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Solar Inverter Price in India

The inverter is the heart of any Solar PV system. It converts DC (generated from Solar Panels) to AC Current (needed by appliances and the grid), and it also controls and monitors the entire PV System. It ensures that the Solar PV modules always operate at their radiation and temperature-dependent maximum power, and it also makes sure that the grid is safe. So while buying a Solar PV system, it is essential to choose the right inverter for the safety and efficient functioning of your system.

We are seeing that there is a growing interest in buying Solar PV Systems in India. While Bijli Bachao has written several articles on basics of Solar PV installation, we are now beginning to write on the more practical aspects of installing Solar PV in India. In this post, we will cover a few basics about Solar Inverters very importantly on their price in India.

The type of inverter that you have to install depends on the type of Solar PV System that you implement. So let’s first look at different types of solar PV systems that are there.

Ideal Solar Panel System Type for your home

There are two types of Solar Panels Systems:

• Off-Grid Solar Panel System:

This type of system is ideal when you have regular power cuts in your house, and you are looking for a power backup solution. This system consists of a Solar Panel, MPPT Charge Controller, Inverter and a battery bank. The role of a Solar Panel is to convert light into energy (or electricity). The Charge Controller makes sure that the right amount of electric current is generated and passed on to the battery. This prevents any damage to the batteries. The batteries are the storage tank that store all the energy or electricity generated. The inverter is like a car engine, which helps run the appliances by taking electricity stored in the batteries.

As this system comes with a battery, it can be used whenever there is no electricity. You can also get solar hybrid inverters that can charge the batteries when sunlight is there and charge them from the grid when the sunlight is not enough.

As this system involves batteries and storage, this system is costly and also requires regular maintenance of batteries. The batteries need a change every 4-6 years depending on how well they are maintained.

Check on the sizing section below to calculate the right size of system for you.

• Grid Connected Solar Panel System:

If your purpose of implementing solar is to reduce your electricity bill, then a grid-connected system is an ideal system. In a grid-connected system, there are no batteries. The electricity generated is used in your house. If extra is produced, then it is sold to your electricity distribution company. If your electricity consumption is more than the production from the solar panels, then it is compensated by the grid. This system has an inverter and a net-meter.

This system is not good if you have regular power cuts. That is because it goes down as the grid fails. So if your system is generating electricity and the grid fails, then the electricity generated is wasted.

Check on the sizing section below to calculate the right size of system for you.

Sizing a Solar Panel System

Sizing of a solar panel system depends on the type of system that you are going for. Let us look at the two types:

1) Off- Grid System

To get the right size of solar panel system for your off-grid needs, you need to look at the appliances that you want to run and the number of hours you want to run them. This is because you need to understand the size and type of batteries that you need to store the electricity that you need and also the size of panels that can generate sufficient electricity. We have prepared a calculator that you can use to calculate your solar-inverter-battery requirements. This calculator can only help you to calculate Off-Grid Solar Panel requirements. To use it, use the steps mentioned below:

• Add all the appliances that you have in the calculator. You can always change the wattage if you know it is different from what is mentioned in the calculator. You can use the “Add Appliance” button at the bottom to keep adding more appliances. To remove an appliance, press the “X” at the end of each row.
• The list of appliances in the calculator is based on some of the most common appliances that we get queries on. If you do not find your appliance on the list, you can select “Custom” at the end and add your own appliance.
• Press the “Calculate” button at the bottom to get the calculation. Do tick the “Calculate Solar Panel Requirement” checkbox if you want to do calculations for Solar Panels.
• You can also print the output if you want.
• Please note that this calculator is good for a regular home setup or for a small requirement. It will not work well for big commercial or industrial setups.

2) On-Grid System

To size an on-grid system, you need to look at your electricity bills. There are two numbers that are important: One is your maximum monthly consumption throughout the year, the other is your connected or sanctioned load. A 1 kWp Solar Panel System can generate about four units of electricity per day (roughly). It can be more or less, depending on the sunlight. Take your maximum monthly consumption and divide it by 120 (4 x 30 … 4 units for 30 days). You will get the number of kWs that you need to bring down your electricity bills to zero. Please note that your panel size cannot exceed more than 150% of your connected load (100% in some states).

Type of Solar Inverters

After you have finalized the type of Solar PV system for your house, the next thing that you need to look at is the type of Solar Inverters that are available. Let’s look at different kinds of solar inverter that are there for different Solar Panel Systems:

Grid Connected Inverters

There are 3 types of grid connected inverters that you will find in the market:

1. String Inverters: These inverters are connected to an array of solar panels and their output depends on the output of the worst performing solar panel. So if say you have 10 panels connected in a string and one of them has a shadow on it, the output of that panel will go down and with a string inverter, the output of the whole system will go down because they are all connected in a string. A string inverter should be used only if you have a complete shadow free area. From a price perspective, these are the cheapest. However, the price also varies with brand.
2. Inverters with Solar Optimizers: In this setup there are optimizers usually connected with two panels and the output of the string is optimized so that the system output does not go down because of shadow on a few panels. This setup is slightly expensive as compared to string inverters, but is quite good if you do not have a complete shadow free area.
3. Micro Inverters: In this kind of system instead of one string inverter, there are multiple micro inverters connected to one or more panels and the system is optimized to have maximum output. This is also good when you do not have a complete shadow free area. The output can be more than inverters with solar optimizers but these are really expensive.

Off Grid Inverters

If you want an off grid inverter then there are two types of off grid inverters:

1. Solar Off Grid Inverter: A regular solar off grid inverter will just work with Solar Panels. As in, it will charge the battery only with power generated through solar panels. This type of system is good if you want to live completely off-grid. Or you are at a place where there is no electricity supply.
2. Solar Hybrid Off Grid Inverter: This type of inverter will have a facility to charge the battery from the grid or from solar. It will charge the batteries from solar if there is sufficient generation from Solar. If the generation is not enough then it will charge the batteries from the grid.

Within Off Grid you will also hear about PWM (Pulse Width Modulation) and MPPT (Maximum Power Point Tracking) systems. These are different charge control technologies that prevent damage to your batteries due to overcharging. MPPT is better and efficient technology but is more expensive as well. It is ideal to go for MPPT if you are going for larger installations. In smaller installations, if you want to save on costs then PWM can also be used.

You may also hear about Hybrid On Grid – Off Grid systems which can send the electricity to the distribution company when the grid power is on and can charge batteries during power cuts. Right now, we do not have much information about these and thus we will not cover them in detail.

While buying a Solar Inverter here are a few basic things that you should look at:

The efficiency of the Inverter

Your solar panels may generate some amount of electricity, but all of it does not get converted to useful electricity. Some of it is lost because of the efficiency of the inverter. So the more efficient the inverter is, the more electricity will be converted to useful electricity. As per our research, we found that Grid Connected inverters have efficiency as high as 99% with the most common ones having efficiency higher than 97%. In the case of Off-Grid inverters, we found that the efficiencies range between 82 to 87%. So do buy an inverter with higher efficiency to get more electricity output.

Ingress Protection

Ingress protection rating or IP rating is a rating that any appliance has which certifies how good the appliance is protected from dirt or humidity. You may see IP65, IP66, IP67, or some other IP number mentioned on the inverter (more details on this link). The higher the number, the better is the protection. However, you may not need the highest protection as a number like IP67 is required only when an appliance is submerged in water (read more on Wikipedia). A number like IP65 is good enough to protect from dust and rain.

Anti-Islanding protection for Grid-Connected Inverters

In the case of grid-connected inverters, the most important protection required is Anti-Islanding protection. This makes sure that in case of power failure of the grid, your solar PV system is not sending electricity generated by your system to the grid. This is to protect engineers working on the grid to fix it during power failures. Your grid-connected system will not get approval to connect to the grid till your inverter has this feature.

Additional features to be checked for grid-connected inverters

While buying a grid-tied inverter, make sure that it has good surge protection, overcurrent protection, has PV array string fault monitoring and also data logging and display features. A good inverter will have software that can help you monitor the power generated by your PV system and also check the health of your PV system, along with protecting your system from surges and overcurrent.

Features to be checked for Off-Grid inverters

Choosing an off-grid inverter is very similar to choosing a regular power inverter. You have to make sure that it has a good battery management system to make sure that it does not overcharge the batteries, has a temperature control system to prevent overheating of the battery (overheating can shorten battery life), prevents over current, etc.

Wave Form of an Inverter

It is very important that you choose an inverter with the right waveform. A pure Sine Wave inverter is always the best for your appliances. Avoid going for a Square wave or modified sine wave inverter. The cost of a sine wave inverter is comparable to others.

Warranties

Based on our observation we have found that you can get up to 5 years warranty on a Grid-Tied inverter, whereas off-grid inverters are available only for 1-2 year warranty. If you go for a really good brand inverter in case of a grid-tied inverter, it will be as good as “fit it and forget it”, as the maintenance required for inverters is minimal.

Price of various Solar Inverters in India

We have collected some data from some of the e-commerce sites selling solar inverters and the data is mentioned below:

Solar Inverters

Some Off-Gird Inverters in India