Fronius Primo 12.5-1 TL 1-Phase 208/240VAC Grid-Tie Inverter

  • Arc Fault Circuit Interruption Integrated
  • Flexible Design
  • Free Integrated Wi-Fi
  • SnapINverter Hinge Mounting System
  • Field Serviceable for Lowest Cost of Ownership
SKU 12.5-1 208-240 Categories ,


Recommended PV power (kWp) 10.0 kW – 15.0 kW
Max. usable input current (MPPT 1/MPPT 2) 49.5A/27A
Max. array short circuit current (1.25 Imax) (MPPT 1/MPPT 2) 41.3A/22.5A
Operating voltage range 80 V – 600 V
Max. input voltage 600 V
Nominal input voltage 425 V
Admissable conductor size DC AWG 14 – AWG 6 copper direct, AWG 6 aluminum direct, AWG 4 – AWG 2 copper or aluminum with input combiner
MPP Voltage Range 260 – 480 V
Integrated DC string fuse holders 4- and 4+ for MPPT 1 / no fusing requried on MPPT 2
Number of MPPT 2
Max. output power 208 / 240 V 12500 W
Max. continuous output current 208 / 240 V 60.1 A / 52.1 A
Max. efficiency 96.7%
Admissable conductor size AC (AWG 10 copper or AWG 8 aluminum for overcurrent protective devices up to 60A, from 61 to 100A minimum AWG 8 for copper or AWG 6 aluminum has to be used)
Grid connection 208 / 240 V
Frequency 60 Hz
Total harmonic distortion -< 2.5%
Power factor (cos φac,r) 0 – 1 ind./cap.
General Data
Dimensions (width x height x depth) 20.1 x 28.5 x 8.9 in.
Weight 82.5lbs
Degree of protection NEMA 4X
Night time consumption < 1 W
Inverter topology Transformerless
Cooling Variable speed fan
Installation Indoor and outdoor installation
Ambient operating temperature range -40 – 140°F (-40 – 60°C)
Permitted humidity 0 – 100 %
DC connection terminals 4x DC+1, 2x DC+2 and 6x DC- screw terminals for copper (solid / stranded / fine stranded) or aluminum (solid / stranded)
AC connection terminals Screw terminals 12-6AWG
Certificates and compliance with standards UL 1741-2015, UL1998 (for functions: AFCI, RCMU and isolation monitoring), IEEE 1547-2003, IEEE 1547.1-2003, ANSI/IEEE
C62.41, FCC Part 15 A & B, NEC Article 690-2014, C22. 2 No. 107.1-01 (September 2001) , UL1699B Issue 2 -2013, CSA TIL M-07
Issue 1 -2013
AFCI & 2014 NEC Ready Yes
Ground Fault Protection with Isolation Monitor
DC disconnect Yes
DC reverse polarity protection Yes
Wi-Fi/Ethernet/Serial Wireless standard 802.11 b/g/n / Fronius Solar.web, SunSpec Modbus TCP, JSON / SunSpec Modbus RTU
6 inputs or 4 digital inputs/outputs External relay controls
USB (A socket) Datalogging and/or updating via USB
2x RS422 (RJ45 socket) Fronius Solar Net, interface protocol
Datalogger and Webserver Included



Fronius is a global technology leader in the field of solar energy generation and storage solutions, as well as welding technology and battery charging technology. With a strong focus on quality, reliability, and sustainability, Fronius offers a range of innovative photovoltaic inverters, energy storage systems, and monitoring tools designed to optimize solar energy production and consumption. As a committed advocate for reducing the world's carbon footprint and promoting the use of renewable energy sources, Fronius continues to develop cutting-edge solar technology that helps customers worldwide meet their energy needs in an environmentally responsible way. With a reputation for exceptional quality, efficiency, and durability, Fronius' solar products are trusted by customers worldwide.


Arc Fault Circuit Interruption Integrated

The Fronius Arc Fault Circuit Interruption (AFCI) is the best of its kind in the industry. The technology makes each inverter NEC 2011 compliant and maintains some of the most civilized, integrated technology available today. Ensuring the utmost safety, AFCI shuts down the inverter in the event of an arc fault.


Flexible Design

Two MPP trackers combined with a high system voltage and wide input voltage range guarantee maximum flexibility. Every DC input, and therefore every MPP tracker, is able to accommodate the entire nominal output of the inverter. The result: an inverter for every application. Thanks to a new MPP tracking algorithm, a single inverter can cope with any challenge – including different roof orientations, shading of one or two strings, or the use of residual modules.


Free Integrated Wi-Fi

Simple, user-friendly system monitoring is very important to Fronius. With the Fronius Datamanager 2.0, we are the first inverter manufacturer to offer a Wi-Fi interface in the inverter itself. The inverter is connected to the internet without additional cabling and grants you the perfect overview of how the PV system is operating.


SnapINverter Hinge Mounting System

The special feature in the design of our devices is that the connection compartment is separate from the power stage set compartment. They are installed separately. The connection area and all its cabling is fitted to the wall first. The power stage set compartment is fitted afterwards. The innovative SnapINverter mounting system makes installation and servicing extremely user-friendly. The inverter is simply placed in the wall bracket and then secured. It is not necessary to remove the entire inverter for servicing, just the power stage set compartment. All the cabling, settings and configurations remain in place.


Field Serviceable for Lowest Cost of Ownership

The foundation of the unique PC board replacement process is laid as we develop our inverters, as PC boards can only be replaced if the device has been designed accordingly. This enables our Fronius Service Providers to provide the fastest inverter servicing on the market.