Fronius Reserva Pro battery module 3.98kWh3.98kWh 70.84V LFP module for the Fronius Reserva Pro high-voltage battery

Overview

The Reserva Pro module (item 4,240,390) stores 3.98kWh at 70.84V nominal and is the building block of the Fronius Reserva Pro battery. Three to eight modules stacked on a Reserva Pro base under a Reserva Pro BMS give 11.9 to 31.9kWh usable per tower at 212.5–566.7V, with up to 50A output current; BMS and base are ordered separately. Each module weighs 36kg and measures 160×570×440mm. Fronius states that the cells and modules are made in Europe.

• 3.98kWh, 70.84V LFP modules, 3–8 per tower
• 11.9–31.9kWh usable per tower, up to 4 towers
• Max. 50A output current per installation
• IP65, safety class II, -20…+50°C
• 10-year warranty to 80% state of health
• Cells and modules made in Europe

How it works

Reserva Pro is a DC-coupled, stackable high-voltage battery for Fronius hybrid inverters with higher energy and current demand than the standard Reserva. A tower combines a base, three to eight 3.98kWh modules and a BMS, giving 11.9 to 31.9kWh usable at 212.5–566.7V nominal. Up to four towers of equal capacity can be paralleled, which Fronius states as up to 128kWh in total.

The BMS monitors voltage, current, temperature and cell condition, calibrates the state of charge monthly and can balance modules automatically after a module is added or replaced. It communicates with the inverter over Modbus (RS485) and to the modules through an ISO-SPI bus. After a shutdown the battery supports a manual dark start of the backup system.

Key features

Maximum output current is 50A, limited by the inverter, which gives up to 11.8kW charge and discharge on a three-module tower according to the manual. The modules use lithium iron phosphate cells, and Fronius states that both cells and modules are made in Europe. The enclosure is IP65 with safety class II and convection cooling, and the module self-discharge is no more than 1% per month at 25°C.

Installation and compatibility

Fronius approves Reserva Pro with the Primo GEN24 Plus and Plus SC (3–5 modules), Symo GEN24 Plus and Plus SC and Verto Plus (3–8 modules). Install indoors or in protected outdoor areas, ventilated to the outside if needed, at -20 to +50°C and up to 2,000m, on a load-bearing, non-combustible surface with 300mm on each side. DC cables may run up to 40m to the inverter and 7m between towers.

Monitoring and settings

The state of charge and operating data are shown in Fronius Solar.web, and the battery is registered in the inverter's user interface during commissioning. Firmware updates for the BMS are installed through the inverter. To extend a tower, service mode sets the modules to a common state of charge before the new module is fitted, after which automatic balancing evens out small differences.

Questions and answers