Fronius Primo GEN24 4.0 Plus4kW single-phase hybrid inverter with battery input and Full Backup

Overview

The Primo GEN24 4.0 Plus is the 4kW single-phase hybrid version of Fronius' GEN24 range, with a high-voltage battery input (150–455V, 22A), PV Point and Full Backup. Its two MPP trackers take 22A and 12A and up to 6kWp of PV in total (5kWp on MPPT1, 4.14kWp on MPPT2), while 4,140W of DC power is available for AC output or battery charging. Full Backup supplies 4,000VA once external switchover components are installed. Fronius recommends a 40A AC circuit breaker.

• 3.0–6.0kW single-phase, two MPP trackers, 65–600V DC input
• Plus versions: battery input 150–455V, 22A
• PV Point: 3kVA single-phase backup circuit on every model
• Full Backup at rated power on Plus versions
• Approved for Fronius Reserva, Reserva Pro, BYD and LG FLEX
• IP66, -40…+60°C, active cooling, integrated datalogger

How it works

Primo GEN24 is a transformerless single-phase inverter for 220/230V grids in six power classes: 3.0, 3.6, 4.0, 4.6, 5.0 and 6.0kW. Two MPP trackers work from 65V to 600V, with 22A on the first and 12A on the second, so a main roof face and a smaller second string can be optimised separately. PV power covers the building's loads first; on a Plus model the surplus charges a DC-coupled high-voltage battery.

Every model includes PV Point, a single-phase circuit of up to 3kVA that the inverter supplies from PV or battery after a grid failure, with a switching time under 15s. It is not an uninterruptible supply. The Plus versions add Full Backup, which supplies the backed-up circuits at the inverter's rated power in under 10s once the electrician installs external switchover components such as the Fronius Backup Controller or Backup Switch.

Key features

Usable DC power runs from 3,110W on the 3.0 to 6,200W on the 6.0, with a maximum PV array of 4.5 to 9kWp depending on the model. Maximum efficiency is 97.6% and European efficiency 96.8–97.2%. Active cooling, an IP66 housing and an ambient range of -40 to +60°C allow outdoor installation up to 4,000m. Where Fronius UP is offered, the standard versions can be given battery support and Full Backup later by software upgrade.

Installation and compatibility

Fronius approves the Primo GEN24 Plus with Reserva 6.3–9.5kWh, Reserva Pro with 3–5 modules, BYD Battery-Box HVS/HVS+ 5.1–7.7kWh, HVM/HVM+ 11.0–19.3kWh and LG FLEX 8.6 or 12.9kWh, subject to national certification. An open-circuit PV voltage of no more than 520V is recommended, because the battery can neither charge nor discharge while any tracker is above 520V.

The AC side needs a circuit breaker of at most 63A; Fronius recommends 32A for the 3.0 and 3.6 and 40A for the 4.0 to 6.0. Where a residual current device is required, type A is generally sufficient, and a frequency-inverter-type device of at least 100mA is recommended. Mount on a solid, non-flammable surface away from direct sunlight and outside living areas, as the fan can be audible.

Monitoring and settings

An integrated datalogger and web server connect over WLAN or two Ethernet ports to Fronius Solar.web. Commissioning runs through the Fronius Solar.start app or the browser setup wizard. Modbus TCP SunSpec and the Fronius Solar API (JSON) are open, two RS485 ports serve the Fronius Smart Meter, battery, Ohmpilot or third-party Modbus RTU devices, and 6 digital inputs plus 6 inputs/outputs handle ripple control and energy management.

Questions and answers