ENERGY SOURCES · HISTORY · APPLICATIONS · PV BASICS
1.1 Energy Sources — Renewable vs. Non-Renewable
Energy is the capacity to do work. The world's energy sources fall into two fundamental categories based on whether they can be replenished naturally:
ENERGY SOURCES CLASSIFICATION
Nigeria imports over 70% of its energy as fossil fuels. Solar energy is the most abundant renewable resource available across all Nigerian states — 365 days of sunshine opportunity.
1.2 The Photovoltaic Effect — How Solar Panels Work
The photovoltaic (PV) effect was discovered by Edmund Becquerel in 1839. It describes the generation of voltage and current in a material when it is exposed to light. Solar panels exploit this effect using silicon semiconductor cells.
THE PHOTOVOLTAIC EFFECT — ANIMATED
When photons from sunlight strike the solar cell, they knock electrons free from their atoms. The P-N junction creates an electric field that separates these electrons, causing them to flow in one direction — creating direct current (DC) electricity. Many cells connected together form a solar panel.
1.3 Solar Energy in Africa — Why It Matters
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Africa's Solar Advantage
Africa receives some of the world's highest solar irradiance
Nigeria receives 3.5–7.0 kWh/m²/day of solar irradiance. This means a 1m² solar panel can generate 3.5–7 units of electricity daily — enough to charge phones, power lamps, and run fans for an average household. Sub-Saharan Africa has more solar potential than any other region on Earth.
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Energy Access Crisis
Over 90 million Nigerians lack reliable electricity access
Nigeria's national grid frequently supplies less than 4,000 MW for a population of 220 million people — far below the required 30,000+ MW. Solar energy offers a decentralised solution: each household or community can generate its own power without waiting for grid extension.
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Falling Costs
Solar panel prices have dropped 89% since 2010
In 2010, a solar panel cost approximately $100 per watt. By 2024, this had fallen to under $0.25 per watt — making solar cheaper than fossil fuels in most applications. A complete solar lamp system costs less than ₦5,000 and lasts 3–5 years with no fuel cost.
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Entrepreneurship Opportunity
Solar repair and fabrication is a growing market
There are over 10,000 solar technicians needed across Nigeria's rural communities alone. Students who complete this course can set up solar fabrication businesses, offering solar lamps, chargers, and power banks — starting with as little as ₦50,000 in equipment and generating monthly revenues of ₦150,000+.
1.4 Solar Applications
Application
Solar Device Used
Impact
Street lighting
Solar lantern + LED + battery
Community safety; no electricity bill
Phone charging
Solar panel + USB converter
Communication in off-grid areas
Home lighting
Solar lamp system
Extended study hours; kerosene saved
Irrigation pump
Solar pump system
Year-round farming; food security
Medical equipment
Solar power system
Vaccine refrigeration in rural clinics
Education
Solar-charged tablets, lamps
Night study for students
PRACTICAL ACTIVITIES — WEEKS 1–2
✓
Examine 3 different solar devices (lamp, charger, calculator) and sketch their components in your lab notebook
✓
Identify and label parts of a solar lamp: panel, battery, LED board, switch, charge controller
✓
Carefully dismantle a small solar toy; draw and label all components found inside
✓
Take a solar panel outdoors; use a multimeter to measure its open-circuit voltage in full sunlight, partial shade, and indoor lighting
✓
Record results in lab notebook; sketch the panel and write its rated vs. measured voltage
QUIZ — MODULE 1
What is the photovoltaic effect?
MODULE 02 · WEEKS 3–4
Fundamentals of Electricity
VOLTAGE · CURRENT · RESISTANCE · POWER · OHM'S LAW
2.1 The "Solar Language" — Key Electrical Quantities
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Voltage (V)
The electrical "push" or pressure — measured in Volts (V)
Think of voltage like water pressure in a pipe. The higher the voltage, the harder electrons are being pushed around the circuit. Solar panels produce voltages like 5V, 6V, 12V, 18V. A USB charger outputs 5V. A car battery is 12V. The symbol is V and it's measured with a voltmeter (red probe to + terminal).
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Current (I)
The flow rate of electrons — measured in Amperes (A)
Current is like the volume of water flowing through a pipe. A phone charger draws ~1A. An LED lamp draws ~0.3A. A motor might draw 2–5A. Current is measured with an ammeter (placed in series with the circuit). Always check the maximum current rating of your solar panel and charge controller!
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Resistance (R)
Opposition to current flow — measured in Ohms (Ω)
Resistance is like a narrow section of pipe that restricts water flow. Every component in a circuit has some resistance. Resistors are used deliberately to control current. A burnt component often shows very high resistance (open circuit) while a short circuit shows nearly zero resistance. R = V/I.
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Power (P)
Rate of energy use or generation — measured in Watts (W)
P = V × I. A 5V panel producing 1A of current generates 5 watts of power. An LED rated 5W at 5V draws 1A. Power tells you how much energy is consumed per second. A 10W solar panel in good sunlight generates 10 joules of energy every second.
2.2 Ohm's Law — The Master Equation
Ohm's Law describes the relationship between voltage, current, and resistance. It is the single most important equation in electrical engineering:
OHM'S LAWV = I × R also: I = V/R and R = V/I
V = Voltage (Volts) | I = Current (Amperes) | R = Resistance (Ohms)
OHM'S LAW TRIANGLE — COVER ANY ONE TO FIND THE FORMULA
To use the triangle: Cover the quantity you want to find — the remaining two show the formula. Example: Find Current (I) → cover I → see V above R → I = V ÷ R
Battery capacity: 3.7V, 3000mAh = 11.1 Wh of stored energy
Runtime: 11.1 Wh ÷ 5W = 2.2 hours per charge
To charge battery: Need 11.1 Wh ÷ (6V × 0.3A) = ~6.2 hours of sunlight with a 1.8W panel
Better panel: Use a 5W panel → charge time = 11.1 Wh ÷ 5W = 2.2 hours!
2.4 Series vs. Parallel Circuits
SERIES vs. PARALLEL — VOLTAGE AND CURRENT BEHAVIOUR
In solar systems: panels connected in SERIES increase voltage (e.g. two 12V panels → 24V). Panels in PARALLEL increase current (more charging power). Batteries in PARALLEL increase capacity. Always used PARALLEL for LED arrays in solar lamps — if one LED fails, the others continue working.
PRACTICAL ACTIVITIES — WEEKS 3–4
✓
Use a multimeter to measure voltage output of the solar panel at various light intensities (full sun, shade, indoors)
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Connect an LED to the panel; measure current with ammeter in series; calculate power (P = V × I)
✓
Build a series circuit with 3 LEDs; measure voltage across each; verify they add up to total voltage
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Build a parallel circuit with 3 LEDs; measure current through each branch; verify currents add
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Calculate charging time for a 3000mAh battery using a 5V/1W solar panel (show working)
QUIZ — MODULE 2
A solar panel produces 6V and 0.5A. What is its power output?
For our projects, we will use 5V/6V monocrystalline mini panels — they are small, efficient, and produce sufficient voltage to charge lithium-ion batteries via the TP4056 charging module.
3.2 Battery Types
BATTERY COMPARISON — SOLAR PROJECT APPLICATIONS
For our three projects, we will primarily use 18650 Lithium-Ion cells (for the power bank) and lithium polymer (LiPo) packs (for the lamp and fan). Always check polarity before connecting and NEVER short-circuit a lithium battery — it can cause fire.
3.3 Charge Controllers and Protection Modules
THE TP4056 CHARGER MODULE — YOUR MOST IMPORTANT COMPONENT
The TP4056 is the heart of our solar charging projects. It safely charges a single lithium cell from a 5V solar panel. It automatically stops charging when the battery reaches 4.2V, preventing overcharge damage. Cost: ~₦300–₦500 per module.
⚡ Protection Devices — Why They Matter
Blocking diode: Prevents battery from discharging back through the solar panel at night
Fuse: Breaks the circuit if too much current flows — prevents fire and component damage
Voltage regulator: Maintains steady output voltage even when input changes
BMS (Battery Management System): Protects lithium battery from overcharge, over-discharge, over-temperature, and short circuit
PRACTICAL ACTIVITIES — WEEKS 5–6
✓
Identify 5 solar panel samples: state type (mono/poly/thin film), rated voltage, rated current, polarity
✓
Examine 3 different battery types; record nominal voltage, capacity, charge voltage, discharge cut-off voltage
✓
Connect a TP4056 module to a 5V solar panel; connect a 3.7V LiPo battery; observe charge indicators (red/green LEDs)
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Identify and sketch in lab notebook: USB converter, LED driver, blocking diode, fuse, boost converter module
QUIZ — MODULE 3
What does the RED LED on a TP4056 charging module indicate?
MODULE 04 · WEEKS 7–8
Electrical Workshop Skills
SOLDERING · WIRING · BREADBOARD · SAFETY
4.1 Soldering — The Fundamental Skill
Soldering is the process of joining metal components using a filler metal (solder) that melts at a relatively low temperature. Good solder joints are shiny, smooth, and cone-shaped. Bad joints are dull, grainy (cold joints), or blobby.
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SAFETY FIRST: Always wear safety goggles. Keep the iron in its stand when not in use. Never touch the tip — it reaches 350–400°C. Work in a ventilated area (solder fumes are toxic). Never rest the iron on flammable surfaces.
1
Tin the iron tip
Apply a small amount of solder to the clean iron tip. Wipe excess on a damp sponge. The tip should be shiny silver — this is called "tinning" and ensures good heat transfer.
2
Heat the joint (not the solder)
Place the iron tip so it touches BOTH the wire and the pad/surface simultaneously. Hold for 2–3 seconds to heat the joint to soldering temperature.
3
Apply solder to the joint
Touch the solder wire to the junction (NOT to the iron tip directly). It should melt and flow smoothly into the joint. Use just enough — a cone shape about the size of a grain of rice.
4
Remove iron; hold still
Remove the iron but do NOT move the joint for 3–5 seconds while the solder solidifies. Movement creates cold joints (dull, grainy, unreliable connections).
5
Inspect and test
A good joint is shiny and smooth, cone-shaped. Test with a multimeter for continuity. If dull or grainy, reheat and add a tiny amount of fresh solder.
4.2 Using the Multimeter
MULTIMETER FUNCTIONS AND HOW TO USE THEM
The multimeter is your most important diagnostic tool. Memorise the three key rules: (1) Voltage — measure in PARALLEL; (2) Current — measure in SERIES; (3) Resistance — circuit must be POWERED OFF. Breaking these rules can damage the meter or create a short circuit.
PRACTICAL ACTIVITIES — WEEKS 7–8
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Practice 20 solder joints on a prototype board — instructor evaluates shine, shape, and continuity
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Strip and tin 10 wires of different gauges; solder two wires together; heat-shrink the joint
✓
Desolder a component from a discarded PCB without damaging surrounding components
✓
Build a simple LED + resistor circuit on breadboard; verify with multimeter; transfer to PCB and solder
✓
Test continuity of 5 different circuits using multimeter; check polarity; record results in lab notebook
QUIZ — MODULE 4
When measuring voltage with a multimeter, how should the probes be connected to the circuit?
MODULE 05 · WEEKS 9–10
Project A: Solar Emergency Lamp
BUILD · WIRE · TEST · PACKAGE
5.1 System Overview
SOLAR PANEL
5V / 1W
→
TP4056
Charge module
→
3.7V BATTERY
2000mAh LiPo
→
SWITCH
ON / OFF
→
LED BOARD
Parallel array
5.2 Circuit Diagram
SOLAR LAMP — COMPLETE CIRCUIT DIAGRAM
The animated LEDs show the parallel arrangement. In parallel, if one LED fails, the rest continue glowing. The blocking diode (not shown) prevents battery discharge back into the solar panel at night. Always test with a multimeter before sealing the enclosure.
5.3 Construction Steps
1
Connect the solar panel to TP4056 IN+ and IN−
Check polarity! Red wire = IN+, Black wire = IN−. Use heat shrink on all solder joints. Test: cover panel — measure IN voltage should be 0V. Uncover — measure ~5V.
2
Connect the LiPo battery to TP4056 B+ and B−
Connect battery. Red LED should illuminate (charging). Check battery voltage: it should be between 3.0V and 4.2V. NEVER connect with reversed polarity — this instantly destroys the module.
3
Wire the switch between battery positive and LED board
Cut the positive wire from battery to LED board. Insert the switch inline. Test: switch ON → LED lights. Switch OFF → LED off. Secure all joints.
4
Arrange LEDs in parallel on the LED board
All LED positive terminals connect to the + rail. All negative terminals connect to the − rail. Add a current-limiting resistor (150–470Ω for white LEDs at 3.7V). Connect LED board negative to battery negative.
5
Mount components in enclosure
Use glue gun to secure PCB, battery, and switch. Cut a window for the panel. Drill a hole for the switch. Ensure no bare wires can touch the enclosure or each other.
6
Test fully assembled lamp
Test in sunlight: panel charges (red LED on TP4056). Test lamp: switch on → LEDs illuminate. Measure battery voltage after 3 hours in sun. Record all results in lab notebook.
PRACTICAL OUTCOME — WEEKS 9–10
✓
Each student fabricates ONE functional solar emergency lamp that charges in sunlight and illuminates for minimum 2 hours
✓
Submit a completed lab report with circuit diagram, component list, measurements (voltage, current, brightness estimation), and reflection
✅ PROJECT A OUTCOME: Functional Solar Emergency Lamp
QUIZ — MODULE 5
In the solar lamp circuit, the LEDs are connected in parallel. What is the PRIMARY advantage of this arrangement?
MODULE 06 · WEEKS 11–12
Project B: Mini Solar Fan
DC MOTOR · PROPELLER · BATTERY · DIRECT AND BATTERY MODES
6.1 DC Motor Fundamentals
A DC (Direct Current) motor converts electrical energy into mechanical rotation. When current flows through the motor windings, it creates a magnetic field that interacts with permanent magnets inside the motor, producing torque (rotational force).
Property
Description
Solar Fan Implication
Start-up current
A DC motor draws MORE current when starting than when running
Ensure battery/panel can supply the peak start-up current (2–3× running current)
Operating voltage
Motor speed is proportional to voltage
At low solar panel output (cloudy), fan runs slowly — acceptable behaviour
Motor efficiency
Varies with load and speed
A balanced propeller runs most efficiently; imbalanced blades waste energy
Reverse polarity
Reversing + and − reverses motor direction
Double-check polarity before connecting — reversed polarity can damage motor windings
6.2 Two Operating Modes
Direct Sun Mode: The solar panel connects directly to the DC motor (with a diode for protection). The fan runs only when there is sufficient sunlight — it slows or stops in clouds and shade.
SOLAR PANEL
6V / 1W
→
DIODE
1N4007
→
SWITCH
ON/OFF
→
DC MOTOR
+ Propeller
Advantage: Simple, no battery needed. Disadvantage: Only works in sunlight.
Battery Storage Mode: Full solar charging system — the panel charges a battery during the day via a TP4056 module. The fan draws power from the battery and can run even when there's no sunlight.
SOLAR PANEL
5V
→
TP4056
Charger
→
BATTERY
3.7V
→
SWITCH
ON/OFF
→
DC MOTOR
+ Propeller
Advantage: Runs day and night. Better for real-world use. Our students will build this version.
6.3 Blade Balancing
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An unbalanced propeller vibrates excessively, wasting energy, creating noise, and reducing motor life. To balance: attach propeller to motor shaft and spin slowly — observe which blade dips down (heavier side). Sand the heavy blade slightly on the back surface. Re-test until the propeller hovers balanced at any position.
✅ PROJECT B OUTCOME: Portable Solar Mini Fan (battery storage mode)
QUIZ — MODULE 6
A solar fan in "direct sun mode" stops spinning when a cloud passes over the panel. How would you redesign the system to make the fan run even when clouds reduce panel output?
The boost converter is the key difference from the lamp and fan projects. A phone requires 5V USB output, but our 18650 battery only provides 3.7V. The boost converter steps the voltage UP from 3.7V to a stable 5V output — this is how all commercial power banks work.
7.2 The BMS (Battery Management System)
BMS PROTECTION FUNCTIONS
The BMS board connects between the raw 18650 cell and the boost converter output. NEVER omit the BMS — a lithium battery without protection can overheat and cause a fire or explosion if overcharged, short-circuited, or deeply discharged.
7.3 Assembly Steps
1
Solder the 18650 cell holder
Use a spring-loaded cell holder. Solder red wire to + terminal, black wire to − terminal. Measure cell voltage with multimeter before connecting anything else (should be 3.0–4.2V).
2
Connect cell to TP4056 B+ and B−
This allows the solar panel to charge the 18650 cell safely. The TP4056 limits charge voltage to 4.2V and charge current to 1A. Red LED = charging in progress.
3
Connect cell (via BMS) to boost converter input
The BMS B+ and B− connect to the cell. The BMS output (P+ and P−) connects to the boost converter input. The BMS sits between the cell and all outputs, providing all four protections.
4
Connect boost converter output to USB module
The boost converter output is 5V. Connect to the USB port module (+5V and GND). Use a multimeter to confirm 5V output before connecting any phone — incorrect voltage can damage the phone's charging circuit.
5
Connect solar panel to TP4056 IN+ and IN−
The 5V solar panel connects to the TP4056 input. In sunlight, the panel charges the battery. The USB output can simultaneously deliver power to a phone (the TP4056 handles pass-through charging).
6
Mount in enclosure; conduct phone charging test
Secure all components with hot glue. Mount panel on top. Label: input/output ports, capacity, student name. Plug in a real phone and confirm it charges. Record milliamp delivered over 30 minutes.
✅ PROJECT C OUTCOME: Working Solar Power Bank — Phone Charging Test Confirmed
QUIZ — MODULE 7
Why is a boost converter necessary in the solar power bank circuit?
Short circuit; too much current; inadequate heat dissipation
Touch-test components (carefully!); measure current draw
Disconnect power; find and fix short; add heatsink
Loose joint (intermittent)
Cold solder joint; physical stress on wire
Wiggle wires; observe if circuit flickers; test continuity
Reheat joint with fresh solder; strain-relieve wire
Battery drains rapidly
Battery degraded; excessive load; self-discharge
Measure battery capacity with discharge test; check load current
Replace battery; reduce LED count; check for leakage current
8.2 Testing Protocols
✅ Complete Testing Checklist Before Product Submission
Open-circuit voltage (Voc): Measure panel voltage with nothing connected — should match rated voltage (±10%)
Load voltage (Vload): Measure voltage across LED/motor with circuit running — voltage drops slightly under load
Charging current: Use ammeter in series between panel and TP4056 — should be 0.3–1A in full sun
Battery health: Charge battery fully; then discharge through a known load; measure time — compare with rated capacity
USB output voltage: For power bank — must be 4.9–5.1V under load; use a phone with USB voltage display app
Runtime test: Charge fully; switch on lamp/fan; record time until output fails — compare with calculated estimate
8.3 Product Design and Entrepreneurship
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Packaging
Professional packaging increases perceived value and protects components
Use PVC enclosures, acrylic boxes, or repurposed plastic containers. Seal all seams with waterproof silicone. Label the product with: product name, voltage/capacity specs, your brand, "Made in Nigeria" label. A well-packaged ₦2,000 lamp can sell for ₦5,000.
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Branding
Create your own solar brand identity
Design a logo using free tools like Canva. Print labels on adhesive paper. Include: brand name, product specs, warranty statement ("30 day replacement"), your contact number. A strong brand differentiates your product in a crowded market.
Students in hostels without steady power. Rural households. Roadside vendors. Market traders (solar insect killers). Small churches and mosques. Health centres. Start with your school community — offer a maintenance warranty to build trust. Scale to communities within 30km. Partner with NGOs for bulk orders.
8.4 Entrepreneurship Product Ideas
Product
Components Needed
Market Price Range
Difficulty
Solar reading lamp
Panel + LiPo + TP4056 + LEDs + switch
₦5,000 – ₦10,000
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Solar phone charger
Panel + 18650 + TP4056 + BMS + boost + USB
₦6,000 – ₦12,000
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Rechargeable lantern
Panel + lead-acid + PWM + LED bar
₦8,000 – ₦15,000
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Solar insect killer
Panel + battery + UV LED + mesh enclosure
₦4,000 – ₦8,000
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Solar garden light
Panel + NiMH + solar charge IC + LED
₦2,500 – ₦5,000
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Solar mini radio charger
Panel + battery + boost + audio amp
₦10,000 – ₦20,000
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QUIZ — MODULE 8
A student's solar lamp shows intermittent flickering — it works when held in one position but flickers when moved. What is the MOST LIKELY cause?
COURSE COMPLETE ☀️
You Are Now a Solar Maker
You can design, build, test, and troubleshoot solar-powered devices. You have the skills to start a solar gadget business. The sun rises every day in Nigeria — your sunlight factory is open 365 days a year. 🌞🔋⚙️
✅ Solar Emergency Lamp Built✅ Solar Mini Fan Built✅ Solar Power Bank Built