As we know, Solar cells are a popular source of power today. But the total efficiency of this source depends upon the systems that are used for electricity. The 12 volts solar system is called the traditional system as it has been used for a while now. Compared to that, the 24 volts solar system is newer but with more potential.

The central aspect of this article is finding which system is better for off-grid use, 12 volts system or 24 volts system, from the narrating of the pros and cons, you can conclude which power system is a better option for off-grid usage. However, it is up to the users to decide which one they need.

Solar energy is a popular source of power nowadays because it is free and renewable. But this concept still needs to walk a long path for commercial use. Today, we use solar energy for small consumption of power, like for homes or recreational vehicles. In many countries, solar energy is used for traffic control purposes.

Traditional cells usually can produce 12 volts. With the advancement of technology, we now have cells with higher capacity. In this article, we will discuss the traditional 12 volts system and 24 volts system, their use, and their advantages and disadvantages.

12-volt cells were considered a standard before the introduction of new technologies. Today, 24 volts and 48 volts systems are more popular. The basic difference between 12 volts and 24 volts systems is that 24 volts systems can produce more electricity than 12 volts. Since the cost-benefit relationship’s efficiency is a vital tool of measurement, we will discuss them briefly in later sections of the article.

Solar power is excluded from grid production mostly because it has not seen any large-scale application yet. Since it is cheap and renewable, researchers are showing promise for developing solar energy systems. 24 volts solar systems hold more significant potential than 12 volts systems. That is why a comparison between these two systems is necessary.

What is a Solar Cell?

A solar cell is a panel mostly made of silicon. This panel works by the principles of the photovoltaic effect. When sunray hits the panel, it directly converts light energy to electrical energy. It does not require any chemical reaction to produce electricity. Instead, it uses photons (light energy) to produce DC voltage directly. The solar cell, also known as photovoltaic cells.

Solar cells or PV cells are of 2 kinds, p-type cells, and n-type cells. The p-type cells use p-type semiconductors. N-type uses n-type semiconductors. The semiconductors are made of silicon as it provides better efficiency than any other materials. Although Gallium Arsenide is also a popular material. [news.energysage.com]

The first-ever cell was built in 1889, which yielded only 1% efficiency. But today, a general solar cell can provide 33% efficiency. The most popular system of solar power system is 12 volts. But there are higher voltage systems with 24 volts and 48 volts. 12 volts system is commonly used for boats and recreational vehicles, while the other systems can be used for houses or plants.

History of Off Grid Solar Power Systems

The development of solar power energy began as early as 1839, with the discovery of the photovoltaic effect by French physicist Alexander Edmond Becquerel

Father of solar cell, Edmond Becquerel. celebrityborn.com
In 1875, William Grylls Adams saw that if selenium is exposed to the sunlight, it will produce electricity.

Charles Fritts built the first complete solar cell about 50 years after Becquerel’s discovery. He used a selenium semiconductor with a thin gold coating. Though his cells could only transform 1% of light energy to electric energy, he is known for his vision of this clean, renewable energy. [energysage.com]

In 1953, 3 scientists, Calvin Fuller, Gerald Pearson, and Daryl Chapin, invented the silicon made solar cell. This time, the cells would produce enough electricity to power small electric machines.

Three years later, the first-ever commercial solar cell was launched. It would cost about $300 per watt, and only the rich people could buy it.

In the late 1950s and 1960s, the USA and the Soviet Union used solar cells for their space missions. It became a common source of power for spacecraft later in the decade.

By the 1970s, cost minimization of the cells became possible, and it would cost only 20 dollars per watt. Exxon made this cost-lowering possible. [energysage.com]
From 1970 to 1990, solar cells gained more popularity. Today’s technologies are somewhat similar to the late 90s.

Today a usual solar power system would cost about 2 to 3 dollars per watt and provide up to 33% efficiency.

Solar Cell Design

A typical solar cell is 10 cm x 10 cm. The main section is made of silicon with glass or plastic edging. One cell alone can only produce 15 to 20 percent of the energy that inflicts on its body. Multiple cells are installed in series or parallel combinations to increase power generation. Usually, a complete solar system consists of cells, cable circuits, storage batteries, converter or inverter, voltage controller, etc. [britannica.com]

Gallium Arsenide is also a popular material for building solar cells. This material provides almost the same efficiency as silicon-powered cells. The following process produces the cells:
⦁ Interconnect process: This is the first step. In this process, materials are interconnected in the cells. Both p-type and n-type connections are made.
⦁ Insulation process: Next, the materials are insulated in the cell sheet.
⦁ Routing process: The insulations are routed according to the need is this phase.
⦁ Back panel installation: In this phase, back panels are installed. Usually, the back panels are shockproof and work as the baseplate of the cell.

Working Principles of Solar Power Systems

Solar power systems use the principles of the photovoltaic (PV) effect. When sun rays hit certain materials, they absorb photons and release free electrons. This produces a direct current within the cells.

That direct current is then transformed into alternating current through converters. The panels can produce little electricity each. Modern systems use concentrated solar power—arrays of mirror concentrate sunray. The concentrated sunray is then exposed to a solar tower, which can produce more power.

The PV effect is similar to the photoelectric effect. But the main difference is PV effect releases electrons within the material, which generates electricity, and the photoelectric effect releases electrons in space. [energysage.com]

Working principle of a solar cell. solarcells.com
There are three solar power systems. They are:
⦁ Direct solar power systems
⦁ Off-grid solar power systems
⦁ Grid-connected systems

An off-grid solar system. embetronsolar.com
The general formula for calculating annual electricity production from a solar system is:
E = A * r * H * PR
Here,
E = Energy (kWh)
A = Total solar panel Area (m2)
r = solar panel yield or efficiency (%) 
H = Annual average solar radiation on tilted panels (shadings not included)
PR = Performance ratio, coefficient for losses (range between 0.5 and 0.9, default value = 0.75)
[pveducation.org]

12 volts and 24 volts systems

12 volts systems are the most popular solar power systems to date. It is mainly used for recreational vehicles (RV) and boats. 12 volts systems use standard components like 12 volts solar panels (cells), storage batteries, inverters, cables, etc. Usually, the elements are arranged within close distance, usually 50 feet. This system only uses 12 volts deep cycle batteries and 4-gauge wire cables; it can pass up to 60 amperes current without voltage loss. But longer cable may reduce efficiency because of resistance. The solar charge controller is used for 12 volts systems, and the components are installed parallelly. As mentioned, this system applies to a small demand for energy.

Compared to that, 24 volts systems are relatively new, and they are used when power demand is more significant or can travel a greater distance than 50 feet. Unlike 12 volts systems, it can fulfill power demand for small house operations.

24 volts systems can use the same components as 12 volts systems. How? By merely changing circuit orientation. If 12 volts system components are installed in a series orientation, it will work as 24 volts.

But separate system components are available for 24 volts systems today, with 24 volts panels, batteries, inverters, etc. [quora.com]

⦁ For both systems, the principle is the same. But there are some differences, such as:12 volts system components are closely oriented, usually within 50 meters. But 24 volts system can cover a greater distance.
⦁ 24 volts systems can produce more power than 12 systems.
⦁ One can build a 24 volts system with 12 volts system components, but the reverse process will reduce efficiency drastically.
⦁ 24 volts systems can be installed to power small house operations but for 12 volts systems, the usage limit stops for boats and RVs.
⦁ Apart from other components, inverters will have to be separate for each system.
⦁ 12 volts solar panel can produce up to 180 watts, whereas 24 panels can produce up to 400 watts.

Comparison of 12 volts systems and 24 volts systems

Now that we have discussed the fundamental differences between the two systems let us discuss each system’s advantages and disadvantages.

12 Volts System Advantages

⦁ Firstly, 12 volts system components are cheaper and readily available. Users will not have to search for the parts intensely.
⦁ Most of the home appliances will not need more than 12 volts to operate, so there is no extra voltage.
⦁ Since 12 volts systems are closely packed, users will not need a huge space to install the system and also provide excellent efficiency.
⦁ This system is very easy to maintain because components of this system are widely available.
⦁ 12 volts systems are easy to scale; users can add more panels and batteries without shedding any sweat.

12 Volts System Disadvantages

⦁ As the components are designed for 12 volts systems only, batteries and regulators can not step up easily to a higher voltage.
⦁ Wiring systems for 12 volts components are expensive compared to higher voltage systems.
⦁ 12 volts systems are closely oriented, so users can not stretch the system without losing efficiency.

24 Volts System Advantages

⦁ A 24 volts system significantly reduces wiring costs more than the traditional 12 volts system because increased voltage reduces the current through the wire passage. So, the user will need fewer cables, saving the rest.
⦁ 24 volts systems are more reliable for AC appliances, and most of the machines today are designed to work with AC.
⦁ Users can easily step the voltage down in a 24 volts system to match the machine’s need, using a regulator.
⦁ Users can build a 24 volts system with 12 volts system components. When 12 volts panels are oriented in a series combination, they will work as 24 volts panels. Batteries will have to be arranged in the same way. However, the solar charge controller will not work in the same way.
⦁ Compared to the 12 volts system that uses a solar charge controller, the inverter is cheaper to use in 24 volts.
⦁ More voltage heats the wire, which raises conductivity, providing efficiency.

24 Volts System Disadvantages

⦁ Since most home appliances can work with 12 volts, 24 volts systems somewhat overproduce voltage and have to step down in such cases.
⦁ Components of 24 volts system can be hard to find in local stores, but it does not count as a problem with the progress of online shopping.
⦁ 24 volts system can be annoying for RVs or boats because users will have to step down voltage, which may cost extra money.

From the above discussion where both systems have their pros and cons, it is difficult to provide one suggestion for every situation. But it is clear that for smaller power consumption, 12 volts system is a better option. That is why traditional 12-volt systems are more popular. But the power demand is rising every day.

This leaves less room for 12 volts systems. Moreover, the 24 volts system has some competitive advantages over the traditional system. So, the 24 volts system is more acceptable for today’s situation. But again, users must define their needs and select a power system later. [kyocera.com]

Installation and Maintenance of Solar Power Systems

Although the difference between voltage levels, every solar system has somewhat the same installation process. Usually, distinguished engineers do the work for the clients; the process is as follows:

⦁ First of all, the user has to find the sweet spot he wants to install the system, on the roof or the yard, or anywhere else.
⦁ When the installation place is fixed, mounting of the panel support system commences. The system is tilted up to 18 to 38 degrees. This angle creates to expose the panels to gain maximum sunlight.
⦁ Mount the panels on the support system tightly
⦁ Next, wire the panels.
⦁ After finishing wiring, solar inverters and chargers should be installed. Usually, they remain close to the mounted panels to balance efficiency.
⦁ Attach solar batteries with inverters and chargers. Batteries are used to store power for rainy/cloudy days.
⦁ The final installation task is to connect the batteries and inverters to the house’s main power line. A meter is usually attached to the system to monitor power generation.
⦁ The system should be ready for usage. [altenergy.org]
Off-grid solar power systems need very little maintenance. But once or twice in a year, the user may do the following things:
⦁ Clean the panels to maintain sunlight absorbance of the panels.
⦁ Avoid cleaning with cold water as it might damage the heated panels.
⦁ Check the condition of the inverters and batteries.
⦁ Change wiring when necessary.

Facts about Solar Power Systems

Here are some interesting facts about solar power systems:
⦁ Solar power is the most available and renewable source of energy on Earth.
⦁ Today solar panel costs $0.39 per watt, falling about 99% percent from the first invention of solar panels which cost $77 per watt.
⦁ A solar power system can last up to 44 years easily.
⦁ Energy from solar power plants is cheaper than fossil fuel and natural gas.
⦁ China is the leading country to utilize solar power by a great margin, producing about 50 gigawatts of power a year.
⦁ Most of the solar power plants in the USA are situated in California.
⦁ Solar energy systems are one of the fastest-growing sources of energy worldwide.
⦁ Solar panels are so popular that you might find a solar power system near your home or workplace.
⦁ The solar power system is pollution-free.
⦁ Solar panels are even used in space stations. [conserve-energy-future.com]

Futuristic technologies for solar power systems

Let us have a look at the next-generation solar power systems.

⦁ Bio-solar cells: The biological solar cells or bio-solar cells are the most promising futuristic technology for solar power systems. This cell uses bacteria to increase the photon consumption rate of the cells. The particular bacteria is called cyanobacteria. They can be found almost everywhere. The technique is to produce extra electricity from the photosynthesis and respiratory activity of the bacteria. Though the production increases very little than the traditional cells, it holds outstanding potential.

⦁ Photo-bioelectrochemical cells: This is an entirely new idea for solar cells. The idea is to use the biochemical process of microbes, enzymes, and plants to enhance cell efficiency. This cell’s working principle is described in papers from the Hebrew University of Israel and the University of Bochum, Germany. But to unite photosystems with enzymes is a real challenge. [mit.edu]

⦁ Floating Solar cells: as the traditional silicon-powered solar cells are getting cheaper and more efficient, scientists proposed a floating solar farm on water bodies. The study suggests that floating PV cells can generate a tremendous amount of electricity. The cooling effect from water can increase power generation by up to 10% more than normal land-based cells. But the maintenance is a bit costly. A floating solar power plan already exists in California at Napa Valley.

⦁ Solar Fabric: Researchers are trying to create a solar fabric that can produce solar power on the go. The main idea is to use solar radiation everywhere since it is available around. The material will use photovoltaic treads. Another project is to combine PV panels with solar fabric. Solar material may be used to charge phones on the go or even keep the cloth warm in winter. [mit.edu]

⦁ Concentrated solar sunray: Today, solar cells can only utilize up to 40% of the sunray. But a focused beam of solar rays can technically increase the efficiency of the cells. The rays can be concentrated by mirroring the rays toward the panels. Numerous companies like IBM and others have already tested this technology. It promises great potential.

Conclusion

We have made a workable comparison of the standard 12 volts solar power systems and 24 volts systems. We found that the 24 volts systems surpass the traditional systems thinning a thin margin from the discussion.

The main advantage 24 volts system has over the 12 volts system is its cost-effectiveness. Since both methods are commonly used for off-grid purposes, cost-effectiveness is a real issue.

Moreover, 24 volts system produces a surplus which can be stored to use later. The traditional 12 volts system is more compatible with small appliances, but a simple inverter can step down the house’s voltage. So, this cannot be considered a significant advantage. Also, the traditional systems can not produce as much as 24 volts systems. All in all, the 24 volts system should be the better choice.

Even a few years back, solar panels were not that much popular as it is today. But the usage and awareness spread made it a reliable source of off-grid power. Today, 24 volts system holds more potential than the traditional 12 volts system.

So, users should be more aware of what they want and which system they should choose. The answer should be the 24 volts solar power systems.