Victron Redflow ZBM2 ZCell Flow Battery Compatibility Guide

Key Takeaways

• Redflow ZBM2 and ZCell are 48V 10kWh DC Zinc-Bromide flow batteries.
• Victron GX devices are strongly recommended for optimal integration and control.
• Connection methods vary: Modbus-RS485 for direct ZBM2, or CANBus for ZCell's integrated BMS.
• DVCC mode on the GX device is crucial for the Redflow BMS to manage Victron charge and discharge settings.

How do Redflow ZBM2 and ZCell flow batteries integrate with Victron Energy systems?

Redflow ZBM2 and ZCell flow batteries integrate with Victron Energy systems primarily through a Victron GX device, which manages communication and control. This setup allows the Redflow battery's BMS to dictate charge and discharge parameters to compatible Victron inverters and solar chargers.

Integrating Redflow ZBM2 and ZCell with Victron Systems

Integrating Redflow ZBM2 and ZCell flow batteries with Victron Energy systems involves specific connection methods and configuration steps to ensure proper communication and operation. The primary goal is to allow the Redflow battery's Battery Management System (BMS) to control the Victron charging and discharging processes.

1. Identify Your Redflow Battery Model:

• • Redflow ZBM2: This is the core 48V 10kWh DC Zinc-Bromide hybrid flow battery. For direct integration without the ZCell enclosure, it typically connects via Modbus-RS485.
  • Redflow ZCell: This is a packaged version of the ZBM2, including an external-rated enclosure and the Redflow CANbus BMS. It integrates via CANBus.

2. Select Compatible Victron Products:

• • Inverter/Chargers: All 48V Victron MultiPlus and Quattro models are compatible.
  • Solar Chargers: All 48V Victron solar chargers that support DVCC (Distributed Voltage and Current Control) are compatible. Older 'vertical' shaped CANBus units are not compatible with DVCC.
  • GX Device: A Victron GX unit (e.g., Cerbo GX, Color Control GX) running current firmware is strongly recommended for any Redflow integration. It is essential for enabling DVCC and facilitating communication.

3. Connect the Redflow Battery to the Victron GX Device:

• • For Redflow ZBM2 (direct connection): Connect the GX device to each ZBM2 battery in your system using Modbus-RS485. This requires a Victron RS485 to USB interface (part number ASS0305700xx) for each battery.
  • • Configuration: The GX device will automatically assign a unique Modbus address to each battery. Connect them slowly, one by one. Wait for each battery to appear on the GX device before connecting the next. Manual adjustment of the Modbus address is also possible.
    • Functionality: This connection allows the GX device to monitor battery voltage, current, state of charge, temperature, and various ZBM-specific alarms and flags. It also enables control functions like setting the battery to run mode, initiating maintenance cycles, and clearing alarms.
  • For Redflow ZCell (via BMS): The Redflow BMS, included with the ZCell package, interfaces with the GX device using CANBus. This is similar to how other modern 'smart' batteries communicate with Victron systems.

4. Enable DVCC Mode on the GX Device:

• • Regardless of the connection method (Modbus-RS485 or CANBus), always enable DVCC mode in the Victron GX device settings.
  • Purpose: DVCC allows the Redflow BMS to control the voltage and current settings of connected Victron inverter/chargers and solar chargers via the communication bus. This means you do not need to manually set battery voltage or current limits in VE.Configure, as the BMS will manage these dynamically.

5. Configure ESS (Energy Storage System) for On-Grid Sites (if applicable):

• • If using the system in an on-grid ESS configuration, select the "Redflow ZCell" battery type in the ESS Assistant during setup. This option has been available in ESS Assistant versions since April 2020.
  • Operating Mode: Use the ESS mode "Optimised (without BatteryLife)" to allow for full-depth discharge of the battery regularly, which is suitable for flow battery characteristics.
  • MinSoC Setting: For single battery setups, the ESS 'MinSoC' (Minimum State of Charge) must be set to 0% to prevent stalling the ZCell's maintenance cycle.

Compatibility and Connection Overview

Safety: Zinc-Bromide Flow Battery Characteristics

Redflow ZBM2 and ZCell batteries utilize zinc-bromide flow battery technology, which offers specific safety characteristics. These batteries are noted for their low fire risk. They do not exhibit an exothermic reaction if exposed to fire, and their water-based fluid electrolyte is intrinsically fire-retardant. This chemistry contributes to a safer operating environment compared to some other battery types.

When to call a technician instead

While this guide covers compatibility and basic setup, complex installations or persistent communication issues may require professional assistance. If you encounter problems that cannot be resolved by following these steps, or if you are unsure about any wiring or configuration, contact a qualified solar or battery technician. Opening the battery unit or attempting repairs beyond documented procedures may void warranties.