PV System Maintenance I – SS2 Solar Photovoltaic Installation & Maintenance Lesson Note (Second Term)

Preventive maintenance means fixing small things before they become big, expensive problems. For a solar PV system, it includes cleaning panels the right way, checking terminals for loose wires and corrosion, clearing dust from the inverter and controller, and recording each job in a logbook. In Nigeria, dust and heat are the two major efficiency killers.

Behavioural objectives

By the end of the lesson, students should be able to:

1. Explain what preventive maintenance is and why a PV system needs it.
2. State the rules for cleaning solar panels safely.
3. Check wire and battery terminals for looseness, overheating and corrosion.
4. Describe how to examine the inverter and controller.
5. State what should be recorded in a maintenance logbook.

Why does a PV system need maintenance?

Some people think that because solar panels have no moving parts, they never need attention. This is a mistake. In Nigeria, we have two major “efficiency killers”: dust and heat.

Preventive maintenance means fixing small things before they become big, expensive problems.

If you do not maintain a system:

1. Dust can reduce power by 30% or more.
2. Loose wires can cause “arcing” (sparks), which can lead to fires.
3. Corrosion (rust) on battery terminals stops the battery from charging fully.

How do you clean solar panels the right way?

Cleaning is the most common maintenance task. If it is done wrongly, you can crack the glass or damage the cells inside.

The golden rules of cleaning

• Time of day: Only clean panels in the early morning or late evening. If you pour cold water on a hot panel at 1:00 PM, the glass can shatter from “thermal shock”.
• No soap: Usually, plain water is best. Harsh detergents can leave a “film” or streak that blocks the sun.
• Soft tools: Use a soft brush or a microfibre cloth. Never use a wire brush or anything abrasive that will scratch the glass.

How do you check terminals (the “shake” test)?

In an electrical system, the “terminal” is where a wire connects to a component, such as a battery or an inverter. Over time, vibrations and temperature changes can make these connections loose.

Steps for checking terminals

1. The physical check: With the power off, gently “wiggle” the wires. If they move even a little, the bolt needs tightening.
2. Look for discoloration: If the plastic around a wire looks melted or brown, the connection was loose and getting very hot. You must cut the wire and reconnect it properly.
3. Battery terminals: Look for white or blue “crusty” powder on battery tops. This is corrosion. Clean it off with a stiff brush and apply a little petroleum jelly (Vaseline) to stop it from coming back.

How do you examine the inverter and controller?

The “brain” of the system also needs a checkup. These devices have fans to keep them cool, so they act like vacuum cleaners and suck in dust and lint.

Maintenance steps

• Air vents: Use a dry brush or a “blower” to clear dust from the inverter’s air vents. If the vents are blocked, the inverter will overheat and shut down.
• The “ear” test: Listen to the fans. If they make a grinding or loud squeaking noise, the fan is about to fail and should be replaced.
• Screen check: Look at the screen for “error codes”. Sometimes a system is working but has a warning light that tells you something is wrong with the earth connection or the grid.

Why keep a maintenance logbook?

A professional technician always keeps a logbook. This is a small notebook kept near the inverter where you record what you did.

What to record

1. The date: When was the last cleaning?
2. The reading: What was the “peak watts” produced at noon? If this number gets lower every month even when the sun is bright, you have a problem.
3. Actions taken: For example, “Tightened battery terminals” or “Cleared bird nest from under panels”.

How do your senses help with maintenance?

Maintenance includes more than cleaning. It depends on observation. Use your eyes to look for cracks, your ears to listen for unusual noises, and your nose to smell for burning plastic.

Evaluation

1. What is preventive maintenance?
2. Why should solar panels be cleaned only in the early morning or late evening?
3. Give two signs that a wire connection is loose or has been overheating.
4. How do you deal with corrosion on a battery terminal?
5. State three things that should be recorded in a maintenance logbook.

Assignment

List three problems that can result from poor PV system maintenance. Then write a short checklist of the tasks a technician should carry out on the inverter and controller.