Cyrix-Li-ct 12/24V-230A Intelligent Li-ion Battery Combiner

The Victron Cyrix-Li-ct is a microprocessor-controlled battery combiner designed specifically for lithium-ion battery systems operating at 12V or 24V. It replaces a conventional VSR (voltage-sensitive relay) in dual-battery installations where a Li-ion service bank is paired with a starter battery, allowing charge sharing without risking damage to either battery. It is suited to marine, vehicle and off-grid applications where lithium batteries are in use.

Key Features

• Rated at 230A continuous current, suitable for high-demand dual-battery installations.
• Compatible with 12V and 24V systems, covering the most common Li-ion battery configurations.
• Microprocessor-controlled logic replaces a standard VSR, with behaviour specifically tailored to lithium battery charge and discharge profiles.
• Designed to receive a control signal from a Li-ion BMS, allowing the BMS to open the combiner in the event of a fault condition such as over-voltage or over-temperature.
• Compact and lightweight at 0.3 kg, making it straightforward to install in confined spaces such as engine bays or battery compartments.
• Prevents the starter battery from being discharged by the lithium service bank, protecting engine start capability.

Product Overview

The Cyrix-Li-ct operates differently from a standard voltage-sensitive relay. Rather than simply connecting batteries when a threshold voltage is detected, it is designed to work in conjunction with the charge/discharge control outputs of a compatible Li-ion BMS. When the BMS signals that the lithium battery is approaching an unsafe state, the Cyrix-Li-ct opens the connection between the two banks, isolating the lithium battery from the rest of the system. This is a critical safety function that a conventional VSR cannot provide.

The "ct" designation refers to the charge/discharge control terminals on the unit. These terminals accept a signal from the BMS to either allow or interrupt the combining function. In practice, this means the combiner behaves intelligently based on battery state rather than voltage alone, which is essential when working with lithium chemistries that have a much flatter discharge curve than lead-acid batteries.

At 230A, the unit handles the current demands of typical alternator charging and high-load scenarios without derating. The 12/24V compatibility makes it a single stock item for installers working across different system voltages, reducing the need to carry multiple variants.

Specifications

• SKU: CYR010230412
• System voltage: 12V / 24V
• Continuous current rating: 230A
• Control interface: Charge/discharge control terminals (BMS signal input)
• Weight: 0.3 kg
• GTIN: 8719076034346

Applications

• Marine vessels with a lithium service bank and a separate lead-acid or AGM starter battery.
• Campervans, motorhomes and HGVs using lithium leisure batteries alongside a vehicle starter battery.
• Off-grid vehicles and mobile installations where alternator charging feeds a Li-ion battery bank.
• Any dual-battery system where BMS-controlled isolation of the lithium bank is required for safe operation.

What Is Included

• 1 x Victron Cyrix-Li-ct 12/24V-230A battery combiner

Installation Notes

Installation should be carried out by a qualified electrician or experienced marine/vehicle electrical engineer. The Cyrix-Li-ct must be wired to the charge/discharge control output of a compatible Li-ion BMS for the protection functions to operate correctly. Connecting this unit without a BMS control signal will prevent the safety isolation feature from functioning as intended. Ensure all cabling is rated for the 230A continuous load and that appropriate fusing is installed on both battery connections. For marine installations, follow the relevant wiring standards for your vessel class.