Victron Energy - 12/24V - Cyrix-ct Intelligent Battery Combiner 12/24V-230A VSR

Victron Cyrix-ct 12/24V-230A: Intelligent Battery Combiner for Dual-Battery Systems

Advanced Voltage Sensing Relay for Reliable Parallel Charging

The Victron Cyrix-ct 12/24V-230A is a microprocessor-controlled voltage sensitive relay (VSR) designed to intelligently manage dual-battery systems in vehicles, boats, and off-grid installations. Unlike conventional split charge relays that rely on simple voltage thresholds and fixed time delays, the Cyrix-ct uses intelligent trend detection to prevent unwanted switching caused by momentary voltage dips or spikes. This ensures your auxiliary battery bank charges reliably without premature disconnection, even when powering high-demand loads.

Engineered for 12V and 24V auto-ranging systems, this 230A continuous battery combiner is an ideal solution for caravan battery charging, marine dual-battery setups, 4x4 auxiliary power, and commercial vehicle electrical systems. Its bidirectional voltage sensing and dual power supply allow it to engage from either battery side, making it a versatile component in any DC charging architecture.

Intelligent Trend Detection: Smarter Than a Standard VSR

Traditional battery combiners often disconnect under short, high-amperage loads or fail to connect a deeply discharged battery bank because the voltage immediately drops below the disengage threshold. The Cyrix-ct overcomes these limitations by analysing the voltage trend over time. It only reverses a connection decision if the trend has genuinely reversed, with a time delay proportional to the voltage deviation. This prevents nuisance switching and ensures stable, continuous charging.

Key Features

• 230A continuous current rating with 500A cranking capacity for 5 seconds, supporting large battery banks and high inrush loads
• 12/24V auto-ranging automatically detects system voltage, simplifying installation across mixed fleets
• Bidirectional voltage sensing and dual power supply allow engagement from either battery, ideal for alternator or shore charger input
• Start Assist function enables manual parallel connection for 30 seconds via push button or switch, providing emergency cranking power from the auxiliary battery
• Over-temperature protection disengages the relay if contact temperature exceeds safe limits, automatically reconnecting after cooling
• LED status indicator provides clear visual feedback: engaged, disengaged, connecting, disconnecting, and alarm states
• Virtually zero voltage drop across the contacts, eliminating the need to increase alternator or charger output voltage as required with diode isolators
• Prioritises starter battery by only engaging when the starter battery reaches the connect voltage, ensuring reliable engine starting
• 16 mm (M8) long bolts allow secure connection of multiple heavy-duty cable lugs
• IP54 protection rated for dust and water spray, suitable for engine bays and exposed installations
• Low current consumption: less than 4 mA when open, 320 mA (12V) or 180 mA (24V) when closed

Built for Demanding Environments

The Cyrix-ct operates reliably in temperatures from -40 to +60 °C, making it suitable for Australian outback conditions, marine engine rooms, and cold-climate expeditions. Its compact dimensions (65 x 100 x 50 mm) and lightweight design (0.27 kg) allow flexible mounting in tight spaces. The included 1-metre control cable simplifies integration with existing wiring, while the robust M8 stud terminals accommodate heavy-gauge cables for minimal resistance.

Applications

• Caravans and motorhomes: automatically charge house batteries from the alternator while driving
• 4x4 and off-road vehicles: maintain auxiliary power for winches, fridges, and lighting
• Marine vessels: combine starter and service battery banks for efficient charging underway or at dock
• Commercial trucks and buses: manage multiple battery banks for lift gates, communications, and auxiliary equipment
• Off-grid solar systems: integrate with battery chargers to parallel charge multiple battery strings

Why Choose the Cyrix-ct Over Diode Isolators?

Diode isolators introduce a voltage drop of 0.6-0.7V, requiring higher alternator output and reducing charging efficiency. The Cyrix-ct uses a mechanical relay with negligible voltage loss, ensuring your batteries receive the full charging voltage. This leads to faster, more complete charging and longer battery life, especially critical for AGM and lithium batteries that require precise voltage regulation.

Upgrade Your Dual-Battery System Today

Experience reliable, intelligent battery management with the Victron Cyrix-ct 12/24V-230A. Whether you're building a new off-grid setup or upgrading an existing split charge system, this VSR delivers the precision and durability needed for demanding mobile and marine applications. Add it to your system now and ensure your auxiliary batteries are always ready when you need them.

Specifications