Advanced 12/24V 230A Lithium Battery Combiner

Intelligent Dual Battery Management for LiFePO4 Systems

The Victron Cyrix-Li-ct is a highly sophisticated, microprocessor-controlled heavy-duty relay designed explicitly for dual battery setups that combine a traditional lead-acid starter battery with a LiFePO4 (Lithium Iron Phosphate) auxiliary battery. Managing the connection between two fundamentally different battery chemistries requires precision. This intelligent relay ensures your batteries are safely paralleled for charging while protecting your sensitive lithium cells from improper voltage levels and extreme temperature conditions. Operating seamlessly at both 12V and 24V with a robust 230A continuous current rating, it is engineered for demanding marine, RV, and off-grid automotive applications.

Seamless VE.Bus BMS Integration

Lithium batteries require strict operational parameters to prevent permanent cell damage. The Cyrix-Li-ct is designed to work in perfect harmony with the Victron VE.Bus BMS (Battery Management System). It actively monitors the Charge Disconnect output of the BMS. If the BMS detects an imminent cell overvoltage or high internal temperature, the control output becomes free-floating, and the relay immediately disengages to protect the battery bank. It will parallel connect your lead-acid and lithium batteries only when the BMS authorises charging and the relay senses at least 13.4V (or 26.8V for 24V systems) on one of its power terminals.

Built-In Transient Voltage Suppression

Sudden disconnections under heavy charge loads can create dangerous voltage spikes, which pose a significant risk to connected sensitive electronics. To mitigate this, the Cyrix-Li-ct features a built-in transient voltage suppressor. This critical safety component absorbs and limits any hazardous voltage spikes that may occur when the relay suddenly opens due to a BMS alarm, ensuring the continued safety of your vehicle or vessel's electrical network.

Start Assist Functionality

In emergency situations where your lead-acid starter battery is depleted, the Cyrix-Li-ct includes a highly practical start assist feature. By applying a short positive pulse to the dedicated control terminal, the relay forces the contacts closed for 30 seconds. This temporarily bridges the lithium house battery to the starter battery, providing the necessary cranking current to start your engine, ensuring you are never left stranded in remote locations.

Key Features

• Intelligent parallel connection of lead-acid starter and LiFePO4 house batteries
• Robust 230A continuous current rating for demanding high-draw systems
• Direct integration with Victron VE.Bus BMS for superior cell protection
• Integrated transient voltage suppressor to prevent damaging electrical spikes
• Emergency start assist function bridges batteries for 30 seconds
• Automatic 12V and 24V system voltage detection
• Disengages immediately upon BMS alarm or when battery voltage drops below 13.2V

Clear LED Status Indication

Monitoring the real-time operational status of your dual battery system is made straightforward via the integrated blue LED indicator on the top of the unit. The LED provides immediate visual feedback:

• Solid LED: Relay is engaged and batteries are paralleled
• 10-second flash: Relay is disengaged
• 2-second flash: Connection is pending
• 2-second blink: Disconnection is pending
• 0.25-second rapid blink: Alarm state (triggered by over-temperature, high voltage exceeding 16V, both batteries below 10V, or one battery below 2V)

Optimise Your Off-Grid Power Architecture

Relying on generic isolation switches for mixed-chemistry battery banks can lead to suboptimal charging and potential cell damage. Integrating this sophisticated relay into your electrical system ensures that your investment in premium lithium storage remains fully protected. Upgrade your mobile power system with the Victron Cyrix-Li-ct 12/24V 230A today and ensure safe, efficient, and intelligent battery management for your next journey.