Solar Panel Connection II SS1 Solar Photovoltaic Installation & Maintenance Lesson Note

What is a Parallel Connection?

Think of a Parallel connection as a “Team” setup. Instead of joining panels one after the other like a chain (Series), you connect all the Positive (+) wires together and all the Negative (-) wires together.

• The Rule: Positive to Positive, Negative to Negative.
• The Result: You have one big “Super-Positive” junction and one big “Super-Negative” junction.

In Nigeria, we use this when we need to “fatten” our power. If you want to charge your batteries faster or run heavier loads during the day, you usually need more “flow,” and that’s what parallel gives you.

The Current Effect (The “Flow” Rule)

The most important thing to remember about a parallel connection is that Current (Amps) adds up.

If you have two panels, and each one gives 8 Amps:

• Panel 1 (8A) + Panel 2 (8A) = 16 Amps.

If you add a third 8A panel:

• 8A + 8A + 8A = 24 Amps.

What about the Voltage (Pressure)? In a parallel connection, the voltage stays the same. If each panel is 18V, the whole group is still just 18V. You haven’t increased the “pressure,” you have only increased the “volume” of electricity moving through the wires.

The “Branch” Benefit (Shade Resistance)

One of the best things about parallel connections is that each panel works independently.

Remember in Series, if a bird poops on one panel, the whole chain suffers? In Parallel, that doesn’t happen.

• The Analogy: Think of several people pumping water into a large tank using separate pipes. If one person stops to rest (shade), the other people are still pumping water into the tank at full speed.
• In Real Life: If you live in a place with many trees or “overhanging” roofs, a parallel setup is much safer because a shadow on one panel won’t “kill” the production of the others.

When do we use Parallel Connections?

We use parallel connections mostly for smaller systems or when using certain types of equipment:

1. PWM Charge Controllers: Most basic (PWM) controllers cannot handle high voltage. If you have a 12V battery, you connect your panels in parallel so the voltage stays low enough for the controller to handle.
2. Faster Charging: If your batteries are taking too long to charge during the day, adding another panel in parallel increases the “Amps” going into the battery, filling it up faster.
3. Low Voltage Systems: If you are running 12V DC bulbs or fans directly, you need to keep your panels at a 12V rating. Parallel allows you to add 10 panels while keeping the system at 12V.

The Warning: Because the “Current” (Amps) is high, you must use thicker wires. Thin wires will get very hot and could cause a fire if they are carrying too many Amps.

Summary and Comparison Table

Quick Revision: Series vs. Parallel

Class Discussion Questions

1. If you have two 12V, 5A panels and you connect them in parallel, what is the final Voltage and Amps?
2. Why is it “safer” to have a tree shadow on a parallel system than on a series system?
3. Case Study: Mr. Okon bought 4 panels for his shop. He used very thin wires to connect them in parallel. Why did he start smelling “burnt plastic” after two hours of bright sunlight?