How Do Off-grid Solar Systems Work?

Off-grid Solar Systems for house

The idea of running all your fancy electrical appliances without any electricity bills is thought-provoking, right?

With the increasing need to shift towards a more sustainable form of energy, various advanced technologies often confuse the consumers. When you consider looking into any solar-powered system, the very first question is, would you prefer an off-grid or on-grid solar system?

All solar-powered systems work on the same principle. They convert solar energy into DC power using the photovoltaic effect. This power can either be stored in a battery or converted into AC power to run our home appliances.

Although all of them do the same work, there are various kinds of solar technologies depending upon the type of system they use. The three major types of solar power systems are as below:

  • On-grid solar systems – They are tried to an electric grid.
  • Off-grid solar systems – They are stand-alone power systems.
  • Hybrid solar systems – They are connected to the grid and support battery storage as well.

Off-Grid Solar System

Going off-grid means 100% of your power requirements will be fulfilled by the sun or other sustainable energy sources!

An off-grid solar system requires battery storage as it is not connected to the electricity grid. They work independently and generate enough power to meet your daily requirement. These systems need to be designed appropriately to meet the energy requirement throughout the year and even during harsh winters.

An off-grid solar system resembles a large battery bank connected to enormous power generators and end-users of electricity. Technically, it is a system of transmissions and distribution lines.

The off-grid solar systems are also often known as stand-alone power systems (SAPS). They are self-sustaining and can fulfill the energy needs in areas where the power grid is not reachable. Hence, they are preferred more in a remote location. Such systems are much more expensive than on-grid systems as the cost of inverters and batteries is high.

The installation process can be costly, and they require specialized apparatus to operate. Off-grid solar technology is an ideal preference for small to medium-sized households with average power requirements.  

On a brighter note, the cost of batteries and inverters is going down rapidly as the market of solar technology is growing with time. Hence, off-grid solar systems are getting more popular in urban areas as well.

The off-grid solar system consists of solar panels, mounting structure, solar batteries, grid box, solar inverter, DC disconnect switch, solar charge controller, back-up generator, and balance of systems.

Vital Components of Off-grid Solar System

Off-grid solar system

Solar Panels: Modern solar panels are made up of numerous silicon photovoltaic cells. These PV cells generate direct current (DC) from sunlight. All the PV cells are connected and linked with adjacent panels using cables. Solar panels are linked together in strings to form a solar array. When sunbeams fall upon the solar panels, they convert solar energy into electrical energy and feed the batteries.

Solar batteries: Numerous batteries are connected with wires into a large power supply. In the absence of batteries, there will be no stored energy to power your appliances during the nighttime. This heavy dependence on batteries is one of the crucial reasons why this system is expensive.

Your batteries should be large enough to store solar energy for at least two days for maximum comfort. Deep cycle batteries are required for an off-grid solar system to withhold a large amount of energy. They are made up of thicker plates for regular deep discharging and recharging.

Off-grid solar inverter: An inverter converts the DC power that has been generated through the solar panels into AC, which is then used by our electric home appliances. The conversion occurs with a minimal time gap. On-grid and off-grid inverters are different in nature and performance. Unlike an on-grid inverter, the frequency of off-grid inverters is not required to match that of utility grid power.

Solar charge controller: The charge controller regulates the amount of energy sent to the batteries for optimum performance. It is one of the essential components in an off-grid solar system as it protects the batteries from any lifetime damages. It basically adjusts the charging of batteries and prevents them from overcharging. The solar charge controller determines the efficiency of the solar system.

DC disconnect switch: DC disconnect switch is positioned between the off-grid inverter and battery bank. This is an additional switch used to stop the flow of current between these two components. It is an integral part of an off-grid system and is used in troubleshooting, maintenance, and protection against the electric shot circuit.

Back-up generator: This is an optional component in your off-grid solar system. When your batteries are not accumulating enough energy to power your house, primarily due to bad weather, you will need a back-up generator. However, if you do not mind giving your electric appliance some free time, you don’t necessarily have to invest in a back-up generator.

Working mechanism of an off-grid solar system

After collecting and converting the solar energy to electrical energy, the solar panels send them to a solar inverter. Then the power is directly sent to a battery inverter. From here, the energy stored in the battery is distributed throughout your home to power your electric appliances.

If there is any excess energy created, it directly goes into the battery bank for storage. The power from the battery bank is used during the night or cloudy days.

What makes it an off-grid solar system?

An off-grid solar system has a battery. This makes it different from other solar technologies as they don’t technically require any battery for power storage. If you have an on-grid system, you will not need batteries to store power for emergencies.

Let us imagine you had awful weather for the past few days without any sun; at such times, your off-grid solar system will use the power stored in the batteries. However, if you have an on-grid solar-powered system, it will simply pull the electricity from power lines connected to it.

What are the various uses of an off-grid solar system?

Scalability is one of the most significant plus points of using solar power as the primary energy source. Likewise, an off-grid solar system works at all levels. It may either be used to charge your phone or power a big factory. The possibilities are never-ending!

Just make sure that you invest in a good battery and efficient solar charge controller. The size and volume of your batteries will depend upon the amount of energy you wish to generate. The same goes for solar panels!

The common uses of the off-grid solar systems are listed below:

  • Charging portable phones, tablets, and laptops
  • Generating electricity for RV
  • Running electrical appliances
  • Powering the appliances in small cabins or apartments
  • Powering medium-sized homes
  • Fuelling energy-conscious factories and companies

Pros and Cons of the off-grid solar system

Advantages

  • Freedom from utility bills. Say yes to a significant monthly saving!
  • Positive environmental impacts.
  • Grid failure will not affect your power supply. No blackouts due to thunder and lightning!
  • Encourages an energy-conscious lifestyle. Go 100% green!
  • Best for remote and underdeveloped locations where the electrical grid isn’t available.
  • Increase your home value. An entirely off-grid and independently powered home looks way more attractive!
  • Good return on investments (saves you a hefty amount of money in the long run!)
  • Sustainable form of energy that will last you decades!

Disadvantages

  • Upfront costs can be very high and intimidating for homeowners.
  • Installation can be time-consuming.
  • It might be illegal depending upon where you live.
  • No back-up power source when the weather goes haywire for an extended period.
  • Surplus energy production that could go to waste.
  • Batteries may degrade rapidly if you are heavily dependent on off-grid energy.

Is going off-grid right for you?

Well, if you live away from electricity grids, you don’t exactly have a choice. However, as an urban dweller, if you think of going 100% sustainable, you might want to analyze its pros and cons beforehand.

Solar energy is one of the cleanest and best forms of energy, no doubt! But depending upon your location and house size, you might want to estimate your monthly power consumption accurately. And, then if you see fit, get yourself an off-grid solar system!

Lastly, it would be wise to say that one system isn’t always better than the other. It all depends upon your needs and the situation.