It is ok to mix solar panels of different watts for installation?

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Solar panels having different watts can be used together for installation. But the question now is if they are ideal for our solar work. Connecting different wattages of solar panels comes with many effects depending on how they are being connected. The effect on the efficiency of the system is what I will be discussing in this article.

Before diving into the effects it has on the system. let’s look at the different ways different watts of solar panels can be installed. And the effect it has on the different methods.

Solar panel of different watts installation

Different methods of connecting solar panels.

Solar panels have many ways of connecting them, depending on the power we want to generate with them. They are either connected in series, parallel, or series-parallel.

How to install a solar system at home or offices.

Series connections solar panels and what watts we expect from the connection.

To connect the solar panels in series, connect the negative terminal of a panel to the positive terminal of the second panel. Then the output will now be the positive terminal of the first panel and the negative terminal of the second. Continue connecting the negative to positive terminal of each panel cable till the whole panels are connected. Them take your output from the first terminal of the panel and the last terminal the panel.

let’s say we are having 4 × 300watts panels by 12V and 25Amps. We are to connect them in series. This is the power we will end up getting from the series connections.

The voltage of the panels after the connection will be;

12V + 12V + 12V + 12V = 48V.

While the amperage of the panel after connection in series will remains the same.

48V × 25A = 1200watts.

From the above calculations we can see that the efficiency the panel is 100%.

As you can see in this series connection of the panel, the voltage of the panel increases but the Amperage remains the same.

Parallel connection of solar panels and the watts we expect from the connection.

To connect panels in parallel, all we need to do is to connect all the positive terminals of the panels. And the same time connects all the negative terminals too together. Then the panel output will be the joined positive terminal and the joined negative terminal.

Now, when we try connecting the same panel we connect in series before to parallel, we will achieve the following values.

in this case of parallel connections, the voltage of the panel will remain the same as the Amperage increases.

So the Amperage of the panel will be,

25A + 25A + 25A + 25A = 100A.

While the Voltage is 12V.

The efficiency of the panels are 100% because 100A × 12V = 1200watts.

Series – parallel connections and the power we except from the connection.

Yes, solar panels are also connected in series parallel. This can be achieved by connecting in series and then merging the series connected ones in parallel. In this aspect, we will still look at what happens when our solar panels are run on this type of connection.

So let’s say we are to connect 8 × 300Watts 12V and 25A panels each. And we are to connect 4 × 300watts in series each and then merge the two to parallel.

When we connect 4 × 300watts in series. What we will have is, 48V and 25A.

So now we are to parallel the two sets of panels connected in series.

When we connect 48V, 25A in parallel with 48V, 35A we get, 50A, 48V.

From our calculations, we can say that solar panels are 100% efficient. Because 50A × 48V = 2400Watts.

From the above panel connections discussions. When we connect the same size of the panel. You can observe that the efficiency of the panels remains 100% regardless of how they are connected.

So, now let’s look at how the connection of different sizes of solar panels affects the system.

how do connections of different sizes of solar panels affect the system?

Whenever we try connecting solar panels of different voltage and watts. These are the things that happen to the system power.

If they are installed in series. The two different voltages will add up. Then the amperage of the highest panels tries to balance the lower Watts. By so doing the amperage will automatically drop to lower Amp.

When they are connected in parallel. The amperage of the panels will add up. While the voltage of the highest panels tries to compensate with the lower voltages of other panels. And by so doing the total voltage will then drop. In this case, you will be observing sparking when trying to connect the panels if they are exposed to sunlight.

The outcome of connecting different solar panels watts in series connections.

Installation of different solar panels watts can affect the efficiency of the systems and make the watts drop. Here mathematical we can see how these effects occur. You don’t need to panic about the maths or calculations involve as it is just simple maths.

now let’s say we are having 3 × 300watts panels with 12V, 25A, and 3 × 150Watts panels by 5V and 30A and we want to connect them in series together.

we are to watch what those panels will give us, after connecting them and how much efficiency the system will have.

So what we have to do now is to add up the voltages of the whole panels.

12V × 3 = 36V

5V × 3 = 15V

Now the total voltage is to add up the two volts. Which is 36V + 15V = 51V.

The fact that the system is having two different Amps, 25Amps, and 30Amps. So the system chose the lowest Amps which is 25A.

What is system is now having is, 51V and 25A (amperage). What the system is now having is 51V × 25A = 1275Watts.

Whereas the maximum power the system suppose to deliver is 1350Watts. We can now see the power we lose for the installation of different watts of solar panels.

Effects of connecting different solar panels watts in parallel.

Now let’s try connecting the same panels in parallel to know how much value it will give us.

Let’s have in mind, what we discussed earlier when different panels are connected in parallel, the decrease.

So let’s add up the amps of the solar panels,

20 + 20 + 20 + 30 + 30 + 30 = 150A.

because the system is having two different voltages, the voltage will not add up, instead, it now chose the lowest volts.

150A × 5V = 750watts.

As we can now see that the system which is capable of generating 1350watts ends up generating only 750watts because of the mix panel connection.

What if we connect panels with the same volts and different watts?

We can have 3 × 100watts, panels of 10V, and 3 × 300watts, 10V. From both different panels we have a panel with the same volts, but different amperage.

Let’s try to connect the panels to see what the output power will look like.

When we connect the 100watts panels in series, it will give us, 30V and 10A. When try connecting the 3 × 300watts in series too, it will gave us 30V 30A.

If we then connect the both panels ( 10A, 30V and 30A, 30V) in parallel, it will then give us the output of 30V, 40A.

We got this by adding the two Amps and then maintaining the 30V as the two volts are the same.

So from the output, we can see that the efficiency of the system is 100% because if we multiply the 30V and 40A it will give us 1200watts. Which is the maximum power of the combination of those panels.


During the installation of our solar panels, is ideal choosing panels of the same size in watts and volts. But when the same size is not available one can easily build up the panel to arrive at the same voltage and runs the connection.

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