Victron Cyrix-Li-load 12/24V-230A: Intelligent Load Disconnect for LiFePO4 Battery Systems

Precision Protection for Your Lithium Battery Investment

The Victron Cyrix-Li-load 12/24V-230A is a specialised intelligent load relay engineered to safeguard LiFePO4 (lithium iron phosphate) batteries from damaging under-voltage conditions. Designed to integrate seamlessly with a VE.Bus BMS, this relay acts as a critical second line of defence, automatically disconnecting loads when cell voltages approach unsafe levels. By preventing deep discharge, it helps extend battery cycle life and maintain system reliability in mobile, marine, and off-grid applications.

Unlike generic voltage-sensitive relays, the Cyrix-Li-load responds directly to the BMS control signal, ensuring precise, cell-level protection rather than relying solely on overall battery voltage. This targeted approach reduces the risk of premature cell failure and the associated downtime or replacement costs.

How It Works: BMS-Driven Load Management

The Cyrix-Li-load engages when its control input receives a high signal (approximately battery voltage) from the VE.Bus BMS, allowing normal load operation. If the BMS detects an imminent cell under-voltage, it releases the control input, causing the relay to disengage and isolate the loads. This immediate response prevents further discharge and protects the cells.

After disconnection, battery voltage often recovers slightly. The Cyrix-Li-load will attempt to re-engage after a 30-second delay. If the under-voltage condition persists, it will try up to three times before locking out. To reset, the battery voltage must rise above 13 V (26 V for 24 V systems) for at least 30 seconds, indicating that charging has resumed. This intelligent logic avoids nuisance cycling while ensuring loads are only reconnected when safe.

Key Features at a Glance

• 230 A continuous rating at 12 V or 24 V, suitable for high-demand DC loads
• Direct BMS integration via included 1-metre control cable for precise cell-level protection
• Low power consumption (<4 mA when open) to minimise drain on the battery
• IP54 protection against dust and water spray, ideal for engine rooms and exposed installations
• LED status indicator for at-a-glance monitoring of relay state and alarm conditions
• Compact, lightweight design (65 x 100 x 50 mm, 0.27 kg) for flexible mounting
• M8 stud terminals (approx. 5/16") accept heavy-duty lugs for secure, low-resistance connections

Built for Demanding Environments

With an IP54-rated enclosure, the Cyrix-Li-load resists dust ingress and splashing water, making it suitable for use in marine engine compartments, vehicle under-bonnet installations, and other harsh settings. The robust M8 stud terminals ensure reliable high-current connections, while the integrated transient voltage suppressor protects against spikes that can occur during sudden disconnection.

Applications: Where Precision Load Control Matters

This relay is essential in any LiFePO4 system where loads cannot be directly controlled by the VE.Bus BMS. Typical use cases include:

• Marine and RV electrical systems – Protect house batteries from being drained by DC distribution panels, inverters, or other loads
• Off-grid solar installations – Prevent over-discharge of lithium battery banks in remote power systems
• Industrial and mobile equipment – Safeguard batteries in electric vehicles, forklifts, or portable power packs

For systems requiring ultra-low standby consumption, a Victron BatteryProtect may be considered as an alternative. However, the Cyrix-Li-load offers the advantage of bidirectional current flow and higher continuous current handling.

Installation and Compatibility

The Cyrix-Li-load is designed for straightforward integration with Victron VE.Bus BMS units. The included control cable connects directly to the BMS load disconnect output. Always ensure the relay is installed in a well-ventilated area and that cable sizing is appropriate for the 230 A continuous rating. Note that typical de-rating factors apply for sustained high-current operation; refer to installation guidelines for optimal performance.

Protect Your Lithium System Today

Add the Victron Cyrix-Li-load 12/24V-230A to your energy system and gain peace of mind knowing your LiFePO4 batteries are shielded from damaging under-voltage events. Order now to ensure reliable, automated load disconnection for your next project.