Solar Panel Voltage - Nature's Generator

Solar energy’s popularity has been growing in the past couple of years. Awareness about its benefit to Mother Earth and one’s electricity bill continues to spread. That is why many are starting to install this clean source of energy in their homes and businesses. 

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If you are thinking of doing the same thing but find it a bit daunting, and you want to know how it works. Don’t fret. In this post, we’ll discuss how solar panel works, what’s the solar panel voltage, how to measure it, and the factors that affect it.

The Solar panel voltage: The Most Visible Component

When you think about solar energy, one of the first things that come into mind is either a single rectangular blue with a grid or rows of this rectangular blue on an open field. It is also called a photovoltaic (PV) panel. The standard solar panel voltage is between 12 volt and 24v solar panel. It is made of solar cells, which both have a negative and positive layer allowing it to create an electric field. 

Once the sunlight hits the panels, an electric current is produced. This current is then moved by voltage then goes through the wires and components of the system like Nature’s Home power backup.

The two most common types of panels are monocrystalline and polycrystalline panels. The light blue panels which we’re more familiar with are called polycrystalline panels. The black panels are the monocrystalline ones. In essence, the:

• Monocrystalline solar panels are produced from a single silicon crystal, while 
• Polycrystalline solar panels are created out of many silicon crystal fragments that are mixed during the manufacturing stage.

Monocrystalline panels have a higher efficiency but are more expensive because of their complex manufacturing process. And, to reach the same power output as its counterpart, polycrystalline panels needed to be installed more. They are cheaper and less efficient.

You can check out this article What is the Difference Between Polycrystalline and Monocrystalline Solar Panels for more information on the difference between the two kinds of solar panels.

Solar Power Voltage Terms to Familiarize and How it Works

It is important to get the numbers right as you don’t want to overload your inverter or underutilize your home power backup. But to help you understand more about pv panel voltage and how it works, here’s a list of terms to familiarize:

• AC Volts - refers to the converted voltage from DC Volts to AC Volts.
• Nominal Voltage - is a reference on the voltage class your circuit or system is under such as 300 volts, 120/240 volts, etc. This is different from the operational/operating voltage (i.e. if you have a 240-volt circuit but it is operating at 234 volts).Actual Voltage Measured Under Load - is about the circuit’s actual voltage once an appliance has been connected.
  
• Voltage Maximum Power (Vmp) - is measured with a multimeter. It refers to the solar panel’s maximum capacity when connected to a load. The actual VMP will differ throughout the day due to shading, temperature and other factors.
• Potential or Open-Circuit Voltage (VOC) - is the circuit’s voltage measurement when not connected to a load.

With this knowledge in mind, let’s take a look at how it works.  

• A standard solar panel is made up of 36 crystalline cells. And, those cells are quite powerful:
• A cell’s voltage under load is at 0.46 volts which is about 3 amperes of generated current;
• Each cell inside that panel can generate 1.38 watts, approximately;
• A single cell has about 0.5 to 0.6 of open-circuit voltage;

In short, a solar panel has:

• Peak Open-Circuit Voltage Output: 18-21 volts, and
• Actual Voltage Measured Under Load: 12-14 Volts.

This is just about enough to power a 12-volt battery.

4 Factors that Affect Solar Panel Voltage

The type of panel used for your solar power system plays an important factor in your output voltage requirements. Other external reasons can cause the panel's voltage output to fluctuate. Some of them are the following:

• Panel Orientation 

To reach the peak performance and maximum of the solar panels and their output voltage, it is a must to ensure that they are tilted towards the sun. While having them lay flat is okay, being in a tilted position meant more sunlight hits their surface at a perpendicular angle. This allows for a more efficient conversion of solar energy to electricity.

• Shading and Location

It is important to make sure that the panels or any of their parts aren’t shaded. Having an unobstructed view of the sun meant they can soak in all the energy and be efficient in storing them.

Shaded cells aren’t able to generate as much electrical energy as the cells that are fully exposed to sunlight.

That is why it is also good to note if you live in an area that gets to experience more peak sun hours.

For those living in Arizona, a 400-watt panel can produce at least 3 kWh of electricity since it has 7.5 hours of peak sun hours. Meanwhile, if you’re living in New Jersey, the same 400-watt panel can only produce 1.6 kWh of electricity because it only has 4 hours of peak sun time.

• Temperature

Like any appliance or gadget, a solar panel’s performance is also affected by the temperature. The voltage output decreases as the panel’s temperature increases. This is because the electrons within the solar cells move slowly the higher the temperature is. Thus, resulting in a reduced amount of generated electrical energy.

• Panel’s Age and Maintenance

Cleaning the panels regularly is necessary to make sure that they receive the right amount of sunlight. Remove any debris and dust that accumulated on top of the panels to avoid a drop in the production of electricity. 

Like any gadget you own, wear and tear also affect the solar panel output voltage a.k.a. the panel’s efficiency. 

Typically, solar panels degrade at about 0.5% per year. So, if you have had the panels for 25 years, their efficiency is down to 85%, which is still enough to lower your utility bills. 

To achieve this slow degradation rate, it should be a must to regularly check on the status and quality of each part of the panel and its system. After all, as cliché, as it may seem, prevention is better than cure. Or in this case, way better than wasting your savings.

To put it all together…

One of the first things that come to mind when thinking about solar energy is rows of solar panels on the open field or the roof. After all, they are the most visible component of this renewable energy system. 

Determining the solar panel voltage and how much solar input it needs are required when building the perfect home battery backup for your home or business. But there are factors to consider that may affect the efficiency of the output voltage, such as temperature, location, shading, panel orientation, and age and maintenance.  

Regardless of how tedious the research work can be, the long-term use of solar energy is worth every time and money spent because of its benefits to one’s savings and nature.

If you're looking to switch to solar, you may wonder if you have enough space to install the panels. This is a valid concern - solar panels are pretty big! Most home solar panels are about 5.5 feet x 3 feet and weigh roughly 40 pounds each.

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Most of the time, you won't see the size of solar panels expressed in feet. Instead, you'll see it's listed as the number of solar cells within a panel, with the most common solar panel sizes being 60-cell and 72-cell.

Let's take a closer look at the difference between these solar panel sizes and how to pick the right one for your home.

Calculate the costs and benefits of installing solar on your home

How to measure solar panel size

When you look at a solar panel, you’ll see it’s made up of small squares. Those squares are called solar cells, and they're the part of the panels that turn sunlight into electricity.

You'll see the size of a solar panel described by how many cells it has. 60-cell panels are usually laid out in a 6 by 10 grid and are the most popular option for home solar installations. You’ll typically find that 60-cell solar panels have output ratings between 350 and 400 watts and efficiency ratings between 17% and 19%.

72-cell panels, on the other hand, are usually arranged in a 6-cell by 12-cell grid. Because 72-cell panels hold more cells, they are bigger and can produce more solar power, making them popular for commercial installations. 72-cell panel wattage usually sits around 415 to 450 watts, but they can get into the 460-watt range. Their efficiency ratings are typically between 18% and 21%.

Solar panel dimensions and weight

Many people want to know the physical size of solar panels, not just how many cells the hold. The average 60-cell solar panel is about 65 inches by 39 inches, or 5.4 feet by 3.25 feet, and weighs around 40 to 50 pounds. The actual dimensions will vary from panel to panel, so we’ve listed a few for some of the most popular 60-cell panels on the market:

72-cell panels are larger, about 80 inches by 40 inches and about 1.5 inches tall. This works out to just about 6.5 feet by 3 feet for 72 cell panels, give or take a few inches. 72-cell modules generally weigh around 50 pounds. Here are the dimensions for 72-cell panels offered by top brands:

Pros and cons of 60-cell and 72-cell solar panels

Here’s a brief breakdown of the pros and cons of each panel size.

How big are portable solar panels?

Once solar panels are installed on your roof, you don’t have to think much about their size anymore. 

But, with portable off-grid panels, solar panel size is one of the most important things to consider. Your RV might only have a small amount of roof space, or you might want something you can carry around and set up outside your campsite!

Because portable solar panels are made for travel, they tend to be smaller and have about 40 cells as opposed to 60. 200-watt portable panels are around 5 feet by 2 feet. 

You could also opt for flexible solar panels, which also measure about 5 feet by 2 feet. But flexible panels can bend and are much thinner than crystalline panels, so they’re easier for storage.

The flexible panel sold by Renogy, a popular portable solar brand, has 72 cells, but they’re smaller than the ones used in typical commercial panels. The panel is also substantially lighter, weighing just 10.8 pounds!

Folding solar panel kits are also an option for portable use. Foldable panels can be small enough to fit in your backpack, or large enough to power your RV - there's a wide range of options out there.

Factors that are more important than solar panel size

There are many factors that you should consider before the size of your solar panels, like solar panel efficiency and solar panel warranties. 

Solar panel efficiency

Solar panel efficiency is the percentage of light that strikes the surface of a panel that is converted into usable electricity. Modern solar panels have efficiencies that range from around 17% up to 22.8% in some premium models.

Highly efficient panels take up less space, which will allow you to fit more panels on your roof.

Solar panel warranties

There are two types of warranties that cover solar panels.

The first is the product warranty. This is the period during which you can ask the manufacturer to replace the solar panel should any problem arise. Nowadays, a product warranty of 12 years is standard, but more brands are starting to offer product warranties of 25 years.

The second type of warranty is a performance guarantee. Most mainstream panels have a 25-year production warranty, guaranteeing the panel will produce a certain level of output at every stage of the panel’s life. From the date your panels are installed up until the 25-year mark, the minimum guaranteed output of your panels will gradually decrease.

You can expect an output of close to 100% for year one, gradually down to between 80 and 92 percent for year 25. This loss in output is technically known as solar panel degradation. Some solar panel manufacturers, such as Canadian Solar, even offer a 30-year performance warranty on certain panel models.

Find out if solar panels are worth it for your home

How to find the best solar panel size

The easiest way for homeowners to figure out the best solar panel size for their needs is to work with a dedicated solar installer. Solar installers will size your system based on your energy needs, coupled with your available roof space and the sunlight in your area. They can recommend a system size that can fit on your roof and reduce or eliminate your electric bill. 

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