Difference between serial and parallel connection of solar modules

“My roof is partly in the shade, but I would like solar panels. Is that possible?”

This is a common question we receive during telephone consultations, and the answer is always "Yes." Every solar PV system is designed to be as efficient as possible, and we account for all factors—such as roof pitch, shade, and nearby buildings—to ensure your system delivers optimal returns.

The key to addressing shading lies in choosing the right connection type for your solar panels: serial or parallel. Sometimes we recommend a serial connection, and other times, a parallel connection, depending on your roof’s specific needs. Soly will always explain our recommendation in detail so you understand why a certain setup is best for your solar PV system.

To give you a clear picture, we'll briefly discuss both connection types below and why we might choose one over the other.

What is a serial connection?

Serial connection for solar panels is the most widely used system. When solar panels are connected in series, it means that all the panels together provide the output. When serial connection is chosen, it is important that each panel gets the same amount of sunlight. As soon as one component (panel) transmits less power, it immediately has a negative effect on the overall yield. The efficiency of the system will decrease.

Serial connection for solar panels is referred to as a string because this system is connected in a circuit on the roof. Solar power flows through the circuit to the inverter, where direct current is converted into alternating current.

Keep on reading: All about Solar Inverters: How-To Selection Guide

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What is a parallel connection?

If your roof is (partly) in the shade during the day, we tend to opt for solar panels in a parallel connection. This means that each panel connects individually to the system. Each component transmits power separately. The system is thus less affected by a panel that is partially shaded. Optimisers also ensure that a panel that is (partly) in the shade will still generate sufficient solar energy. If many shadows are cast on your roof, parallel connection still ensures high yields.

How do we choose the type of connection?
Where the situation allows, we will always opt for serial connection for solar panels. This is a financially attractive system for the customer because fewer materials are required. Serial connection also delivers high(er) voltage to the system, thereby resulting in less heat loss and higher output at peak times.

Parallel connection of solar panels
On the other hand, parallel connection offers more possibilities. Even if your roof is sometimes in the shade, you can still benefit from a system that generates enough power. The system is slightly more costly because more materials are required.

Installing your solar panels

Before installing your solar panels, we will carry out a digital inspection. Thanks to the accurate data gained, we can create a unique solar panel layout plan for your home. We rely on both the information provided by you and the data coming from our systems. With that, we are confident that we can determine the right connection for your solar panels. This is all included in the solar panel offer.

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Knowledge base

While you are still here: have a look at our knowledge base. It's full of information concerning the benefits and possibilities of solar energy. And we do our bit. Here are some of the most interesting topics we already covered.

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Do you need to clean solar panels?

Over the years, the panels are exposed to numerous conditions such as rain, wind, snow, sand, and moss. Do you need to clean your solar panels every once in a while?

How much CO₂ emissions can be saved with solar panels?

Lower carbon emissions is a good reason to have solar panels installed. However, you would naturally like to know how much CO₂ you save using solar panels.

How many solar panels do I need?

We recommend choosing the minimum number of solar panels based on your annual power demand. Get to know more.

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