A Detailed Guide To Solar Panel Wiring - The How's And The Why's

A Detailed Guide To Solar Panel Wiring – The How’s and The Why’s

Solar Panels Wired in Series and Parallel

As a homeowner who has learned about solar panels and solar energy options, it is pretty easy to get confused with the technical terms you have heard about Solar Energy. For example, you may have heard about wire solar panels to utilize solar power. 

Connecting more solar panels is an effective way to boost your home’s solar power capabilities, and you can quickly go eco-friendly and sustainable by implementing Solar Panels.

However, solar panels are quite expensive in today’s world. The panels do cost higher; pairing them also adds an extra labor cost. On the other hand, the wiring process[1] of solar panels is also quite tedious and confusing at times, to say the least. You can’t follow a standard wiring method to connect two solar panels. Remember that your solar system requires particular types of wiring. 

How are solar PV panels wired together? And why does it matter? Do they affect the solar system’s power output level? The answer is yes; they do affect the solar output level. Besides, it also affects the performance of the string inverter. You should always make sure that the panels are appropriately wired by a professional solar installer so that you can enjoy more savings. 

Connecting multiple solar panels may feel like a daunting task when looking at how the wiring is done for the first time. But with a bit of knowledge, you can make the process easier and doable. So, keep reading this article, and you will explore more about wiring solar panel systems. Besides, you will also decide whether to wire the solar panels in parallel or solar panels in a series connection. To understand this in a better manner, keep reading below.

Electrical Terms Associated with Solar Panels

Before exploring and understanding the rules to wire solar panels, it is essential to know some of the crucial electrical terms that are used in solar panel wiring. The electrical terms are: 

#1 Voltage (V)

The voltage that is measured in volts is the difference in the electrical charge between a circuit’s two-point. Besides, it makes the electricity flow. In the case of a solar array, the total output voltage can be affected by different factors. 

The most crucial factor is the irradiance of sunlight the solar array receives. It is widespread to assume that the more sunlight on the solar array, the more voltage the solar system will produce. 

On the other hand, the outside temperature can also influence the voltage. When the temperature goes up, it lowers the total energy a solar panel generates. As per the experts, on a sunny day, the solar array’s voltage will be higher than on a typical day.

#2 Electrical Current (I)

Speaking about electric current, it is the rate at which the solar charge flows. The power ratings of solar panels are evaluated based on this. In general, the electrical current is generally measured in amperes or amps. 

#3 Electrical Power (W)

Power transfer is the rate at which the solar energy is consumed or transferred from the sun to the panel. It’s measured in W or watts. In solar systems, a crucial function of the power inverter is to enhance the total power output of the solar array by varying voltage and current. As a result, you will enjoy maximum input current from the system. It may be noted that a power inverter also converts the DC energy to AC power. 

Understanding The Concept Of Wiring Of Solar Panels

To attain a well-functional solar PV output circuit, simply installing solar panels will not be enough for you. You need to make sure that all the solar panels are connected adequately so that the produced current can flow properly. 

Besides, you also need to ensure that you are using a powerful inverter to convert the DC power (produced by solar panels) into AC power. Different types of solar panel cables can be used to establish the connection, and in the solar industry, it is called stringing. Now, talking about wiring options for solar panels, you can have two options. These are series and parallel connections. Let’s talk about these connection types in detail. 

Parallel Stringing Vs Series Stringing

Even though you can go for these wiring options, different wiring options to connect solar panels will create different effects on the voltage and current in the circuit. 

Wiring Solar Panel In Parallel

Wiring the solar panels in a parallel connection means connecting the panel’s negative and positive terminals. In general, in the case of parallel solar panels, they are connected to an advanced charge controller, or sometimes they are connected to a solar inverter of the system. 

A combiner box will be located below the solar panels where the positive and negative terminals are connected to the positive connector and negative connector, respectively. In this connection type, the total will remain the same. However, the amperage will increase. 

You may note that when the panels are connected in a parallel setting, they share the same amount of voltage. The current that every panel produces is combined. 

One of the significant benefits of this wiring configuration is higher reliability. Wondering how? If there are six solar panels and one panel fails to work for some reason, this will not affect the performance of the other five panels. 

Every panel’s negative terminal is connected to its positive terminal; it creates a unique wiring connection that makes all the solar panels work independently. 

However, there are some disadvantages of such a connection that you should consider. The lower amount of voltages will denote increased current values. That means the electrical losses will be more. As a result, you will witness a lower performance from your solar panel systems.

On the other hand, increasing the amount of current will not be a good option for you. Why? It will increase wire gauges to have an excellent capacity to handle better ampere values.

Well, it may sound attractive, but for this, you will have to deal with more installation costs as you will use more giant size cables. Besides, as the cables’ length increases, the overall performance will also decrease. 

When Should You Opt For Parallel Connection

Well, the answer will vary. The total output power of the system connected in a parallel connection will be below. You may assume that the system is small and can supply lower loads. 

As per the experts, this type of wiring is generally used for 12v systems with more than two panels, as this wiring will allow you to have 12v charging capabilities. 

Wiring Solar Panels In Series Connection

Speaking about the series connections, this type of connection is done by wiring all the negative terminals for the next solar panel to all the positive terminals of another panel. Follow this structure to connect all the solar panels. 

Under such a type of connection, the voltages produced by the solar panels are combined, and the current output level is maintained at the same level for every panel. The solar panel set that is connected in series is called a string. 

Remember that higher voltages suggest lower currents, and lower voltages suggest higher currents. It is an important fact that you should always keep in mind if you think of a series connection.

As this type of wiring configuration will increase the voltage value when you use more solar panels together, the overall current capacity generated by the system will go down. 

Due to lower cable length and wire sizes, you will save money with this type of connection. Besides, it can improve the efficiency of the entire string. 

Like the series connection, the parallel connection also has some disadvantages. Series connections will lead to lower reliability. Here, the entire panels are connected using a single cable and so, if the cable fails or gets damaged, the entire solar system will stop functioning. 

On the other hand, when clouds or trees shade a solar panel in the system, this will affect the entire system’s performance, and the system voltage will go down. That’s why solar panels are ineffective during the rainy and winter seasons. 

Remember that shading is a massive issue in this wiring configuration. The primary reason is that a shaded solar panel will block the current flow. This type of effect on solar panels creates hotspots. Hotspots are sections with higher temperatures, and based on your solar system size, solar panels size, and wiring; they can create different security issues. 

The Best Condition To Use Series Wiring Configurations

In general, when you need to produce more voltage, you will need more solar panels. But another thing to consider here is the type of wiring you have selected for connecting solar panels. 

The experts have suggested that connecting solar panels in series will be a perfect option for more voltage. 

On the other hand, when the distance between the charge controller, inverter, and solar panels exceeds 20 feet, you should opt for a series connection. The solar panels connected in series will allow you to get more voltage from the system and effectively meet the inverter’s voltage input level. 

The series wiring connection has its issues, as described in the above sections. But if you want to give this option a try and are concerned about the efficiency and or shading issues, then here are some tips that you can follow. 

Using an inverter for each panel will make the panel independent from each other. Once done, the shading of panels will not affect the system’s overall power capacity. 

The other solution, is that you can buy similar solar panels or bypass diodes. The diodes will function as a wall and isolate or block the shaded areas to eliminate efficiency losses of the other panels. As a result, the output power level of the system will not go down. 

With issues related to the system’s efficiency. As per the experts, while connecting solar panels in series, you can use micro-inverters for every panel to make them function at their maximum efficiency level. 

However, you can’t solve the issues related to reliability as it is the most common feature of the solar panel’s connection. 

Understanding the Parallel-Series Connections

After going through the above sections, you can know the disadvantages and advantages of parallel and series wiring for connecting solar panels. 

Choosing a perfect connection type is essential based on the current’s input capacity and the voltage capacity of a charge controller, and the inverter used in the solar panel. 

However, it has been seen that in some cases, you will not be able to attain the required current and voltage range by implementing a parallel or series wire connection. 

In the case of parallel solar panels, the current limit can be increased. On the other hand, you can increase the voltage limit of solar panels connected in a series connection. This is done by not producing the maximum active power of the wiring configuration. 

In addition to this, You can combine these two types of connections to achieve the desired results. The idea is to build the strings by connecting multiple panels and make sure that the panels are attached through a parallel connection with the other strings. 

This way, you can enjoy the maximum advantages of the series connection, for example, lower costs and reduced electrical losses. Besides, you will also be able to enjoy a parallel connection’s benefit, i.e., an excellent level of reliability. 

In simple words, each string of multiple panels will contribute to the current and work independently from other strings’ performance. And at the same time, you will witness an increased active power with lower current values and higher voltage. 

Remember that creativity plays a significant role in this type of wiring configuration. How? You can develop different design ideas using the same number of solar panels using your creativity. And you can customize the design to meet your home’s monthly electricity consumption level. 

How Do Solar Panels Circuit In Series Compared To Panel Wired In Parallel Connection? 

A better charger controller can be a determining factor in choosing the right solar panel wiring. MPPT- Maximum Power Point Tracking charge controllers are perfect for wiring solar panels in series. On the other hand, the PWM- Pulse Width Modulation charge controller is widely used for wiring multiple solar panels in a parallel circuit. 

To properly understand how the wiring in solar panels in parallel works in comparison to how connecting solar panels in series works, let’s consider an example of how Christmas lights work. 

The whole string will not light up when a bulb comes loose from the socket, breaks, or is burned out. The reason behind this is the light bulbs were connected in a series connection. To make it work again, you need to find out the faulty bulb and replace that with a new one. 

However, now most of the lights come with a parallel wiring connection, which enables the light strings to keep functioning even if one light bulb isn’t working. 

Circuits that are  wired in the series function similarly for the solar panel’s systems. If one solar panel connected in a series is not working, the entire setup will fail. However, the defective solar panel installed in a parallel connection will not affect the putout of other working panels. 

Is It Possible To Add More Panels To Your Existing Solar Systems?

Well, installing a complete solar panel system from the beginning which meets all your energy requirements is always the best option when installing your residential solar system. 

Using a professional solar energy calculator, you can estimate the total costs of the systems and how many panels you will need to meet your required voltage ratings. This is an essential task before buying solar panels. 

However, if you miscalculate your future power requirements, you can always add more panels to your system to increase the power output level. So don’t worry about getting your calculations wrong; you can fix it later. 

If you plan to expand your PV panels system in the coming years, you need to design the solar power system by keeping that in mind. On the other hand, use a large inverter to prevent any possible issues. 

Combining Multiple Solar Panels With Different Characteristics

It is also crucial to consider when choosing the connection type for your solar power system. You should always consider the electrical characteristics of the solar panels you use or want to use. 

Just image, you are using parallel strings for the solar system, and the system has a set of similar solar panels. The panels have the same characteristics of electrical efficiency and are made by the same manufacturer. Now you want to add different solar panels. 

Well, before doing that, you should consider the basic rule. Panels connected in a parallel connection produce the same level of voltage. On the other hand, in a series connection, you will get the same current level. 

So, when you connect different panels, that will affect the output level and damage your system. That’s why it is not advisable to use solar panels with different characteristics together, as you may encounter issues like low performance. 

However, always keep in mind that the important decision-makers to create a connection type should have are: 

• Total distance between the panels and inverter. 

• Specifications of inverter and charge controller

• Size of the solar system 

• Projected power generation level 

The selection of solar panel connections will depend on the deep technical analysis. So, taking the help of a professional solar installer can be a good idea. 

Conclusion

Connecting multiple solar panels to attain higher voltage is not that complicated. How many parral strings of solar panels you want to create per array will depend on the amount of voltage you want to produce. 

For example, if you aim for a 10 to 15-volt battery charging unit, then wiring solar panels in parallel will work great. However, suppose you are aiming for a higher voltage system. In that case, it will be better for you to go for the solar panels in series wiring option, or you can combine both the parallel and series wiring of Pv panels for maximum power point rate. 

Well, for an easy reference for how to connect a solar panel in either series or parallel wiring configurations, just keep in mind that series wiring means moe voltage, and parallel wiring means more amperes. 

Both the amperage and voltage need to be considered while designing your solar system, especially when looking for a solar inverter that will allow you to use maximum voltage. 

Connect solar panels with the right type of wiring options, and you will be able to power up any electrical devices in your house. It has been seen that most of the time, an experienced solar installer will suggest you wire more solar panels in series as well as parallel collections to get higher amps and system voltage.

Understand your system voltage requirements and the maximum power you need per day, and consult a solar installer to know which wiring options will work best for you. 

FAQs

Is It Better To Wire Solar Panels In Parallel Or Series? 

When connecting different solar panels or two solar panels into an off-grid system, homeowners will get a few options. These are parallel wiring solar panels, series wiring solar panels, or combined. 

However, theoretically, solar panels in parallel wiring can be a good option for different voltage ratings and multiple electrical characteristics. How? This type of solar panels wiring will facilitate continuous operations of the solar power system, even though one of the solar panels is not working correctly. 

However, this may not work effectively for wiring solar panels in every situation. The same way of connecting solar panels might not work. Sometimes, you may need to meet the desired voltage requirements to keep your solar inverter operating correctly. 

On the other hand, a perfect balance of amperage and total output voltage needs to be attained so that the solar arrays can perform at their best. So, most solar installers suggest that you go for hybrid wiring solar panels that combine parallel and series connections. 

If you don’t know much about how to wire solar panels in series connections or solar panels in parallel collections, you should always take the help of an expert installer. 

Do You Need Any Special Type of Wire For Solar Panels?

The experts say you can’t use a standard wire for wiring solar panels with a solar power system. As you all know, most solar power systems installations are done outdoors in harsher conditions. The wiring for connecting solar panels has to perfectly meet the moisture, UV resistance, and heat standards. 

When it comes to enjoying perfect solar panel wiring, you should always go for USE-2 wire or PV wire for your solar PV system. Panel connected through these wires can transfer maximum power. As these wires have the utmost capacity of power transfer through the system. 

PV wire is created for interconnecting multiple PV modules and can also be used under a parallel configuration. This wire can easily withstand a temperature of 105-degree C in dry conditions and around 90-degree C under wet conditions. The power rating and voltage rating of this wire are also good. 

On the other hand, USE-2 wire is widely used for series connections, and you can connect different terminals of service devices. In general, you can find this type of wire underground. It can work perfectly at 105-degree C in dry and 90-degree C in wet conditions. Solar panels connected using this wire can demonstrate maximum PowerPoint. Based on your existing system’s requirements, conditions, and power rating, you can go for PV or USE-2 wire. 

What Is The Best Way For Wiring Solar Panels?

The best way to wire or connect solar panels will depend on the application. For example, connecting solar panels in series will be a good option if you plan to use your solar system in an unshaded location. 

The primary reason is that solar photovoltaic panels will perform much more efficiently and better at the beginning and end of the day. Besides, you will also get solar power when it is cloudy. 

How To Wire Solar Panels To The Breaker Box? 

Suppose you don’t know much about a breaker box. In that case, it is also called an electrical circuit breaker panel—the breaker box located in your house functions as the central distribution point for all the electrical circuits. You can connect the solar batteries to this to run some solar power devices. 

However, before using solar power, you need to convert the direct current created by solar panels into alternating current that your home appliances will you. For this, you will need a power inverter. And you can then connect the power inverter to the AC fuse box. Always follow the basic principles while doing this to avoid any issues. Always use a relevant charge controller and inverter for better voltage. 

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