How to Wire Solar Panels in Series-Parallel Configuration?

How to Wire Solar Panels in Series-Parallel Configuration? . Solar energy is one of the most sustainable and cost-effective energy solutions. However, the efficiency of a solar system largely depends on how the solar panels are wired. Proper wiring ensures maximum energy output and compatibility with the system’s inverter and battery. This guide focuses on how to wire solar panels in series-parallel configuration, a method that balances voltage and current for optimized performance.

Understanding Series Wiring for Solar Panels

What is Series Wiring?

In series wiring, the positive terminal of one panel connects to the negative terminal of the next. This setup increases the total voltage while maintaining the same current as a single panel.

Read More : How to Wire Lights in Series?

Advantages of Series Wiring

• Higher Voltage Output: Ideal for systems requiring high voltage to operate efficiently.
• Reduced Energy Loss: Minimizes losses during transmission over long distances.

Series-Parallel Connection of Solar Panels to the Battery and Inverter

For small residential loads, using a series-parallel combination of solar panels is less common but still a possible wiring configuration. This setup connects the solar panels to batteries, AC and DC loads through a charge controller, battery, and UPS/inverter. Depending on the system requirements and design, solar panels and batteries can be connected in series, parallel, or a more complex series-parallel configuration to meet specific needs.

In this tutorial, we will explain the basic wiring of photovoltaic panels in a series-parallel configuration. This includes connecting them to one or more batteries, a charge controller, and both AC and DC loads via the charge controller or an inverter.

Read More : Series and Parallel Connection of Batteries

This arrangement is needed when we want to double the level of voltage (voltage is additive and current is same in series connection) as well as the charging current (current is additive and voltage is same in parallel connection) from solar panel to the batteries and other load points. In this case, we will have to connect multiple solar panels (photovoltaic array) in series parallel connection to the batteries and load points.

By connecting the photovoltaic panels in series-parallel configuration, we get benefits of both connections i.e. doubling the level of voltage and increasing the current rating from solar panels to the batteries and AC/DC load.

Read More : How to Wire Batteries in Series to a Solar Panel and UPS?

Voltage and Current in Series-Parallel Connected Solar Panels

Suppose we have 12V, 10A ,120W solar panels connected in series-parallel connection.

A set of two solar panels connected in series

Series Voltage:

V₁ + V₂ ….. + V_n

12V + 12V = 24V.     …     (Voltage is additive in series connection)

Series Current:

I₁ = I₂ ….. = I_n

10A = 10A = 10Ah     …     (Current is same in series connection).

Now, we have two sets of series connected solar panels. If we connect these two set in parallel:

Parallel Voltage:

V₁ = V₂ ….. = V_n

24V = 24V = 24V     …     (Voltage is same in parallel connection

Parallel Current:

I₁ + I₂ ….. + I_n

10A + 10A = 20A     …     (Current is additive in parallel connection).

Read More : How to Wire Switches in Series?

Finally, we get 24V, 20A from four PV panels each of 12V and 10A i.e. we doubled both the voltage and current capacity of solar panels e.g. voltage from 12V to 24V and amperage from 10Ah to 200Ah by connecting PV panels in series-parallel configuration.

Wiring Photovoltaic Panels in Series-Parallel Connection

To do this wiring, make two sets (pairs) of PV panels and connect them in series. This way, you will have two pairs of solar panels connected in series. Now, connect the two sets of series connected solar panels in parallel as shown in the following fig.  Now, you are having four 12V, 10A solar panels connected in series-parallel configuration.

As a next step, you can connect these solar panels to a charge controller. A basic DC load (12 or 24V) can be directly powered up by connecting it to the charge controller.

The AC load can be powered up in two ways. Firstly, it can be directly powered up by solar power during the normal sunshine (day). Secondly, the AC load (120V/230V AC) can be powered up by the stored power in the batteries using an inverter during shading (or night). Keep in mind that the number of solar panels and batteries depends on the load requirements where solar panels keep charging the batteries as well as power up the AC load.

Read More : Why Does the High-Wattage Bulb Glow Dimmer in a Series Circuit?

The following solar panel and battery wiring diagram shows how to wire a four 12V Solar Panels in series-parallel connection to a 24V, 400Ah battery with an automatic inverter system. Note that the number of solar panels and batteries depends on the system’s design and load requirements i.e. multiple batteries and solar panels can be connected in series, parallel or series parallel connection to increase the Ah rating and storage capacity. (we have discussed them in previous post).

This wiring is fully automatic due to auto UPS wiring i.e. no need to install an auto or manual changeover / ATS switch to change between the solar power or battery storage power to the load points.

Read More : Parallel vs. Series Circuits Understanding the Difference with a Practical Example

Good to know:

• Current is additive while voltage is the same in parallel connection.
• Current is the same while voltage is additive in series connection.
• Only the same rated solar panel can be connected in series, parallel or series parallel connection.
• A 12V solar panel can only be connected in (series, parallel or series-parallel) with another 12V solar panel.
• A 12V solar panel should not be connected (in series, parallel or series parallel) to a 6V or 24V solar panel.

Step-by-Step Guide to Wiring Solar Panels in Series-Parallel

Tools and Equipment Required

• Multimeter
• Solar cables
• MC4 connectors
• Wire cutters
• Safety gloves

Safety Precautions to Take

• Wear insulated gloves to prevent electric shocks.
• Work in dry conditions to avoid electrical hazards.
• Turn off all connected equipment before starting.

Read More : The Complete Guide to basic electrical engineering pdf

Wiring Solar Panels in Series-Parallel: A Step-by-Step Process

1. Group Panels: Divide panels into smaller series groups.
2. Connect in Series: Link panels in each group using the series wiring method.
3. Connect Groups in Parallel: Use branch connectors to link the positive terminals of all groups together and the negatives similarly.
4. Test the System: Measure the total voltage and current to ensure proper configuration.

Common Mistakes to Avoid When Wiring Solar Panels

Overlooking Voltage and Current Requirements : Ignoring the voltage and current specifications of your inverter or battery can lead to system inefficiency or damage.

Incorrect Connections : Crossing positive and negative wires can cause short circuits. Double-check connections before activating the system.

Applications of Series-Parallel Solar Panel Wiring

Off-Grid Systems : Perfect for standalone setups that require high power output and battery charging capabilities.

Hybrid Solar Systems : Used in residential and commercial systems to balance grid-tied and battery backup functionalities.

Read More : Clamper Circuit – Types, Working, and Applications Explained

FAQs on Wiring Solar Panels in Series-Parallel Configuration

What is the difference between series and parallel wiring?
Series increases voltage, while parallel increases current.

Why use a series-parallel configuration?
It balances voltage and current for efficient energy use.

What tools are needed for solar panel wiring?
Essential tools include a multimeter, MC4 connectors, and insulated gloves.

How do I ensure safe wiring of solar panels?
Follow safety guidelines, use insulated tools, and test connections before activation.

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