Fronius makes Austrian solar inverters for residential, commercial and ground-mount use: the single-phase Primo and Primo GEN24, the three-phase Symo and Symo GEN24 Plus, and the Verto and Tauro families. The GEN24 units come with a built-in data logger and web server, Modbus TCP SunSpec communication and basic PV Point backup.
What it is and where it is used
Fronius is an Austrian manufacturer of solar inverters, battery chargers and welding equipment. In solar energy it produces single-phase (Primo) and three-phase (Symo) grid-tied inverters. It also produces the GEN24 generation (Primo GEN24 and Symo GEN24 Plus, with battery and backup) and the Verto and Tauro families. Fronius groups these two families with the GEN24 units in its firmware updates and on its manuals page.
They are used in homes, businesses and industrial rooftops. Fronius documents on its site a 193 kWp plant from 2019 with eight Symo inverters of 24, 20 and 15 kW, a Smart Meter and the Solar.web portal, installed by a Fronius Service Partner. It is a case from the manufacturer; current distributors are confirmed with Fronius.
For the inverter concept, see DC-DC converters and inverters.
Other string and hybrid inverter brands with their own guide: Solis inverters, Deye hybrid inverters, Growatt inverters and Chint Power CPS inverters.
Microinverter guides are also available for the Enphase IQ8 microinverters and Hoymiles microinverters.
Variants: Primo, Symo, GEN24, Verto and Tauro
| Model | Application | Main difference |
|---|---|---|
| Fronius Primo | Residential | Single-phase, pre-GEN24 line |
| Fronius Symo | Large home and commercial | Three-phase, pre-GEN24 line; in the case above, 15, 20 and 24 kW |
| Primo GEN24 (for example 7.7 and 3.8) | Residential | Single-phase, 2 MPPTs, built-in data logger, PV Point and battery option |
| Symo GEN24 Plus (3.0 to 12.0, and SC versions) | Residential and small commercial | Three-phase with battery and built-in backup; the 12.0 Plus SC accepts up to 18 kWp of array with 12 kVA output |
| Verto (15.0 to 33.3) | Commercial | Three-phase, 15 to 33.3 kW with 3 or 4 MPPTs; data in the next section |
| Tauro (50 and 100 kW) | Commercial and ground-mount | Three-phase, 50 to 100 kW class, with the single-MPPT Tauro Eco; data in the next section |
| Datamanager 2.0 | Monitoring | Communication card for the earlier-line inverters |
The power ratings and the 2 MPPTs come from Fronius USA’s page for the Primo GEN24 7.7 208-240; versions for other countries change in voltage and designation.
Main features
- Backup. PV Point provides basic backup without a battery, with a transfer time of up to 22 s. Full Backup, for the whole home, requires a battery and a disconnection device and takes up to 17 s, according to Fronius.
- Maximum power point tracking. Two independent MPPTs, wide input voltage windows and oversizing of up to 150%. The criterion for the ratio between array and inverter is in inverter DC/AC ratio and clipping. Fronius states that its Dynamic Peak Manager finds the global maximum power point under partial shading.
- Environment. The Symo GEN24 Plus units are installed indoors or outdoors, from −25 to 60 °C, according to the Fronius datasheets.
- Inputs and outputs. Six digital inputs/outputs and six digital inputs for ripple control and energy management, and an emergency stop input (WSD), related to the rapid shutdown of PV systems.
Verto and Tauro: data from the Fronius datasheets
Verto. The Fronius datasheet groups two blocks. All are three-phase and transformerless. Their input voltage range is 150 to 1000 V, with a start-up voltage of 150 V, a rated input voltage of 600 V and an MPP range of 150 to 870 V. They offer 28 A usable per MPPT (50 A short-circuit per MPPT):
| Model | Rated AC power | MPPTs | Maximum PV array power |
|---|---|---|---|
| Verto 15.0 | 15,000 W | 3 | 22.5 kWp |
| Verto 17.5 | 17,500 W | 3 | 26.25 kWp |
| Verto 20.0 | 20,000 W | 3 | 30 kWp |
| Verto 25.0 | 25,000 W | 3 (400 version) or 4 | 37.5 kWp |
| Verto 27.0 | 27,000 W | 4 | 40.5 kWp |
| Verto 30.0 | 29,990 W | 4 | 45 kWp |
| Verto 33.3 | 33,300 W | 4 | 50 kWp |
The datasheet lists these built-in items: DC disconnect, insulation measurement, residual current monitoring unit (RCMU), DC arc protection (Fronius Arc Guard) and reverse polarity protection. Surge arresters on DC and AC, the stop input (WSD) and the data logger with web server follow. Communications are WLAN, two 10/100 Mbit RJ45 Ethernet ports (up to 100 m), two RS485 ports for Modbus RTU SunSpec or the Smart Meter, and six digital inputs and six digital inputs/outputs. Protection rating IP66, indoor or outdoor installation, from −40 to +60 °C, and altitude of 3000 m without voltage restriction (4000 m with a restricted voltage range). The 25 to 33.3 kW models weigh 41.75 kg according to the sheet; the 15 to 25 kW (400 version) ones, 35.2 kg.
Tauro. The technical data page for the Tauro Eco 100-3-D describes a three-phase transformerless inverter of the 50 to 100 kW class, with active cooling and a double wall, installable indoors or outdoors, even in full sun. Its data: 1 MPPT, 175 A maximum input current, an input range of 580 to 1000 V, start-up at 650 V and an MPP range of 580 to 930 V. It accepts up to 150 kWp of array and delivers 100 kW at 380/220 V or 400/230 V. Its maximum efficiency is 98.5%, with IP65, 103 kg and operation from −40 to +65 °C. Each PV input (PV1, PV2 and PV3) accepts 75 A and 125 A short-circuit, with a 20 A string fuse as standard and a 30 A option. Arc protection is optional and only available with the 20 A option. The same pages list certifications such as IEC 62109-1/-2, IEC 62116, IEC 61727, VDE-AR-N 4105 and 4110; the grid profiles for each country are confirmed with Fronius.
Two design points follow from those sheets. First, the number of MPPTs (1 on the Tauro Eco, 3 or 4 on the Verto) determines how many orientations or string groups can have independent tracking. Second, the minimum MPP ranges at rated power determine how many modules per string are needed to deliver full power; for example, 335 V to 870 V on the Verto 25.0 400 version, against 275 V on the Verto 20.0. For the calculation see PV string sizing.
Communications and integration
The GEN24 units come with Wi-Fi, two Ethernet ports, a web server and a built-in data logger, and are integrated through Fronius Solar.web, Modbus TCP SunSpec and the Fronius Solar API (JSON); two RS485 ports connect the Fronius Smart Meter or Modbus RTU SunSpec devices. On the earlier-line inverters the Datamanager performs that function, and Fronius warns in its change logs that inverters on a connected Datamanager only accept addresses 1 to 5.
To integrate inverters into a plant controller or SCADA, see solar plant controller (PPC). The connection of small installations that export surplus energy follows the utility’s interconnection rules.
Frequently asked technical questions
- Manual for a Fronius Symo GEN24 Plus: Fronius publishes operating instructions per model at manuals.fronius.com and datasheets in its technical section. Use those for your model and country.
- Firmware update: each GEN24 firmware version has a public change log; updating changes functions, so reading it first is recommended.
- The inverter does not communicate with Solar.web: check the local network, the device name and the communication settings.
- It disconnects from the grid: it may be the inverter’s own protection or that of the point of connection.
What to check before connecting it to the grid
- Designation by country. Fronius separates its models by region (208-240 V in the US, 230 V in Europe). Choose the version that matches the voltage at the site and its grid code.
- Backup and battery. PV Point does not require a battery but only works with sun; Full Backup requires a battery and the grid disconnection device. Define backup at the service-entrance design stage, not at the end. The architecture of a system with batteries is in hybrid solar system with batteries.
- Meter. The Fronius Smart Meter connects through RS485 and feeds the export control and consumption monitoring; verify that the installation point is where the utility allows it.
- Firmware. Fronius publishes change logs per version; read it before updating.
- Cybersecurity and remote access. If the inverter is connected to the internet, restrict access and use your own passwords.
How we help
Our work on an installation with Fronius inverters is the grid connection: connection studies, point-of-connection protection and its commissioning. For commercial or ground-mount plants, solar plant commissioning covers transformer stations, substation and protection. To define your project’s connection, see grid connection studies. Field work is in Colombia, or elsewhere on request; remote services are available worldwide. Write to us through contact.
Related guides
- DC-DC converters and inverters
- The inverter disconnects from the grid
- Inverter DC/AC ratio and clipping
- Rapid shutdown in PV systems
- Hybrid solar system with batteries: AC or DC coupling
References
- Fronius, technical data pages for the Primo GEN24 and Symo GEN24 Plus, operating manuals and firmware change logs for GEN24 / Verto / Tauro.
- IEC 62109-1 and 62109-2; IEC 62116.
Frequently asked questions
What is the difference between a Fronius Primo and a Fronius Symo?
The Primo is single-phase and the Symo is three-phase, as Fronius's own families indicate. Both exist in the earlier line and in the GEN24 (Primo GEN24 and Symo GEN24 Plus), which adds a built-in data logger and backup and battery functions.
What is PV Point on a Fronius GEN24?
It is basic backup without a battery: an outlet on the inverter keeps essential loads powered when the grid fails and the sun is shining. According to Fronius, the transfer takes up to 22 s. Full Backup requires a battery and a grid disconnection device.
Where can I get Fronius inverters and support in my country?
Availability and support depend on the country and are confirmed with Fronius or its local distributor. Fronius separates its models by region, so the version has to match the grid voltage and the local grid code.