Comprehensive Revision II SS3 Solar Photovoltaic Installation & Maintenance Lesson Note

Class: SS3

Subject: Solar Photovoltaic Installation and Maintenance

Topic: Practical Skills, Tool Mastery, and Field Procedures

The Technician’s Tool Bag

In a practical exam, the examiner isn’t just looking for the right answer; they are watching how you handle your tools. A technician who uses a kitchen knife to strip a wire will lose marks immediately!

Must-Know Tools for the Exam:

• Digital Multimeter: Your “eyes.” You use it to check if a battery is charged or if a panel is producing power.
• Crimping Tool: Used to attach MC4 connectors to the ends of solar cables. A good crimp should be so tight that you cannot pull the wire out with your hands.
• Wire Strippers: Used to remove the plastic insulation without “wounding” the copper strands inside.
• Inclinometer (Angle Finder): Used to make sure the panels are tilted at the correct angle (usually 15 degrees for most parts of Nigeria).

Pro-Tip: Always “zero” your multimeter before testing. Check your leads for breaks before you start.

Practical Wiring – The “Series vs. Parallel” Test

You will likely be given two batteries or two panels and asked to connect them for a specific result.

The Practical Rule of Thumb:

1. To get more Voltage (Series): Connect the Positive (+) of Component A to the Negative (-) of Component B. The remaining (+) and (-) go to your controller. This is how we turn two 12V batteries into a 24V bank.
2. To get more Current/Amps (Parallel): Connect Positive (+) to Positive and Negative (-) to Negative. This keeps the voltage the same but allows the system to run for a longer time.

Common Exam Trap: If you connect a battery in series but forget to change the setting on your charge controller, you might see an “Overvoltage” error. Always check your settings!

Troubleshooting Scenarios (The Lab Test)

The examiner might “fault” a system and ask you to find the problem. Don’t panic; just follow the energy path.

Scenario 1: “The Inverter is on, but the bulb isn’t lighting up.”

• Check 1: Is the AC breaker/switch turned on?
• Check 2: Use your multimeter to check the AC output of the inverter. If the inverter shows 220V but the bulb is dark, the bulb is dead or the wire is broken.

Scenario 2: “The Charge Controller screen is blank.”

• Check 1: Is the battery connected? Most controllers won’t turn on without battery power.
• Check 2: Check the fuse between the battery and the controller. If the fuse is blown, the “brain” (controller) has no power to wake up.

Maintenance Procedures (Hands-on)

You might be asked to demonstrate how to “service” a solar installation.

Step-by-Step Service Routine:

1. Panel Cleaning: Use a soft sponge and water. Show the examiner that you are checking for “hotspots” (dark burnt spots on the cells) while cleaning.
2. Terminal Cleaning: If you see white “beards” (corrosion) on the battery heads, explain that you would clean them with warm water and a wire brush, then apply petroleum jelly.
3. Tightness Test: Use a spanner to gently check every bolt. Warning: Never tighten a “live” terminal with a metal spanner that isn’t insulated—you could cause a massive spark!

The Final Commissioning Report

In a practical exam, you are often asked to “Document your findings.” This is the last step before you “Hand over” the project.

What to write in your Practical Report:

• Voc (Voltage Open Circuit): The voltage of the panels when they aren’t connected to anything.
• Vbat (Battery Voltage): The voltage of the batteries before and after charging.
• System Polarity: Explicitly state: “Polarity was verified to ensure Positive to Positive and Negative to Negative.”
• Observations: Mention any shading issues or structural concerns with the roof.

Final Practical Tip: Always keep your workspace neat. An examiner loves a student who puts their tools back in the bag and clears away wire off-cuts. A clean site is a safe site!