Mixing solar panels – Dos and Don’ts
In this article we show you:
Let’s get straight to the point.
Mixing solar panels of various voltage or wattage, or produced by different manufacturers, is a frequently asked question by most DIYers.
Though mixing different solar panels is not recommended, it’s not forbidden and things would be ok as long as each panel’s electrical parameters (voltage, wattage, amps) are carefully considered.
When you intend to wire two panels produced by different vendors, the vendors are not the problem.
The problem is in different electrical characteristics of the panels, together with different performance degradation.
We put solar panels together to increase the solar-generated power.
Connecting more than one solar panel in series, in parallel or in a mixed-mode is an effective and easy way not only to build a cost-effective solar panel system but also helps us add more solar panels in the future to meet our increasing daily needs for electricity.
How to connect your solar panels depends on:
- The type of your solar panels system,
- The solar power you want to generate,
- The other system components, such as a charge controller, battery, and inverter.
There are two main types of connecting solar panels – in series or in parallel. You connect solar panels in series when you want to get a higher voltage.
If you, however, need to get higher current, you should connect your panels in parallel.
Should you need both a higher voltage and a higher current, you have to apply both connection modes, which means that a part of your solar panels should be wired in series, while the remaining ones are to be wired in parallel.
The most important to remember is that both connection modes provide you with a higher wattage.
Therefore, if the power output of a solar panel cannot alone meet your daily electricity needs, you should think of adding more such panels to it, whether in series or in parallel.
To get the maximum efficient solar panel system, however, you should keep some basic principles related to connecting solar panels.
Wiring solar photovoltaic panels in series
As we said above, when connecting solar panels in series, we get an increased wattage in combination with a higher voltage.
Such ‘higher voltage’ means that series connection is more often applied in grid-tied solar systems where:
1) the system voltage is often at least 24 volts, and
2) the solar array output voltage is fed to an inverter or charge controller of a typically higher input voltage compared to off-grid systems.
Connecting in series means joining the positive terminal of a solar panel to the negative terminal of the next solar panel until eventually you are left with one free positive and one free negative terminal of the array, which are to be connected to the input either of the inverter (in case of a grid-tied system without a battery backup) or the charge controller (in case of a grid-tied system with a battery backup or off-grid solar panel system).
When you connect solar panels in series, the total output current of the solar array is the same as the current passing through a single panel, while the total output voltage is a sum of the voltage drops on each solar panel.
The latter is only valid provided that the panels connected are of the same type and power rating.
Let’s consider the depicted below solar panels designated for a 12V solar panel system, operating at their Maximum Power Point, while delivering the depicted voltage and current that correspond to this power tracking point.
Wiring solar panels of different ratings in series
Here is a series connection of solar panels of different voltage ratings and the same current rating:
You can see that if one of the solar panels has a lower voltage rating (and the same current rating) compared to the remaining panels, the output power is lower than in the previous example but the loss is not significant. Things, however, are entirely different if you connect in series panels of different current ratings.
You should, however, have in mind that the current produced from а solar panel depends on the ambient temperature, solar cells temperature, and solar irradiance.
How to squeeze more solar power from different solar panels by breaking the best practice rules?
You might say, I have these different panels.
I’ve bought them. It was a real bargain.
I don’t want to throw them away.
What can I do to squeeze the optimal solar power from them?
Yes, you can do that, but it requires some investment.
You should buy additional charge controller(s) and try to isolate these dissimilarities by implementing ‘Ideal Mixing.’
Here is an Ideal Mixing of different solar panels of the same voltage, connected in parallel, with the help of a charge controller:
Scenario 1. The solar panels and the charge controller are designated for the same system voltage.
In this case, you may use PWM controllers, if you are going for a low-cost solution.
The picture above depicts the connection of two different 12V solar panels: 100W (18Vmp x 5.5A Imp) and 50W (18Vmp x 2.77 Imp) designated for a solar power system of a 12V system voltage.
They might be, for example, one monocrystalline and one polycrystalline solar panel.
Or the pv panels from the same type(i.e. poly or mono) but produced by different manufacturers.
What is more, you may use this scheme not only to isolate dissimilarities between different types of solar panels but also to mitigate the differences, caused by the environment, between exactly the same photovoltaic panels. For example, by doing so, you will avoid the performance degradation when one of the PV panels is partially shaded during the day or pointing out to a sub-optimal direction.
Please, have in mind that this a simplified diagram. Hence, the additional equipment needed for combining these solar panels, like DC combiner boxes and fuses, are omitted.
What comes next is Ideal Mixing of different photovoltaic panels of the different voltages with the help of a charge controller:
Scenario 2. The solar panels are of voltage rating higher than the system voltage.
You have two different higher voltage solar panels, i.e., one 100W/24V and one 200W/24V that you want to connect to the already working 12 V solar power system comprising the two 12V 50 W solar panels connected in parallel from the previous scenario(see the picture above).
In this case, you have to use a step-down MPPT charge controller capable of stepping the 24 V solar panel voltage down to 12V.
Why MPPT charge controllers?
Why not using the low-cost PW controller you might ask?
Because the MPPT charge controllers convert the voltage difference between 24V solar panel and 12V battery bank to an increase in its output current that is twice higher compared to using a PWM charge controller.
With this twice higher current, the power provided at the output of the MPPT controller would be almost two times higher compared to the usage of a step-down PWM controller.
Please, have in mind that this a simplified diagram. Hence, the equipment needed for combining these solar panels and fuses need are omitted.
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How to Connect Solar Panels in Series and Parallel
Connecting solar panels in series and parallel are two common methods for increasing the voltage and current of a solar panel array.
When you connect solar panels in series, you connect the positive terminal of one solar panel to the negative (-) terminal of another solar panel. The total voltage of the array will be the sum of the voltages of each solar panel, while the current will be the same as that of the solar panel having the lowest current specifications.
When you connect solar panels in parallel, you connect the positive terminals of all the solar panels together and the negative (-) terminals together. The total voltage of the array will be the same as that of a single solar panel, while the current will be the sum of the currents of each solar panel.
The following are the formulas which can be used to calculate the total voltage and current for solar panels connected in series and parallel:
Formula for Calculating Solar panels connected in parallel:
Total Voltage = V1 = V2 = V3 = … = Vn, where V1, V2, V3, … Vn are the voltages of each solar panel.
Total Current = I1 I2 I3 … In, where I1, I2, I3, … In are the currents of each solar panel.
Please note that when solar panels are connected in series, the total voltage of the array will increase, but the total current will remain the same as that of the lowest current solar panel. When solar panels are connected in parallel, the total current of the array will increase, but the total voltage will remain the same as that of a single solar panel.
Connecting Solar Panels in Series (Practical Example)
For example, let’s say you have three 100W solar panels with the following specifications:
Voltage (V): 18V Current (I): 5.56A
In order to connect these solar panels in series, you will have to connect the positive terminal of the first solar panel to the negative (-) terminal of the second solar panel, and then connect the positive terminal of the second solar panel to the negative (-) terminal of the third solar panel, as shown in the diagram below:
The total voltage of the array would be:
Vtotal = V1 V2 V3 = 18V 18V 18V = 54V
The total current of the array would be:
Connecting Solar Panels in Parallel (Practical Example)
In order to connect solar panels in parallel, you will have to connect the positive terminals of all the solar panels together and the negative (-) terminals together. The total voltage of the solar panel array will be the same as that of a single solar panel, while the current will be the sum of the currents of each solar panel.
For example, let’s say you have three 100W solar panels with the following specifications:
Voltage (V): 18V Current (I): 5.56A
In order to connect these solar panels in parallel, you will have to connect the positive terminals of all three solar panels together and the negative (-) terminals of all three solar panels together, as shown in the diagram below:
The total voltage of the array would be:
The total current of the array would be:
Itotal = I1 I2 I3 = 5.56A 5.56A 5.56A = 16.68A
Parts List For Wiring Solar Panels in Series or Parallel
When wiring series vs parallel solar panels, there are a few things to consider.
The first is what type of solar panel to use.
There are two types: monocrystalline and polycrystalline.
Monocrystalline solar panels are more efficient but cost more. Polycrystalline solar panels are less efficient but less expensive.
The second consideration is the size of the solar panel array.
The size will determine how many solar panels can be wired in series or parallel.
Wiring solar panels in series increases the voltage while wiring them in parallel increases the current.
The final consideration is how to keep current in the solar panel safe, always a good idea.
The best way to do this is to use a voltage regulator.
This will allow you to safely wire multiple solar panels in parallel or in series without having to worry about overloading them.
There are a few other considerations when wiring solar panels, such as wire sizes and fuses, but these will vary depending on the specific application.
In general, wiring solar panels in series is better for larger systems because it increases the voltage and reduces the current.
Does Wattage Increase in Series?
In a world where technology is constantly evolving, it’s hard to keep up with the latest trends.
One such trend is the wattage race: manufacturers are constantly releasing products with higher and higher wattages. But does wattage increase in series?
To answer this question, we first need to understand what wattage is. Wattage, which is measured in watts, is the amount of power that a device consumes.
It’s determined by multiplying voltage by current. So, if you have two devices with the same voltage but different currents, the device with the higher current will consume more watts.
Now that we know what wattage is, let’s look at whether it increases in series.
In theory, it should – after all, if you have two devices with the same voltage but a different electrical current, wouldn’t they consume more watts if they were connected in series?
How Can I Increase My Solar Panel Output?
There are a few ways that you can increase the amount of power your solar panels produce.
One important consideration is to install more panels, which will obviously increase your output.
Another is to make sure that your PV panels are in direct sunlight as much as possible;
If they’re shaded by trees or another structure or simply just partial shading, the performance of your system output will be reduced.
You can also improve their efficiency by cleaning them regularly and keeping any debris or dirt away from their surfaces.
Finally, if you have an adjustable panel system, you can adjust it to face south (in the northern hemisphere) or north (in the southern hemisphere) for maximum sun exposure.
Can 12v Solar Panels be Connected in Series?
Solar panels are a great way to reduce your energy consumption and help the environment. But what if you want to install more panels to increase your power output?
Can 12v solar panels be connected in series?
The answer is yes, 12v solar panels can be connected in series. When connecting solar panels in series, the voltage of each panel is added together.
So, if you have two 12v solar panels that are connected in series, the resulting voltage would be 24 volts.
When connecting solar panels in series it is important to make sure that the wattage of each panel is the same.
If you have two 12v solar panels with different wattages, the highest wattage panel will determine the overall wattage of the system.
Choosing a higher voltage panel over a lower voltage panel will not give you any extra power output.
How to Wire Solar Panels in Series Parallel
Here’s a quick overview of how to wire solar panels in series and parallel. For more in-depth instructions, check out our full tutorial.
Series
To wire solar panels in series, connect the positive cable of one to the negative cable of the other.
Here’s a video showing you what I mean:
If you want to connect more in series, just connect the positive cable of each additional solar panel to the negative cable of your series string. You can string together as many panels as you want like this.
Parallel
To wire solar panels in parallel, you need to buy the appropriate branch connectors for the number of panels you’re wiring in parallel. (You may also need to buy inline MC4 fuses and connect them to the positive cable of each solar panel.) I’ll show you how to wire 2 panels in parallel using Y branch connectors.
To do so, connect the 2 positive solar panel cables to the compatible Y connector. Then connect the 2 negative solar panel cables to the other Y connector.
Here’s a video showing how to do this:
If you’re wiring more than two solar panels in parallel, pick the right branch connector for the number of panels you’ll be wiring in parallel.
H/T to Mowgli Adventures whose calculator was a big inspiration for this one. Their blog is amazing and you should definitely check it out!
How does a series solar panel connection work?
Let’s take a look at how we can connect some solar panels in a series circuit.
We’ll use an example of a series circuit connecting four 100 Watt solar panels. Each solar panel is 20 Volts and 5 Amps.
The circuit is formed by connecting the positive electrical terminal of one solar panel to the negative terminal of the next in a line and running a cable from each end of this line to the other components of our solar system. We can calculate the voltage current and power of this circuit as follows.
Total voltage = 20 Volts x 4 = 80 Volts
Total current = 5 Amps
Total power = 80 Volts x 5 Amps = 400 Watts
How does a parallel solar panel connection work?
When we take these same four solar panels and connect them in a parallel circuit, we run the cables from each panel separately into our solar system. We don’t join any of the solar panels together. We’ll see why this is important in a little while. This is what the voltage, current, and power of our parallel solar panel connection look like.
Total voltage = 20 Volts
Total current = 5 Amps x 4 = 20 Amps
Total power = 20 Volts x 20 Amps = 400 Watts
Even though the voltage and amperage of our series and parallel solar connections are very different, you can see that the final power output is the same.
So we’ve proved that there is no difference in the power output from a series or a parallel solar system when the voltage and amperage of all solar panels are the same. But things get complicated when you wire together panels with different voltage and amperage capacities.
The effect of mixing solar panels in serial and parallel connections
Now let’s make the same circuits with three 100 Watt solar panels of 20 Volts and 5 Amps and another 75 Watt panel of 25 Volts and 3 Amps. This is the total power of 375 Watts.
The difference here is that when you wire different solar panels in series, you need to use the lowest amp rating of all the panels.
Serial Connection
Total voltage = 20 Volts x 3 25 Volts x 1 = 85 Volts
Total current = 3 Amps (taking the lowest rating)
Total power = 85 Volts x 3 Amps = 255 Watts
Because we had to use the lowest amperage panel for the series connection, we ended up with a total power output of 255 Watts, resulting in a loss of 375 – 255 = 120 Watts of power.
Now, when you wire the same panels in a parallel connection, you need to use the lowest voltage.
Parallel Connection
Total voltage = 20 Volts (taking the lowest rating)
Total current = 5 Amps x 3 3 Amps x 1 = 18 Amps
Total power = 20 Volts x 18 Amps = 360 Watts
When using the panel with the lowest voltage for the parallel connection, we ended up with a total power output of 360 Watts, resulting in a loss of 375 – 360 = 15 Watts.
If you’re not careful when wiring solar panels of different capacities, you can lose a lot of power. In these situations, it’s essential to look at the ratings and calculate the effects of serial or parallel wiring. But there are also some other advantages and disadvantages of these wiring systems that you need to take into account.
Advantages and disadvantages of series and parallel wiring systems
Wiring
If you are running an electrical circuit with high amperage, you need a thick cable to carry the load. Think back to the water example, where you’d need a strong pipe to handle a powerful flow of water.
Wiring your solar panels in parallel means that you need cabling and components rated for high Amperage. If you use serial wiring for your solar system, there will be a higher voltage and low amperage, reducing the demands on your cables and components. If you’re uncertain about which wire size to choose for your solar setup, you might find our article on how to choose solar wire size.
The main benefit of parallel wiring
When you wire all your solar panels in parallel, the performance of one panel is not dependent on the performance of the other panels. But in a serial connection, if one solar panel is working at a lower capacity, it reduces the whole solar array’s performance.
This is important in case a panel in a series connection malfunctions. Also, if a particular panel in the series may be receiving less sunlight because of shade, the whole system’s power output will be reduced.
Summary
Now you have a good idea about the differences between serial and parallel wiring systems. Each has its benefits and drawbacks, and you’ll need to think carefully about which one to use.
If you plan to connect solar panels of different capacities, then a parallel connection is probably best. Parallel connections will help you avoid an underperforming solar panel lowering the output of your whole system.
But remember, depending on your specific system requirements and the specifications of your panels, it may be more complicated and potentially more expensive to wire and connect your solar panel system in parallel.
Perhaps one solution is to carefully check the placement and performance of your solar panels so that if you choose to wire them in series, you can minimize the risks of performance loss.
If you have any Комментарии и мнения владельцев or questions on this article about series versus parallel solar panels, then please share them here.