Victron Cyrix-ct 12/24V Battery Combiner

The Victron Cyrix-ct 12/24V is a sophisticated, microprocessor-controlled smart relay engineered to automate the connection and isolation of multiple battery banks. By replacing outdated diode isolators, which inherently suffer from voltage drop, the Cyrix-ct provides a direct, zero-loss electrical path. This ensures your alternators and chargers deliver the full, necessary voltage to your batteries, maximizing charging efficiency and battery lifespan.

Designed for reliability in marine and automotive environments, the Cyrix-ct uses intelligent trend monitoring rather than simple fixed timers. It intelligently analyzes voltage fluctuations to prevent unnecessary cycling and ensures both banks are connected only when optimal charging conditions exist. Whether you are managing a dual-battery setup in a campervan or a marine vessel, this device provides a seamless, "set-it-and-forget-it" power distribution solution.

Because the Cyrix-ct makes its connect/disconnect decision from a rolling trend in battery voltage rather than a single instantaneous reading or a fixed timer, it avoids the nuisance switching that plagues simple voltage-sensitive relays under fluctuating engine RPM or intermittent charge sources like solar. Once the starter battery voltage indicates the alternator or another charge source is active, the relay closes to parallel the banks; when voltage drops back down, indicating the engine has stopped, it opens again to protect the starter battery from being drained by house loads.

Available in two continuous current ratings: the 120A model mounts in a compact IP54-rated enclosure suited to an engine bay or battery compartment, ideal for standard dual-battery setups. The 230A model shares the same auto-ranging 12/24V, zero-voltage-drop design in a larger IP54-rated housing sized for higher continuous current - a better fit for larger house battery banks, bigger inverters, or twin-alternator setups where the 120A relay would be marginal. Both avoid the charging losses of a diode isolator entirely.

Features

Zero-Loss Charging Performance

Unlike traditional diodes, the Cyrix-ct introduces no voltage drop. This guarantees that your auxiliary battery receives the full charging voltage, essential for proper multi-stage charging.

Smart Trend Detection Algorithms

Utilizes intelligent trend analysis to differentiate between temporary voltage drops caused by high-current loads and genuine battery discharging, preventing nuisance disconnection.

Bidirectional Voltage Sensing

Continuously monitors both connected battery banks. If either the engine-side or house-side battery is receiving a charge, the relay engages to keep both banks topped up.

Integrated Start Assist

Features a dedicated "Start Assist" override. With a simple external switch, you can manually bridge the batteries for 30 seconds to jump-start your vehicle if the starter battery has failed.

Dual-Power Reliability

Even if one battery is completely depleted, the unit is powered by both banks, ensuring that the relay will still engage as soon as a charging voltage is applied.

Automatic 12/24V Recognition

Self-detects system voltage upon startup, allowing for a mistake-proof installation in both standard 12V and 24V vehicle electrical architectures.

Specifications

Datasheets and Manuals