Poly Vs Mono Vs Flexible Solar Panels & Series Vs Parallel Circuit
When it comes to choosing solar panels that will work best for your needs, there are lots of variables that you need to consider: monocrystalline vs polycrystalline, hard panels vs flexible panels, wiring the solar panels in series vs parallel or a combination of the two.
This article will help bring clarity to these decisions you will need to make. Let’s start with the solar panels. As far as what we’re gonna discuss when it comes to solar panels, we’re going to talk about the difference between monocrystalline and polycrystalline, which are the tried-and-true heart framed solar panels. We are also gonna talk about the difference between those traditional panels and the newer, flexible solar panels. And the last thing we wanna talk about is how to wire your solar panels, whether you should wire them in series or parallel, and some advantages and disadvantages of each of those options.
Let’s jump right into monocrystalline versus polycrystalline. The major differences between these PV panels are going to be the durability and looks, the efficiency and size, as well as the cost per watt.
When it comes to durability, both of these PV panels are extremely durable. They have an aluminum frame with a tempered glass top to cover all the solar cells that produce energy. Manufacturers generally cover these photovoltaic panels for about 25 years, which is actually quite a long time when it comes to product warranties. Now, when it comes to weather, these panels are extremely resistant to all types of weather, including high winds and even medium-sized hail. The general rule of thumb is if the weather can damage your roof, it can damage your solar panels.
Now let’s talk about the efficiency and size of each of these PV panels. Monocrystalline solar panels are made with a higher grade of a silicon wafer. So generally they are more efficient than the polycrystalline panels (efficiency means the percentage of energy that is converted into electricity). So when it comes to monocrystalline panels on the high end in mass production, it’s about 20% (e.g.: Couleenergy Solar Module, CLM-330M-60 Series, Made of 158.75mm×158.75mm Full Square Mono PERC Cells); And when it comes to polycrystalline solar panels on the high end, it’s about 17% or so. Because mono solar panels are more efficient, their footprint is just slightly smaller than poly solar panels. If you have a 330 watt mono solar panel (1665mm*1002mm=1.67m²) compared to a 330 watt poly solar panel (1956mm*992mm=1.94m²), the mono solar panel is just gonna be smaller in dimensions won’t take up quite as much room as that poly panel.
P.S.: Solar panel efficiency is determined by two main factors: solar cell efficiency, based on the cell design and silicon type; and the total panel efficiency, based on the cell layout, configuration and solar panel size.
Now let’s discuss the cost per watt for each of these solar panels. In general, they are around the same, but because monocrystalline solar panels are producing with a higher grade of silicon, and that in turn means the manufacturing process is slightly more expensive, which then makes the consumer have to pay a little bit more for them.
10 years ago, when we produce our monocrystalline solar panels, it was really good if you could buy solar panels for about a dollar per watt. But as time has gone on, and as demand for solar energy has increased, the solar panel cost or solar panel price have gone down. Today you should easily be able to find both mono solar panels and poly solar panels (really high-efficiency solar panels) for about 20 to 25 cents per watt.
Now we’ll discuss the differences between those traditional solar panels that we just discussed and the newer, flexible solar panels (solar shingles). And again, we’re gonna talk about the durability and look, the efficiency, the size, and cost per watt.
Firstly, durability. The tempered glass old-school panels are really really durable. But when it comes to the flexible panels, they’re not as durable. There are issues like cupping scratches, micro-scratches, as well as tears that can happen to the solar cells because they don’t have the temper glass protection on the top of them. Another thing that they don’t have is a 25-year manufacturer’s warranty. Generally, flexible solar panels come with about a 5-year warranty because most manufacturers including some top solar companies don’t anticipate them lasting you that long.
Regarding the efficiency and size, these flexible solar modules maybe not as efficient as the old-school solar modules. So on a high end, or the average for these flexible modules is about 15-16% efficiency. And that’s not very good when you compare it to 17% of the polycrystalline photovoltaic modules and 20% of the monocrystalline PV modules. The difference in efficiency is gonna make you have to buy more PV modules. Or each PV module is gonna be larger in size and have a bigger footprint, bigger surface area to produce the same amount of energy. Now let’s talk about the size between the two types of solar modules. The traditional PV modules are significantly bulkier and heavier than the flexible PV modules. Obviously, that’s one of the major advantages that the flexible modules have over the traditional ones.
And when it comes to it, just to give you an example, a 180-watt 12V mono solar panel that we have on our RV is 11.5kg, and it is about three to four inches thick (including the mounts). To give you a comparison, you can get a 180-watt flexible solar panel that might be 2.4 kg in about less than half an inch thick. That’s really an amazing accomplishment.
Now pay attention to the cost differences between the traditional panels and the flexible panels. As you know, the traditional PV panels will run you anywhere from 20 to 25 cents per watt, providing for a decent quality panel. And we did a quick search online to check the prices of the flexible panels. We found a 180-watt flexible panel for over $200 which will run you about $1.1 per watt, pretty more expensive. That’s over 5 times the amount for any other solar panel that you can look for. They’re going to run you an arm and a leg. And yeah, if you have healthy pocketbooks definitely go for the flexible solar panels.
But don’t worry, you may get a good price for the best possible flexible mono PERC solar panels with Shingled Technology at Couleenergy.
All right, guys, now we’re going to jump into the final topic, and that has to do with wiring solar panels in series and/or parallel. This topic can be extremely confusing. And our goal with this little section is to try to make it as clear and easy to understand as possible. Before we jump into it. We want to refresh our minds on the relationship between WATTS, VOLTS, and AMPS. As you may remember that we discussed how watts is equal to volts times amps. This equation is going to be very important as we go through our scenarios today. When we illustrate how to wire in both series and parallel, we’re going to use our personal system as a reference to illustrate those concepts. So we have four 330 watt mono PV panels for a total of a 1320-watt solar array. We know we have 330-watt mono solar panels at 33.8 volts, and that gives us about 9.77 amps of current on each of those monocrystalline solar panels.
Now, the first thing to talk about is wiring them in series. When you’re thinking about wiring your photovoltaic panels in series, you need to think of the PV panels as being tied into a string. You’re taking each one of these 330 watt PV panels, and you are marrying them or combining them into a singular 1320-watt solar panel. This is in an electrical sense, not any physical sense. Obviously, they’re gonna remain four separate mono PV panels, but in an electrical sense, you are going to be wiring them into a single 1320-watt photovoltaic panel. Now let’s talk about what changes with the solar PV array when you do that. When you’re wiring all of these monocrystalline photovoltaic panels together, you’re gonna take the positive line on a one-panel wire to the negative line, and another take that positive line wire to the next negative line, and so on and so forth. So what you’re left with is, a singular 1320-watt mono PV panel that has a single negative wire coming out of it and a single positive wire coming out of it.
What changes when you do this process is the voltage of your PV system. What you need to remember is when you wire things in series, the only thing that changes with this system is the voltage. So when you’re wiring four 33.8V Couleenergy mono PERC solar panels together, you’re gonna take that 33.8 volts and multiply that by four, which will give you 135.2 volts. So now you have a 1320-watt solar panel that is 135.2 volts. And if you reference that equation that we just talked about, watts equals volts times amps, you have your watts which is 1320W, you have your volts which is 135.2V, but you don’t have your amps. So to solve that equation very easily, you just take the watts 1320 divided by 135.2V, which is your votes, and that gives you 9.77 amps. So you have a 1320-watt photovoltaic system at 135.2 volts and 9.77 amps.
Now the series is done. Let’s talk about wiring them in parallel. When you’re wiring these four monocrystalline solar panels in parallel. It is almost the exact opposite. Each of those 330-watt PV panels is going to remain as separate solar panels. They’re gonna be individual solar panels producing individual amounts of energy at 33.8 volts. The only thing that’s gonna change when you wire all of these in the parallel is a positive and negative one comes out of one PV panel, a positive and negative line comes out of the next one, and so on and so forth. None of them are connected together. The only thing that changes is the amps of your solar array. So you still have a 1320-watt solar array at 33.8 volts. And again, let’s go back to our watts equal to volts times amps equation. If we need to find the answer for that PV system wired in parallel, you take these 1320 watts and you divide that by 33.8 volts, and it gives you 39.08 amps. Now that 39.08 amps, as you might have guessed, 9.77 amps from each panel multiplied by four, because we have four mono solar panels. So 9.77 times four gives you 39.08 amps. So the only thing that changes when you’re wiring a solar system in parallel is the amps. Your quadrupling the amps.
Ok, now we understand how to wire in both series and parallel, what you need to do is figure out what the advantages and disadvantages are between those. We’ll go through with wire sizing, shading issues, and the charge controller size.
As far as wire sizing is concerned, if you don’t know already, wire size is directly correlated with the amount of amps running through that wire. So each wire is rated for a specific amount of amps of current flowing through it. So the smaller the amount of amps, the smaller the size of the wire. Remember that our 1320-watt mono PV panels wired in series were 135.2 volts at 9.77 amps, and in parallel were 33.8 volts at 39.08 amps. You’ll find that the ones wired in series are going to be much smaller wires coming off the mono solar panels than the ones wired in parallel.
Now when it comes to shading, that’s where the advantages in which the wiring in parallel is a major advantage. Remember when we were talking about wiring solar panels in series, you’re marrying them all together. So it’s a singular unit. All those PV panels are working together to produce that energy. If one of those monocrystalline solar panels is shaded, the entire unit goes down. And this has to do with the fact that this is how solar panels work. If you have a single 330-watt mono PERC solar panel, and that monocrystalline solar panel is shaded, that solar panel stops producing energy. The only reason the entire solar PV system goes down when you’re wired in series is that you wired them all together. So each one depends on the other. The reason is the advantage when it comes to wiring solar modules in parallel is because all of those mono solar modules are individual modules. If one PV module gets shaded, you’re only down twenty-five percent of your PV array. The remaining three of your four mono solar modules can still produce energy. Today some leading manufacturers (top solar companies like Jinko Solar, Risen Energy, Longi Solar, Canadian Solar, JA Solar, Couleenergy, Trina) have applied the parallel connection in their half-cut cell solar modules.
The last thing we wanna talk about is the size of the charge controller. Well, when you think about the amperage coming from the solar panels, there are more amps coming from the PV panels wired in parallel versus the PV panels wired in series. So a solar panel system wired in parallel will need a much bigger charge controller.
Okay, guys, I hope that wasn’t that confusing and not muddy the waters anymore. But there is a 3rd option that you can do when wiring solar PV panels. You can wire them in series and parallel, meaning if we took two mono 330Wp solar panels and another two, and to wire those together in series, you would have 660 watts 67.6 volts mono solar panels. Because we know that wired in series doubles the voltage. And then you will take both of those 600 watt 67.6-volt mono panels and wire them down in parallel. As you know, with parallel, we’re going to double our amperage. So the specs for that system would be 1320 watts at 67.6 volts and 19.54 amps. That’s the 3rd option, it is kind of blends and is the best option in most cases.
Obviously, we just use this one particular illustration as an example to explain these concepts to you. Of course, you can change the size of your solar power s. You can change the number of PV panels. You can change all of that. So remember when we said solar was virtually limitless. This is exactly what we mean. It is very confusing. But once you understand all the concepts, you’ll realize how things kind of intertwine together and start to make a lot more sense to you.
If this article doesn’t make sense to you right now, we encourage you to go out and do more research so that you can come back and really digest what we are saying in it. Anyway, we hope you enjoy this article. If you did and potentially learn something along the way, please give us a like below. Thank you!