If you are looking to buy solar inverters but are unsure how to do it, you are certainly at the right place. You will find here a simple, precise explanation of what an inverter is, what it does, and why it is needed, along with other vital pieces of information.
Solar inverters are complicated devices, yet the system will not function correctly without one. Unfortunately, this also makes it the part that is likely to have maintenance issues since they are located near the solar panels – enduring harsh, all-weather conditions. That is why investing in a high-quality inverter that can function smoothly without problems is essential.
What are Solar Inverters?
An inverter is a device that converts direct current electricity (DC) to alternating current electricity (AC).
A solar inverter does the same thing, except it converts the DC electricity generated from the solar panels.
In direct current, electricity flows only in one direction; as a result, a constant voltage is maintained throughout. In alternating current, electricity flows in both directions – changing its course from positive to negative with time. Therefore, the voltage also varies with time.
Now, why does it matter? Because all our electrical appliances run on AC. Everything in your home, office, and elsewhere in the world requires AC power.
The same is mentioned in the rating on any electrical component – something along the lines of ‘100 – 200 V, 50-60Hz, 0.5A.’ That is nothing but the specifications of the input electricity your device needs to function – voltage needs to vary from 100 to 240 volts, a frequency of 50 to 50 hertz, and a current of 0.5 amperes. Therefore, the function of an inverter is to regulate the flow of electricity.
Solar inverters are needed to convert the DC electricity into usable and universal AC. Unfortunately, there is not a lot you can do with DC output – you can store them in your batteries, but at some point, you will still need an inverter to convert that energy into the usable form.
Cost of Solar Inverters
Solar inverters may cost anywhere between Rs.5,000 to Rs. 1,50,000 and more. The price depends mainly on the type of inverter, your solar power system, and power requirements. Things like brand considerations, warranty, and customer service also play a role.
Functions of a Solar Inverter
Depending on the kind of solar power set-up you have for your home or business, your inverter will have one or more roles to fulfil.
On-Grid System
On-Grid or grid-tie is the most commonly used solar system. They do not need batteries to work and have plenty of customer benefits. The DC from the solar panels is converted into AC by the inverter – which is then fed to your appliances, and the extra power is fed to the public electricity grid. Similarly, when you need more power and your photo-voltaic cells are not functioning, you take the energy from the grid, and the balance is settled through net metering.
In case of a blackout, the system will stop functioning. This is because if the inverter is still supplying electricity to the grid, it may cause a safety hazard for the repairperson fixing the lines.
The solar inverter in a grid-tie system essentially manages the flow of current in such a way that it:
- Meets your energy demands
- Sends the excess energy to the utility grid
- Draws electricity from the grid when the panels are not operating (rainy days, nighttime)
- Matches the AC specifications of the grid (voltage, frequency)
- Automatically shuts down when the utility is off (due to blackouts, weather damage, shutdown, maintenance)
Off-Grid System
Within off-grid systems, the idea is to be completely independent of the grid and meet the energy demands yourself. This includes using batteries to store the power from the rooftop solar panels and cells – and then using this battery power to supply electricity when the panels are not operational.
As a result, the system is also more expensive due to more components. But it is an investment worth making if you experience frequent blackouts and electricity issues.
The role of a solar inverter here, therefore, is to simply:
- Convert the DC battery/solar power into AC
The battery is charged via the photo-voltaic cells in your panels. A device known as a charge controller is used to control the flow of current. It is not like an inverter; its role is to ensure that the batteries are not overcharged by serving as a safety backstop. Many inverters in the markets these days have in-built charge controllers.
Hybrid System
As you know, hybrid systems take the best of both worlds. They can store energy into batteries, meet your home power requirements, and supply excess electricity to the grid; conversely, they can take in energy from the grid to meet the downtime demand and charge the depleted batteries.
This happens with the help of an inverter charger – which essentially converts the AC from the utility/grid side into DC to charge the battery.
This system employs hybrid inverters which are bi-directional in nature:
- Manage the flow of AC output from the converted DC into your home and grid
- Regulate the current from solar panels into batteries (through DC coupling/charge controllers)
- Meet the technical power specifications of the grid (voltage, frequency, etc.)
- Use the AC input from the grid to charge the battery
- Use the AC input from the grid to meet your home/business’s energy demands (when the panels are not operational and batteries are depleted)
Types of Solar Inverters
When you buy solar inverters in India, you will find several types of inverters to choose. Each has its advantages and disadvantages and considers fundamental factors like budget, efficiency, design, compatibility, storage, et cetera.
String (Central) Inverters
String inverters, also referred to as central inverters, are the most common type of solar inverters you will find on the market. This is because they have been around for quite some time and are often reliable, requiring little maintenance.
With string inverters, all solar panels are connected to one centralised inverter – which then converts the total DC output of the PV cells into AC.
| Pros | Cons |
| Least expensive | Individual panel-level monitoring is not possible |
| Reliable, trustworthy | If one panel stops working, the output of the entire system goes down |
| Easy to maintain since one centralised unit handles the entire load | Not feasible if solar panels are facing different directions |
| Supports overall system-level monitoring |
String Inverters with Power Optimizers
One way to iron out the kinks in the central inverters is using power optimisers.
These are devices that are placed at the bottom of every solar panel. They fine-tune the DC current generated by the PV cells and optimise it before sending it to the inverter. This way, the job of the string inverter becomes easy. As a result, the efficiency is also higher, and power losses are minimal.
Power optimisers also enable monitoring every panel individually and troubleshoot the issues easily.
| Pros | Cons |
| They can decrease the impact of shading/damage on individual solar panels | More expensive |
| The output of the system does not go down if one panel stops working | Maintainance and repair may be difficult depending on the placement of the panels |
| Supports panel-level monitoring and diagnostics | |
| More efficient than string inverters |
Microinverters
Microinverters are the next step in the evolution of solar inverters. They are a bit like power optimisers because they individually connect to every solar panel in the array and convert the DC into AC right there and then.
In other words, every panel in the solar power system has its own inverter. This way, if one panel stops working, the system’s output does not take a hit.
| Pros | Cons |
| They decrease the impact of shading/damage on individual solar panels | Most expensive among the bunch |
| The output of the system does not go down if one panel stops working | Maintainance and repair may be difficult depending on the placement of the panels |
| Allows panel-level monitoring and diagnostics | |
| More efficient than string inverters | |
| Easy to increase the power output of the system without needing extra central inverters |
Hybrid Inverters
Hybrid inverters are becoming quite popular in India as they deliver the best on-grid and off-grid solar power systems. They allow you to store energy in batteries and export the extra amount to the grid. Moreover, it can work with and without the grid – thus giving you an uninterrupted power supply.
These inverters come with in-built charge controllers and inverter chargers. Unfortunately, they are also the most expensive of all solar inverters, but it is an investment worth making if you want to be truly grid-independent.
Things to Consider when Buying Solar Inverters
Now that you know a bit about what a solar inverter is and what it does, let us look at the things to look into make when it comes to buying one.
- Efficiency and Manufacturer’s Warranty
Obviously, no electrical device is 100% efficient. Therefore, when purchasing a solar inverter, you want to pick a device with the highest efficiency. The industry standard is upwards of 90%, and you may benefit from exploring your options to see which brands offer the most efficient inverter.
With that, you may also want to consider the warranty offered – which may vary from 1 to 5 years.
- Inverter Rating
The second thing you must consider is the technical specifications of the solar inverter. We are referring to metrics like total power output it can support, feed-in phase, peak current rating, input voltage, output voltage, frequency, et cetera. Ideally, you want to ensure that your inverter can support your PV panel system.
If you are looking at a 5 kW system, you need an inverter rating of at least that much capacity. As a rule of thumb, we suggest going with a higher-rating inverter to account for transmission losses from the solar panels.
- Safety Standards
Inverters are complicated devices, and we need them to operate as smoothly as possible. For this reason, it makes sense to go with an inverter from a reputed brand that follows strict safety standards and protective measures. It should offer internal protection from surges in power, lightning, or other hazards. Similarly, the circuitry should be intelligent enough to protect the inverter and the surroundings.
Parting Thoughts
A solar inverter is the system’s heart; it is worth investing time and money to get it right. Brands in India offer different types of solar inverters – best suiting your power requirements. On-grid, off-grid, or hybrid – you will find inverters for all solar power systems to fulfil energy demands and go green.