Solar Panel Connection & Its Types SS1 Solar Photovoltaic Installation & Maintenance Lesson Note

Why Connect Panels Together?

Imagine you want to power a big “I-pass-my-neighbor” pumping machine, but you only have one small solar panel. One panel is like one person trying to lift a heavy bag of cement—it might be too weak.

To get more power, we have to make the panels “work as a team.” There are two main ways to connect them:

1. Series Connection (Joining them like a chain).
2. Parallel Connection (Joining them side-by-side).

Today, we are focusing on the Series Connection and how it changes the “pressure” (Voltage) of our system.

How to Connect in Series

Connecting in series is like a “handshake.” You connect the Positive (+) terminal of the first panel to the Negative (-) terminal of the second panel.

• The Rule: Positive to Negative.
• The Result: You are left with one free Positive wire at one end and one free Negative wire at the other end to go into your charge controller.

Think of it like a relay race where one runner hands the baton to the next. The electricity flows through the first panel, then straight through the second, then the third, and so on.

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The Voltage Effect (The “Addition” Rule)

The most important thing to remember about a series connection is that Voltage adds up.

If you have two panels, and each one is rated at 12 Volts:

• Panel 1 (12V) + Panel 2 (12V) = 24 Volts.

If you add a third 12V panel:

• 12V + 12V + 12V = 36 Volts.

What about the Current (Amps)? In a series connection, the current stays the same. If each panel gives 5 Amps, the whole chain still only gives 5 Amps. The “flow” doesn’t increase, only the “pressure” (Voltage) increases.

When do we use Series Connections?

In Nigeria, we mostly use series connections when we have a long distance between the roof and the battery room.

1. To Match the Controller: If you have a 24V battery bank, your panels must produce more than 24V to charge them. Connecting two 12V panels in series gives you the 24V you need.
2. To Save Money on Wires: High voltage can travel through thinner wires without getting too hot. By increasing the voltage, we can use cheaper cables for long distances.
3. For MPPT Controllers: Modern “Smart” controllers (MPPT) love high voltage. They take that high pressure and “transform” it into more charging power for your batteries.

The “Shadow” Danger (The Weakest Link)

There is one big problem with connecting panels in series. Because they are in a chain, the whole system is only as strong as the weakest panel.

• The Analogy: Imagine a water pipe. If you put a small stone in one part of the pipe, the water slows down for the whole pipe.
• The Reality: If you have 4 panels in series and a tree casts a shadow on just one panel, the power of the entire chain drops significantly.

Summary Table

Class Quiz

1. If you connect four 18V panels in series, what is the total voltage?
2. You have a 12V panel that produces 8 Amps. If you connect two of them in series, what is the new Voltage and the new Amps?
3. Why should you make sure no “overhanging” tree branches are near a series-connected solar array?