FoxESS Mira-HV25 2.45kWh battery module2.45kWh 51.2V module for Mira high-voltage systems

Overview

The Mira-HV25 is the 2.45kWh building block of FoxESS's Mira system: a 51.2V, 48Ah lithium iron phosphate module of 440×420×122mm and 30.2kg. Two to eight modules are wired in series under one Mira-BMS controller, for 4.9–19.6kWh at 102.4–409.6V nominal and 48A continuous. With IP21 protection, it is meant for indoor installation inside an approved Fox enclosure, with at most four modules per stack.

• 2.45kWh, 51.2V, 48Ah modules
• 2 to 8 modules per Mira-BMS, 102.4–409.6V
• 48A continuous, 60A peak current
• Up to 4 modules per stack
• IP21: indoor installation in a FoxESS enclosure
• More than 4000 cycles to 80% SOH

How it works

Mira is a modular system made of Mira-HV25 battery modules and one Mira-BMS controller. Each module contains 2.45kWh of lithium iron phosphate cells; modules are wired in series with plug-in power leads and daisy-chained CAN cables, and the Mira-BMS sits between the module string and the inverter. A system needs at least two and at most eight modules, giving 102.4V to 409.6V nominal at 48Ah.

Key features

The string supplies 48A continuously, 24A recommended for charging, and 60A peak. FoxESS specifies more than 95% charge and discharge efficiency and over 4000 cycles at 25°C to 80% state of health, with a usable SOC window of 3–100%. The Mira-BMS has a black-start switch, SOC LEDs, a buzzer and both CAN and RS485 lines on its PCS port, and assigns module addresses automatically at first start-up.

Installation and compatibility

The modules are rated IP21 and are not water-resistant. FoxESS's manual states they may only be installed inside an approved Fox enclosure, kept away from water, with 300mm of free space around the pack for natural convection. Brackets are supplied separately. Each stack holds at most four modules with one BMS; larger systems are split into several stacks. After series wiring, the measured voltage should be about 52V per module.

Only batteries with the same colour of SN label may be combined in one system, and other battery types must not be mixed in. The Mira-BMS package contains 1.2m DC output cables of 8AWG, a 1m grounding cable of 10AWG and the BMS-to-inverter communication cable. When starting a grid-connected system, the inverter is switched on before the battery to avoid current pulses into the pack.

Monitoring and settings

Each module has a green power LED and a red alarm LED; the Mira-BMS displays state of charge on four LEDs and signals faults with combined LED codes listed in the manual. Charging and discharging are controlled by the hybrid inverter over CAN, and the battery appears in the inverter's monitoring.

Questions and answers