape to secure the working
zone.
● When working at heights
○ Ladders should be stable and properly secured or tied off

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○ Your climbing harness and shoes have to be very carefully checked before
climbing up.
○ Working on rooftop, make sure to remove all debris, to make it easier to see any
defect of the roof. Walk carefully to avoid slipping.
○ Work only during good weather conditions and avoid extreme heat and working
under rain.
○ Avoid up and down movements to peak equipment, make sure to have someone
to pass you what you need.
● When working on hot sunny days, take short breaks under shaded area and make
sure to have water to drink by your side to keep your body hydrated[3]

42. 35
14. References:
[1] S. Renganathan, Z. A. B. A. Karim, and C. S. Li, "Students’ perception of industrial internship
programme," Education+ Training, 2012.
[2] J. Widén and J. Munkhammar, "Evaluating the benefits of a solar home energy management
system: impacts on photovoltaic power production value and grid interaction," in Proceedings of
ECEEE summer study, 2013.
[3] [Online]. Available: https://www.meshpower.co.rw/index.html.