Victron VE.Bus BMS V2: Setup & Battery Guide

Key Takeaways

• The Victron VE.Bus BMS V2 provides complete battery management for Victron Lithium Battery Smart cells across an Input voltage range 9 – 70Vdc.
• Engineered for minimal standby power consumption: Current draw - regular operation 10mA (excluding Load disconnect current), Current draw - low cell voltage 2mA, and Current draw - switched off via remote on/off terminal 1.50mA.
• Features a dedicated GX-pow output 1A Aux-in input 1A port that powers the system GX device during normal operation and disconnects it during low-voltage events.
• Includes a Pre-alarm output current rating 1A, not short circuit protected for early warning before load disconnect occurs.
• Controls external DC loads with Load disconnect output Normally high (output voltage ≈ supply voltage – 1V) Floating when the load needs to be disconnected Source current limit: 1A.
• Controls solar chargers and DC charging sources with Charge disconnect output Normally high, (output voltage ≈ supply voltage – 1V) Floating when charger should be disconnected Source current limit: 10mA.
• Supports versatile remote logic: ON when the L and H terminal are interconnected (switch or relay contact), ON when the L terminal is pulled to battery minus (V<3.5V), or ON when the H terminal is high (2.9V < VH < Vbat).
• Seamlessly interfaces with inverters via VE.Bus communications ports 2 x RJ45 sockets to connect to all VE.Bus products.

System Architecture & GX-Pow Isolation

The VE.Bus BMS V2 manages cell balancing, over-voltage, under-voltage, and temperature monitoring across Victron Lithium Smart LiFePO4 battery banks. It communicates directly with MultiPlus and Quattro inverters over standard RJ45 VE.Bus patch cables.

The Victron VE.Bus BMS V2 is a battery management system operating across a 9 to 70V DC range (Quiescent Draw: 10mA Regular | 2mA Low-Cell | 1.50mA Switched Off) with dedicated system gating and communication ports:

• System Power Gating: GX-pow Output (1A), Aux-in Input (1A), Pre-Alarm Out (1A), Deep Drain Cutout.
• Control Terminals: Load Disconnect (1A Source Limit), Charge Disconnect (10mA Limit).
• Inverter Bus: 2x RJ45 Port, VE.Bus Direct, MultiPlus II, Quattro Sync.

Eliminating Parasitic GX Controller Drain

1. GX-Pow Operation: In older installations, a connected GX device (such as a Cerbo GX) drew power directly from the battery bank even after low-voltage load disconnection, eventually causing catastrophic deep discharge of lithium cells.
2. Automated Power Cutout: The VE.Bus BMS V2 includes a dedicated GX-pow output 1A Aux-in input 1A port. When cell voltage falls into critical territory, the BMS shuts down power to the GX-pow port, safeguarding the battery bank against parasitic drain.

Control Outputs & Remote Logic Wiring

The VE.Bus BMS V2 integrates multi-channel load and charge management:

• Load Disconnect Output: Operates as Load disconnect output Normally high (output voltage ≈ supply voltage – 1V) Floating when the load needs to be disconnected Source current limit: 1A. Connect to the remote on/off terminal of a BatteryProtect or DC relay.
• Charge Disconnect Output: Operates as Charge disconnect output Normally high, (output voltage ≈ supply voltage – 1V) Floating when charger should be disconnected Source current limit: 10mA. Connect to the remote on/off pins of SmartSolar MPPT controllers or Orion-Tr chargers.
• Pre-Alarm Output: Provides a Pre-alarm output current rating 1A, not short circuit protected signal to sound a buzzer or illuminate an indicator prior to actual load disconnection.
• Remote Switching: The unit enables flexible system switching: ON when the L and H terminal are interconnected (switch or relay contact), ON when the L terminal is pulled to battery minus (V<3.5V), and ON when the H terminal is high (2.9V < VH < Vbat).

Technical Specifications & Integration