Victron Cyrix-ct 12/24V 120A battery coupler isolating relay battery protection

Cyrix 120A Battery Isolator

The cyrix battery isolator is a high-performance microprocessor-controlled relay that automatically connects batteries in parallel when one of them reaches a preset voltage level (indicating that the battery is being charged) and disconnects the batteries again when the voltage drops below the maintenance voltage level (indicating that one or both batteries are currently being discharged).
cyrix battery isolators are ideal for replacing isolation diodes. Their main feature is that there is virtually no voltage drop, so the output voltage of the alternators or battery chargers does not need to be increased.

Product features

• maximum continuous current: 120 A
• allowable starting current (5s): 180 A
• suitable for 12 V or 24 V systems (automatic detection)
• virtually no voltage drop
• no D+ signal required: The Cyrix battery isolator switches depending on the battery voltage
• battery temperature protection: In case of high overload, the battery is automatically disconnected

Intelligent battery monitoring to prevent unwanted switching

Some battery isolators (also called voltage-controlled relays or split charge relays) disconnect a battery when a short but high-amperage load occurs. Sometimes a battery isolator will also not connect a large but discharged battery bank because the DC voltage immediately drops below the disconnect threshold after the batteries are connected. The software of the Cyrix-ct 12/24 takes on more functions than simply connecting and disconnecting based on the battery voltage and with a fixed time delay.
The Cyrix-ct 12/24 monitors the general trend (voltage is rising or falling) and only reverses a previous action if the trend has reversed during a certain period. The time delay depends on how much the voltage deviates from the trend.

No voltage drop

cyrix battery isolators are ideal for replacing isolation diodes. Their main feature is that there is virtually no voltage drop, so the output voltage of the alternators or battery chargers does not need to be increased.

Bidirectional voltage detection and power supply from both batteries

The Cyrix measures the voltage of the two connected batteries. It therefore also switches on if, for example, the additional battery is being charged by a battery charger. The Cyrix-ct 12/24 has a dual power supply.
It therefore also closes even if the voltage on one of the batteries is too low to power the Cyrix.
To prevent accidental operation during installation or if one of the batteries has been disconnected, the Cyrix-ct 12/24 does not close if the voltage on one of the two battery connections is below 2 V (12 V battery) or 4 V (24 V battery).

Protection against overheating (e.g. due to prolonged overload)

The Cyrix disconnects if the contact temperature is too high and reconnects after the temperature has dropped.

The Cyrix can also be switched on via a push button (Cyrix remains in operation for 30 seconds) or via a switch to manually connect the batteries in parallel. This is particularly useful in an emergency if the starter battery is discharged or damaged.

Technical information