Do you know the answer? What does the Fronius Symo range of 3-phase solar inverters have that no other 3-phase solar inverters have? Well, you’re about to find out.

Solar and 3-phase power supplies don’t necessarily go hand in hand on the smaller scale, unlike larger scale installations. However, when a 3-phase solar power supply is a must, one requires a reliable solar inverter option to safely handle the higher voltage between phases while adequately managing the increased loads often drawn from a 3-phase supply. 

What Fronius inverter do you require? The Fronius Symo is the three-phase inverter by Fronius for systems rated at 3kW to 20kW.

  • Single-phase 1 – 3kW, Fronius Galvo >
  • Single-phase 1 – 15kW, Fronius Primo > 
  • Three-phase, 3 – 20kW, Fronius Symo > (You are here)
  • Three-phase, 25 – 27kW, Fronius Eco >
How to know if you have a single phase or 3-phase power supply? > 


Fronius Primo Solar Inverter - Solar Review

The Fronius Symo’s overall design is very similar to that of its single phase sister, the Fronius Primo. A highly efficient transformerless design built to accomodate an exceptionally wide variety of solar array formations with two maximum power point trackers (MPPTs). 

What must be noted, is Fronius Symo’s SuperFlex design (voltage and current window) when compared to the Fronius Primo isn’t as flexible for 3-8kW models due to the minimum DC voltage. The range though is still extraordinary when compared to competing 3-phase inverter options. 

10kW Fronius Symo models and above are designed with a larger current window to facilitate the connection of parallel strings.

Battery Design.

Although not essential for the connection of a battery, the Fronius Symo range of solar inverters has a hybrid solar and battery (multi mode) variant available. As with any hybrid solar inverter the battery compatibility is limited. Therefore it’s always best not to plan for the battery if you don’t know what battery you intend to get. Just know the options available and save your money in the short term.

Option A 

Battery: Fronius Symo Hybrid & Fronius Battery or LG Chem (DC Coupled).

Connection: The Fronius Symo Hybrid has an addition battery input with direct compatibility of the Fronius Battery. As of 2018  the LG Chem RESUH range is also compatible with the Fronius Symo Hybrid via the Fronius Check Box. 

A Fronius Smart Meter is required within the same distribution board as to which the Fronius Symo Hybrid is connected for battery charge and discharge.  

Option B 

Battery: Tesla PowerWall 2 (AC Coupled).

Connection: The Tesla Powerwall 2 with 13kWh of storage has a single phase 5kW inverter inbuilt. To accurately cover 3-phases, you’re going to need three Tesla Powerwall 2’s. 

Alternatively, one Tesla Powerwall 2 can export energy units in order to offset the units being imported on the phases of which the Tesla Powerwall 2 is not on. Certain electricity supplies around the world have rules around phase imbalance. Therefore, this method may not be an option.

Note: AC coupling increases a dwellings total inverter capacity, . Certain grid connection parameters in different regions will limit the maximum inverter capacity of a property depending on the grid, therefore, this method may not be for all.

Option C

Battery: SolarWatt Matrix (DC Coupled).

Connection: One string of the solar array is wired directly into the SolarWatt Matrix BMU (battery management unit). Then from the SolarWatt BMU the Fronius Symo is connected via the DC input. A communications gateway is required at the distribution board for intelligent battery charge and discharge control. The result is an evenly distributed 3-phase battery supply.

Note: This connection method does not have an option to provide an emergency power supply in the event of a power failure.

Download the Fronius Symo datasheet here:


Fronius Symo Solar Inverter Display - Solar Review

The most noteworthy feature within the Fronius Symo models are without a doubt the vast set of design options for ease of installation towards both installer and end user alike. Including a hybrid option, Fronius Symo Hybrid 3 / 4 / 5.0-3-S, Fronius cater for 3-phase power supplies unlike any other string inverter manufacturer.

Other notable key features include:

  • Dual MPPTs.
  • Large graphic display.
  • LED signalling.
  • Extra broad MPPT voltage & current window.
  • Dynamic Peak Manager: MPPT shade management.
  • Easy installation.
  • DC isolator built in.
  • WiFi monitoring inbuilt.
  • Remote monitoring.
  • Smart Grid Ready.

There is a lot to like about the Fronius Symo for 3-phase power supplies. The question ahead, where to next in the features department? Maybe a third MPPT in 10-20kW Fronius Symo models? Dual MPPTs within the Fronius Symo Hybrid would be nice. At this stage it’s the competition playing catch up with easily the most versatile 3-phase solar inverter in the Fronius Symo.


Above average european efficiencies, the Fronius Symo will endure environmental conditions ranging between -25oC to +60oC (-13oF to +140oF) with a 100% permitted humidity. The Fronius Symo performance will begin to derate when operating in air temperatures greater than 40oC (140oF) in nearly all models.

An IP66 protection rating ensures the Fronius Symo is able to be located both indoor and outdoors, although it’s always advisable to avoid direct sunlight to ensure a longer life expectancy and optimum performance. Cooling is regulated, therefore, an internal fan is present. Weight ranges between the different fronius Symo model ranging from 20kg up to 43kg (44 lb – 94.7 lb).

Average Inverter 95%
Fronius Symo (avg) 97%
Fronius Symo Hybrid 96%

Above: Solar inverter European efficiency.


Fronius Symo - Solar Review

As with the Fronius Primo, the base Fronius Symo inverter guarantee is a 5-year parts and labor warranty. Expandable warranty options are available for purchase through Fronius, however, cost and availability will vary depending on the country of which the installation occurs.

The most common warranty upgrade is the additional 5-year parts only warranty. Certain regions around the world such as Australia have enjoyed a complimentary offering of this upgrade (via redemption) for the last 2 to 3-years. 

Be warned, additional costs under these particular warranty upgrades will still see the consumer out of pocket for both shipping and labour in the event of a warranty claim.

Average Inverter (base)
Fronius Symo (base)
SolarEdge (base)

Above: Base manufacturer warranty on a scale of 12-years. (Longest central inverter base manufacturer warranty).

Tech Insight: Fronius Symo inverters like near all standard string inverters contain electrolytic capacitors. Often the first point of failure (if installed in a protected and well-ventilated area) for many string inverters. Generally speaking, the service life for electrolytic capacitors within solar inverters is often between 5 to 10 years.


Fronius Solar.web cloud-based remote monitoring software is a cut above most other manufacturer supplied monitoring options. Once commissioned and configured (a vital element which should be completed by the installer) an end user gains access to expanded features:

  • Basic live energy production.
  • In-Depth production analysis.
  • Historical data logging.
  • System savings in monetary value.
  • CO2 savings.
  • Programmable automatic reporting features.
  • Advanced email warning and notification system (including energy fluctuations, system dropouts, earth fault alarms).
    Assign alternative users and administrators.

The Fronius Solar.web solar monitoring portal is one of the most progressive available. It takes a good investment to develop great software and Fronius are providing insightful tools for installers and consumers alike. Apple and Android versions of Solar.web appear to be evolving although are severely lacking in exceptional features incorporated from the browser based login.

Mobile Applications are without a doubt the future of solar inverter interaction. Ignoring this key feature could leave one exceptionally underwhelmed with less insight and control than originally anticipated.

When compared to alternative (paid) third-party energy monitoring packages such as Solar Analytics, the Fronius Solar.web software could use some improvement on the user experience for the advanced analytical and beneficial data. A minor negative in a superior software package.


Fronius Symo Solar Inverter Logo - Solar Review

Very competitively priced against even the cheapest 3-phase inverters available. The level of quality and versatility ensures superior value for only a fraction more than the cheapest, uninspiring 3-phase solar inverters in the same category. It could be a big mistake to select anything less if price is the defining factor.

As a gauge, Fronius Symo 5.0-3 solar inverters are available online from USD 1700, AUD 2300, EURO 1450 excluding taxes, shipping and installation.

Source – Google.


Arguably one of the best 3-phase solar inverter options available. There is alot to like about the Fronius Symo. It will be interesting to see where to next for an excellent range, however with such refinement Fronius can enjoy the spoils a little longer until similar competing technologies reach the same heights in the small scale 3-phase division.


View the Fronius Symo score below. Got questions? Or have an alternative perspective? Have your say in the comments.


  1. I am using the Fronius Symo inverter for my 10 kw solar on grid system. I am getting only 80% efficiency. Can you please send someone to inspect the installation? Pradeep Vishnupriya.

    • Hey Pradeep, thanks for reaching out! Great to hear from friends all over this sunny planet. Getting to India is a bit of a stretch for our techies but let’s see if we can support you remotely as we are well versed with the Fronius Symo. Plus it costs nothing to ask! Let’s establish first what exactly you have. When you say running at 80% efficiency do you mean you have 10kW of solar panels on a 10kW Fronius Symo inverter only producing a total of 8kW on average?


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