Victron Cyrix-i 24/48V 400A Battery Combiner Isolation Relay Battery Protection

Cyrix-i Intelligent Battery Combiner

The Cyrix battery combiner is a high-performance, microprocessor-controlled relay that automatically connects batteries in parallel when one of them reaches a predefined voltage (indicating that the battery is being charged) and disconnects them when the voltage drops below the float voltage (indicating that one or both batteries are being discharged).
Cyrix battery combiners are excellent for replacing isolating diodes. Their main feature is that there is virtually no voltage drop, so the output voltage of AC generators or battery chargers does not need to be increased.

Product Features

• maximum continuous current: 400 A
• permissible starting current (1s): 2000 A
• suitable for 24 V or 48 V systems (automatic detection)
• virtually no voltage drop

New: innovative battery monitoring prevents unwanted switching operations

With some battery control relays, short-term high currents can trigger disconnection processes. It can also happen that a large but empty battery bank cannot be connected because the voltage drop during connection causes the switch-off threshold to be undershot.
The software stored in the Cyrix-i does not only refer to voltage values and fixed time intervals. Rather, the Cyrix-i takes into account the trend (voltage/time – curves) and only intervenes if the trend changes over a certain time interval. The time delay is proportional to the voltage deviation from the trend. In addition, four different switching/time curves can be set.

Automatic range selection for 12/24V

Cyrix-i automatically detects the system voltage present.

No voltage loss

The Cyrix-i battery control is the alternative to isolating diodes. Since there is virtually no voltage loss, the usual increase in charging voltage at the alternator or charger to compensate for losses is eliminated.

Priority switching for the starter battery

Typically, the alternator is connected directly to the starter battery. The house battery, possibly the bow thruster battery and others are connected via Cyrix-i devices. Only when the starter battery has reached the appropriate voltage does the Cyrix-i connect the other batteries for parallel charging.

Bidirectional voltage measurement and power supply

Cyrix-i measures the voltage values of the connected battery banks. It therefore typically also reacts when the house battery is charged by a charger. The Cyrix-i has a dual power supply. It therefore also works when one of the connected batteries has undervoltage for Cyrix-i operation.
To avoid unwanted switching operations during installation or after disconnecting the battery, Cyrix-I will not switch if the voltage value of one of the two battery terminals drops to less than 4V (24V battery) or 8V (48V battery).

Parallel connection in an emergency

The Cyrix-i can also be switched on via a push button (the Cyrix-i then remains switched on for 30 seconds). There is also a switch for manual parallel connection of the batteries. This is particularly helpful if the starter battery should be empty or damaged in an emergency.

Documents & Downloads

• Datasheet