String Vs Micro Inverters- An Absolute Comparison: 2021

String Vs Micro Inverters

Inverters are used to convert the current generated by your solar panel system to the type of current used in most home appliances.

There are primarily 3 types of solar inverters:

  • Grid-Tie Inverters
  • Off-Grid Inverters
  • Hybrid Inverters

Grid-tied inverters need to connect with a grid to function. So, these are used in less power cut regions. While, where there is more power cut, Off-grid inverters come into usage.

Hybrid ones are the combination of both on-grid and off-grid inverters and can be used in both high power cut areas or areas where there is a rare or very little power cut.

Further, there are 3 types of grid-tied Inverters: Micro, String, and, central inverters.

In this article, we will be discussing grid-tied String vs Micro inverters and comparing them.

What are Micro-Inverters?

Microinverters are a good solution for complicated installations that have solar panels facing different directions or are the installation in which solar panels are tilted at varying angles.

Micro Inverter
Micro Solar Inverter

Microinverter does all of the inverting at the panel level, it’s just DC power going in and AC power going out. These are module-level electronics so one is installed on each panel. 

Upsides

Microinverters are expendable so if you wanted to add additional panels in the future even if they don’t match the characteristics of the panels you have, you can just add another inverter and can expand your system as much as you want whereas, with string inverters, you do need to keep some types of panels.

Also, because of the panel-level conversion, if one or more panels are shaded or are performing on a lower level than the others, the performance of the remaining panels won’t be affected. 

Downsides

Although, Microinverters are becoming a popular choice for residential and utility installations. Systems with microinverters can be more efficient, but these often cost more than string inverters.

What are String-Inverters?

These inverters are connected in a long string.

In string inverters, you would wire multiple panels in a string or we can say in series into the inverter.

String Inverter
String Inverter

We can have multiple strings each going into its MPPT channel, so that string of panels is independently managed.

Upsides

An advantage of these inverters is that they are fairly easy to install. Also, String inverters tend to be the least expensive option for inverters.

In the case of string inverters, you can save on upfront equipment cost as these inverters can handle the energy produced from a row of 5-10 panels instead of 5-10 microinverters. However, the long-term costs associated with string inverters far outweigh the benefits.

Downsides

The downside of this is that if one of those panels in that string does have some shading issues, it can potentially bring down the power output of that string.

But, many of them now have multiple MPPT inputs so that it only affects that particular string and wouldn’t affect the other.

Due to the panels attached in the string, there is high-voltage electricity constantly flowing in the solar power system. That energy is converted at the end of the row of panels and not directly at the panel, this can be a major hazard that can even lead to fault or fire.

String Vs Micro Inverter

In String inverters, solar panels are linked together with “strings” or series. These strings are then connected to a single inverter.

On the other hand, in microinverters, each panel is connected with its inverter, and thus, wired in parallel.

String inverters and microinverters each have some advantages and disadvantages. Also, both are suitable for different kinds of PV installations.

Shading: 

Panels in string do not perform well in shading conditions. Since solar panels for string inverters are wired in series, then, if one solar panel’s output is affected, the entire series of solar panels are affected.

This can lead to a major issue if some part of a solar panel series is shaded for any part in a day.

String Vs Micro Inverter
Image source: solareviews.com

Cost: 

String inverters have the benefit of being a short-term cheaper solution due to the less equipment requirement as compared to microinverters.

Microinverters are costly in comparison to string inverters.

Warranty:

Generally, string inverters have a warranty period between 8 to12 years, whereas microinverters have a warranty of up to 25-years.

Maintenance:

Also, when it comes to system failure, it is quite difficult to detect which inverter stops working in the case of micro inverters. While it is much easier to replace a string inverter.  

Conclusion

While comparing string vs micro inverter, there are a few main factors you need to keep in mind, these are Efficiency, Size, Warranty, and Price of the inverters.

String inverters are becoming a popular alternative over central inverters in small installations generally smaller than 1 MW. String inverters perform well with power optimizers. 

Although microinverters are better in many terms when compared to string inverters, you need to install typically the same number of microinverters as there are solar panels in your system.

So, which inverter best suited you? Tell us in the comment section below and let everyone know.

Also, you can connect with us on Instagram @solar.funda to get the latest updates on solar news and technologies.

Keerti Bhatnagar

Keerti is a tech geek with a vision to save the environment. She is from Uttarakhand, India. And, She is currently pursuing her MCA from G.B. Pant University of Agriculture and Technology, Pantnagar.

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