Micro Inverter VS String Inverter: What to Pick & Why?

Micro Inverter vs String Inverter: A solar inverter is an electric current converter, which converts the direct current, coming from the solar panel to the alternate current, which is used to run all our home appliances and other electric appliances. The solar panel is charged with solar energy that acts as DC output of solar panels. There are mainly five types of solar inverter

  • String inverter
  • Central inverter
  • Micro inverter
  • Hybrid inverter
  • Battery inverter.

String inverter and Micro inverter, both of them convert DC to AC. But the basic difference lies in their configurations. In the Micro inverter, the converter is installed on the back of each solar panel. In the case of a string inverter, the converter is set up at the ground level.

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    What is a Micro Inverter?

    Micro inverter is a miniature version of a solar inverter. The main functionality is the same as a solar inverter i.e. converts the incoming DC from solar panel to AC.

    Key features:

    • Each panel has a separate converter device, installed at the back of the panel.
    •  The power ratings of this inverter are 250W and 500W for 1 and 2 PV modules respectively for residential purposes. 1KW micro inverter is also available for commercial purposes.
    • Mostly used are single phase for residential purpose and three phases for commercial.
    • Each PV module has its own MPPT.
    • Their efficiencies are not compromised due to their orientations or configurations.
    • The output of each inverter can be monitored separately.
    • If one panel gets shadowed then it will not affect the functionality of other panels.
    • All panels remain as AC units, so there are no high voltage units on the roof.
    • You can expand your system in future as per your requirement.
    • The longevity of this inverter is higher.
    • The cost of the micro inverter is on the higher side.
    • If the inverter is exposed to higher temperatures, it’s longevity can be hampered.

    What is a String Inverter?

    A string inverter also serves the same purpose. The solar panels are attached in an array and each array has its string inverter that is mounted on the wall.  This inverter converts the DC input to AC output for our different consumptions.

    Key Features:

    • All the solar panels have to be placed at the same angle and facing the same direction.
    • All the panels are used in a single string, should be of the same type.
    • This inverter can be in three phases.
    • The efficiency of this inverter is high.
    • This inverter can be controlled by a remote.
    • The installation charge of this inverter is budget-friendly.
    • As you can install it on a large scale without much expense,  it is valuable for commercial usage.
    • The maintenance is easier and also inexpensive.
    • As this inverter is used for decades, it finds to be more reliable.
    • If one panel malfunctions, then it will affect the entire panel of the same string.
    • If all panels don’t get direct sunlight,then it will drop their production of electricity.

    Micro Inverter Vs String Inverter Differences

    Micro and string both these inverters’ working functions are the same but still they have some differences in their efficiency, cost and many other things. These are listed below. Check this section for Micro Inverter vs String Inverter.

    • Safety:  In case of a string inverter, the conversion of DC to AC, is done in the inverter which is mounted on the wall. So the panel remains high voltage DC. But in a micro inverter, as the inverter is designed on the back of the panel, the conversion is done then and there. So it has alternate current, which is much safer than a string inverter system.
    • Production:  In a micro inverter, all panels have a separate inverter. So if one panel gets damaged or shadowed then it will not affect the other panels. But in case of a string inverter, the whole string of panels is connected and has one inverter. So if one panel gets shaded, its production is dropped. This will affect the entire string of panels connected to it. As a result, the whole production is reduced to some extent. So a micro inverter is a better option from this viewpoint.
    • The direction of Installation:  Each panel acts as an individual inverter in a micro inverter system.  So you can place it in different directions on your roof. But in a string inverter, the panel’s string should be placed in the same direction with the same type. If the direction of installation is changed, we need to install another string inverter. For example, suppose you place the panels in south and east directions on the roof, then there will be two different inverters for both the directions.
    • Cost:  The cost of a micro inverter is generally higher than a string inverter. The price of string may be one-third of the micro inverter. If your budget is within a limit then string inverters will be affordable for you.
    • Maintenance:  If you own a micro inverter then the maintenance of it will be more hectic. As the inverter is installed under the panel, which is mounted on the roof. So when the inverter malfunctions, you have to climb up and fix it. Whereas the string inverter is connected with the panel through a wire-stag and it is mounted on the wall. So it is easier to approach the inverter when it needs to be repaired or replaced.   
    • Reliability: String inverter is used for decades. So people find it more convenient. Electricians are well known about their parts and backups. But the micro inverter is comparatively newer. Manufacturers are still working on it and trying to find out its different working conditions. So people opt for string inverters more.
    • Warranty: The most recommended manufacturing company of the micro inverter gives 25 years of warranty. Whereas the string inverter’s manufacturers give only 10 years of warranty on it. So people are likely to invest in such products which have higher warranties.

    How to Pick the Best Inverter for Your System:

    Nowadays a wide range of solar inverters is available to us. There are few things that we have to keep in mind before shop for an inverter. Here is the list.

    Efficiency: The efficiency of a solar inverter means how much DC coming from a solar panel is converted to AC. This is a major factor while purchasing an inverter. So more the efficiency of the inverter, the more output you get for daily usage.

    Warranty: Solar inverters are a bit expensive. So you have to check the warranty period before buying it. Some come with 10 years of warranty while some give 15 years.

    Output Waveform: The output waveform of an inverter is of various kinds such as sine wave, modified sine wave, etc. The sine wave is more efficient for powering any device. So check this factor whether your inverter produced sine waves or not.

    Price:  Budget is an important factor that you can’t avoid while purchasing anything. String inverters are inexpensive compared to micro inverters. So you can purchase any of these inverters according to your budget.

    Battery Capacity: A valuable inverter should come with a high battery backup. The unit of measurement is Ampere Hour (Ah). The batteries can be segregated into three categories- flat plate batteries, tubular batteries, maintenance-free batteries.

    Frequently Asked Questions

    The micro inverter of the most popular brand provides 20 to 25 years of warranty. For most of the cases, this figure may vary i.e. 10 or 15 years. But after several years some parts may break down and need replacement. Sometimes it’s efficiency may also decrease. This will entirely depend on the manufacturing company.

    Now people are looking for cost effective inverters for future usage and also moving towards renewable energy sources. The string inverters have a high yield of electricity. So it can grab the market as one of the most usable renewable energy resources.

    As solar inverters cost a good amount it’s a common question among the people. Most of the solar inverters’ life span is about 10 to 15 years. It depends on certain factors such as maintenance, manufacturing company, weather conditions.

    Conclusion

    As the non-renewable energy sources have been disappearing gradually, it’s high time to switch to renewable energy sources. The most popular and easily available renewable source is solar energy. With the advancement of science, we have few kinds of solar inverters which convert solar energy to our usable energy sources. 

    In this article, we have discussed micro inverter vs string inverter in detail. Both of them are efficient along with their own set of pros and cons which are also discussed here. Hope that this article will be helpful to you to choose better renewable energy sources for a sustainable future.

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