Solar inverter types explained: string, hybrid, off-grid and micro-inverters

The solar panels on your roof get most of the attention, but the inverter does much of the thinking. It converts the panels' power into something your home can use, keeps the system in step with the grid, protects it when something goes wrong, and often tells you through an app how much power you produced today.

Inverters also come in several types, and the right one depends on your roof, whether you want backup, and how much shade you have. This guide explains each type in plain language so you can follow what an installer is proposing and ask the right questions.

What every solar inverter does

Whatever the type, a solar inverter has four core jobs:

1. Convert DC to AC. Panels produce direct current; your appliances and the grid use alternating current.
2. Track the maximum power point. Panel output changes with sunlight and temperature. The inverter continuously adjusts to draw the most power the panels can give. This is called MPPT (maximum power point tracking).
3. Synchronise with the grid. In grid-connected systems, the inverter matches the grid's voltage and frequency so it can feed power safely.
4. Protect the system. It shuts down for faults, overvoltage or grid failure, and logs what happened.

The differences between types come from how they handle batteries, how many panels each unit manages, and where they sit in the system.

1. String inverters (grid-tied)

A string inverter is the most common type on Indian rooftops. Panels are connected in series into one or more "strings", and the strings run to a single inverter box, usually mounted on a wall near your distribution board.

How it works: the inverter converts the combined DC from the strings into AC for your home. Surplus power is exported to the grid through your net meter.

Strengths:

• Lowest cost per kW of the main options.
• Simple, proven and easy to service, because there is one box to check.
• Good efficiency on unshaded roofs.

Limitations:

• Panels in a string affect each other. If one panel is heavily shaded or dirty, it can pull down the output of its whole string.
• No backup during power cuts: grid-tied inverters shut down when the grid fails.

Best for: most homes and businesses with reasonably open, unshaded roofs that mainly want to cut their electricity bill. This is the standard choice for an on-grid solar system.

Single-phase or three-phase?

String inverters come in single-phase and three-phase versions. The choice follows your electricity connection. Many larger homes and most businesses have three-phase supply, while smaller homes are often single-phase. Your DISCOM's rules on how much solar can connect to a single-phase supply also matter. The installer should check your connection and sanctioned load during the site visit.

Multiple MPPT inputs

Many string inverters have two or more MPPT inputs. This lets panels facing different directions, or with different shading, sit on separate strings that are optimised independently. It is a useful feature on roofs with more than one usable section.

2. Hybrid inverters

A hybrid inverter works with both the grid and batteries. It powers your home from solar, charges batteries with surplus, exports what is left, and switches to backup during a power cut.

Strengths:

• Backup for essential loads during outages.
• Store daytime solar for evening use.
• Keeps net metering for exported surplus (subject to DISCOM approval).

Limitations:

• Costs more than a string inverter.
• Needs batteries, which add significant cost and need replacing during the system's life.
• More settings to get right.

Best for: homes and businesses with frequent outages or critical loads. Our full guide to hybrid inverters explains how they decide where power goes and when they are worth it.

3. Off-grid inverters

An off-grid inverter runs a system with no grid connection at all. Everything comes from solar panels and batteries.

Strengths:

• Works where there is no reliable grid, such as remote farms or sites far from the network.
• Complete independence from the DISCOM.

Limitations:

• Needs a large, carefully sized battery bank.
• Cannot export surplus or use net metering.
• Generation must cover all your use, including cloudy stretches.

Best for: locations without a dependable grid. See our off-grid solar page for how these systems are designed.

4. Micro-inverters

A micro-inverter is a small inverter fitted behind each panel (or each pair of panels). Each panel produces AC independently, and the outputs are combined.

Strengths:

• Shade tolerance: one shaded or dirty panel affects only itself, not the whole string.
• Panel-level monitoring: you can see each panel's output and spot problems precisely.
• Flexible layouts: panels on different roof faces or angles work well together.
• Lower DC voltage on the roof, which some consider a safety advantage.

Limitations:

• Higher cost per kW than a string inverter.
• More electronics on the roof, exposed to heat. In hot climates like ours, quality and heat rating matter.
• A fault means accessing the roof, not just a wall-mounted box.

Best for: roofs with unavoidable shading, complex layouts with many small sections, or owners who want panel-level monitoring and accept the higher cost. On a simple open terrace, a string inverter usually gives better value.

5. Power optimisers (with a string inverter)

Power optimisers sit between micro-inverters and string inverters. A small optimiser is fitted to each panel, but it does not convert to AC. It conditions each panel's DC output so that a weak panel does not drag down the others, and a central string inverter does the conversion.

Strengths:

• Much of the shade tolerance and panel-level monitoring of micro-inverters.
• Conversion stays in one central inverter.

Limitations:

• Adds cost and roof electronics compared with a plain string system.
• Requires a compatible inverter.

Best for: shaded or complex roofs where you want panel-level optimisation but prefer a central inverter.

Central inverters (large commercial)

For very large systems, such as solar parks and big industrial rooftops, a few large central inverters handle huge arrays. They are not used on homes, and most commercial rooftops in our region use multiple string inverters instead, which gives some redundancy: if one inverter fails, the others keep working.

How to choose: a practical guide

Start with three questions.

1. Do you need backup during power cuts?

• No: grid-tied string inverter.
• Yes, and you have a grid connection: hybrid inverter with batteries.
• There is no reliable grid: off-grid inverter with batteries.

2. How much shade is on your roof?

• Little or none: string inverter.
• Some, but avoidable with good layout: string inverter with multiple MPPT inputs.
• Significant and unavoidable: consider optimisers or micro-inverters.

3. What is your connection?

• Single-phase or three-phase decides the inverter model, and your sanctioned load affects how big the system can be.

For most homes in Hyderabad and Anantapur with an open terrace and occasional outages, the answer is a grid-tied string inverter. For homes with frequent outages, it is a hybrid inverter.

Inverter sizing: matching the inverter to the panels

The inverter's AC rating is usually close to the panel array's DC rating, sometimes slightly lower, because panels rarely produce their full rated output in real conditions. A good installer sizes the inverter to the array, your connection and your DISCOM's rules, not just to a round number on a package.

Inverter lifespan and warranty

Inverters work hard and get warm, so they generally do not last as long as panels. Panels carry 25-year performance warranties; inverters typically carry 5 to 10 years. The inverters we install (Growatt, Solis and Goodwe) carry 5 to 10 years depending on the brand.

That means you may replace the inverter once during a 25-year system life. Factor it in when comparing quotes.

To help an inverter last:

• Install it in shade with good ventilation. Direct sun and poor airflow shorten its life.
• Keep it clean and dry, away from water and dust.
• Use proper surge protection. We install surge protection devices on both the DC and AC sides.
• Watch the monitoring app for errors or drops in output.

Monitoring: your early warning system

Most modern inverters come with Wi-Fi monitoring and an app. Use it. A sudden drop in daily output can point to a tripped breaker, a faulty connector, heavy dust or an inverter fault. Catching it early saves weeks of lost generation.

Our maintenance visits, scheduled every three months, include checking inverter logs and connections, and we commit to responding within 48 hours when a customer reports an issue. Our solar maintenance and AMC page explains what a visit covers.

Safety and protection around the inverter

The inverter is part of a larger protection system. A safe installation includes:

• DC and AC distribution boxes with the right breakers and fuses. We use Siemens or Finder DCDB and ACDB, with a 25A MCCB.
• Surge protection devices on both sides.
• Proper earthing, including a separate lightning-arrestor earth pit. See our guide to solar earthing and lightning protection.
• Correct cable sizes and quality connectors, so nothing overheats.

If a quote mentions only "inverter and panels", ask what protection is included.

Questions to ask about the inverter in your quote

1. What make and model, and what kW rating?
2. String, hybrid, off-grid or micro? Why that type for my roof?
3. How many MPPT inputs does it have?
4. Single-phase or three-phase, and does it match my connection?
5. What is the warranty, and who services it locally?
6. Where will it be installed, and will it be shaded and ventilated?
7. Does it include monitoring?

How Origian chooses an inverter for your system

We choose the inverter after the site visit, not before. We look at your connection, your roof's shading and layout, how often outages happen, and what you want the system to do. Most homes get a grid-tied string inverter; homes with frequent outages or critical loads get a hybrid system. Our quotation lists the exact model, the full price before any subsidy, and the warranty terms.

To get a recommendation for your roof, book a free site survey. For a broader view of costs, see our home solar cost guide.

Reading an inverter datasheet

When an installer names an inverter, you can look up its datasheet. These are the lines worth understanding:

• Rated AC output (kW): the continuous power it can deliver to your home and the grid.
• Maximum DC input (kWp): how much panel capacity it can accept. It is often a little higher than the AC rating, because panels rarely produce their full rated output.
• MPPT voltage range: the voltage window in which the inverter tracks the panels efficiently. The string design must keep panel voltage inside this window across the year.
• Number of MPPT inputs: how many independent strings it can optimise.
• Maximum efficiency and weighted efficiency: how much energy is lost in conversion. Weighted figures reflect real operating conditions better than the peak.
• Protection rating (IP rating): how well it resists dust and water. Higher is better for outdoor or semi-outdoor locations.
• Operating temperature range: important in our hot summers.
• Grid connection: single-phase or three-phase.
• Communication: Wi-Fi or other monitoring options.

You do not need to check every number yourself, but asking your installer to explain how the inverter matches your panels and roof is a good test of their design work.

Inverter sizing mistakes we see

• An inverter far too small for the array, which "clips" production on sunny days and wastes energy.
• An inverter far too large for the array, which costs more than necessary and runs less efficiently at low output.
• Strings outside the MPPT range, especially on cool mornings when panel voltage rises.
• A single-phase inverter on a three-phase connection, or the wrong phase balance on larger systems.
• No room for growth, when the owner already knows they will add panels later.

A good design avoids these from the start.

A note on price

Inverter prices depend on type, capacity, brand and features. String inverters are generally the most affordable per kW; hybrid inverters cost more because they handle batteries and backup; micro-inverters and optimisers cost more because there is electronics behind every panel. Origian quotes the full system price, including the inverter, before any subsidy. The PM Surya Ghar subsidy is paid only for systems installed by a DISCOM-registered vendor, and Origian Power is not a registered PM Surya Ghar vendor, so a system we install does not qualify for it. See our solar system prices.

Inverter efficiency figures, explained

Datasheets often show two efficiency figures, and they are easy to misread.

• Maximum efficiency is the best the inverter achieves at its most favourable operating point.
• Weighted efficiency (sometimes called European or CEC efficiency) averages performance across the range of loads an inverter actually sees during a day, from a weak morning sun to full noon output.

The weighted figure is the more useful one for comparing models, because your inverter spends much of the day below full output. In practice, modern string inverters from established brands differ only slightly on efficiency. Correct sizing, good ventilation and a design that keeps strings within the MPPT voltage window make a bigger difference to your yearly units than a fraction of a percent on the datasheet.

Where the inverter goes, and why it matters

Inverters dislike heat. An inverter mounted in direct afternoon sun on a west wall, or in a closed cupboard, runs hotter and may reduce its output to protect itself. That is called derating. Good placement:

• is shaded and well ventilated;
• is protected from direct rain, even if the inverter is weather-rated;
• is close enough to the panels to keep DC cable runs reasonable;
• is easy to reach for maintenance and for checking the display.

On rooftop installations in Telangana and Andhra Pradesh, where summer temperatures are high, placement is one of the simplest ways to protect inverter life and output.

Frequently asked questions

What are the types of solar inverters? The main types of solar inverters are string (on-grid) inverters, hybrid inverters, off-grid inverters, micro-inverters, and string inverters with power optimisers. Large plants use central inverters. Most Indian rooftop solar systems use a string inverter, or a hybrid inverter where battery backup during power cuts is needed.

Which solar inverter is best for home in India? For most Indian homes with reliable grid power, a good on-grid string solar inverter is the best value. Choose one sized to your panels, with two MPPT inputs if panels face different directions, a clear warranty and local service. Origian installs Growatt, Solis and Goodwe inverters, with 5 to 10 year warranties.

What size solar inverter do I need for my home? A solar inverter is usually sized close to the panel capacity, for example a 3 kW inverter for a 3 kW array, sometimes slightly smaller where the site suits it. Your connection also matters: three-phase connections usually take three-phase inverters. The installer should show the sizing on the single-line diagram.

What is the difference between a string solar inverter and a micro-inverter? A string solar inverter converts the power from a whole series of panels at once; a micro-inverter sits under each panel and converts its output individually. Micro-inverters handle shade and mixed orientations better but cost more per watt. On an unshaded Indian rooftop, a string inverter is usually the economical choice.

What is the difference between a home inverter and a solar inverter? A home inverter (UPS) charges batteries from the grid and runs loads during power cuts; it does not use solar power. A solar inverter converts DC from solar panels into AC for your home. A hybrid solar inverter does both: it runs on solar, charges batteries and provides backup.

How long does a solar inverter last? A good solar inverter typically lasts around ten years or more, which is less than the 25-year life of the panels, so most systems need one inverter replacement. Warranties on the inverters Origian installs are 5 to 10 years depending on the brand. Shade, ventilation and clean surroundings help an inverter last longer.

Do I need two MPPT inputs on my solar inverter? You need two or more MPPT inputs on a solar inverter when panels face different directions, sit at different tilts, or get shade at different times. Each MPPT tracks its own group of panels, so one group's shade or angle doesn't drag the other down. On a simple south-facing roof, one input may be enough.