The Victron Cyrix-ct 12/24V-230A  battery combiner (MPN CYR010230010R) is a high-performing microprocessing-controlled relay that automatically switches batteries parallely when a certain predefined voltage is reached (which shows that the battery is charged).
It separates the batteries when voltage falls below the trickle charge value (which shows that one of the batteries is discharged). Cyrix battery combiners are an ideal replacement for common isolators. Their main characteristic is that there is nearly no voltage loss.
That means that the AC-generator's or battery charger's output voltage does not need to be increased.

Important details:

• 230A constant current
• 500A peak-current (5s)
• 12V/24V operation voltage (auto-detection)
• MPN: CYR010230010R

Intelligent battery monitoring to prevent unwanted switching
A battery combiner (also called voltage-controlled relay or split-charge relay) disconnect batteries when there is a short but high-ampere load. Sometimes a battery bank is not connected because its DC-voltage instantly falls below the disconnection-threshold.

The Cyrix-ct 12/24's software does more than only connecting or disconnecting depending on the battery voltage and with a certain time-delay. It observes the general tendency (voltage goes up or down) and only returns earlier measures if the tendency turns within a certain period of time.
Time-delay is depending on how much the voltage deviates from the tendency.

Long binding posts to connect more than one cable
Cyrix 12/24-120: 13 mm (M6) Cyrix 12/24-230: 16 mm (M8)

LED-status-display
LED-status-display (only Cyrix 12/24 230)
LED on: connected - LED burns for 10s: disconnected
LED burns for 2s: connecting - LED flashes in a 2s-interval: disconnecting
LED flashes in a 0.25s-interval: alarm (overheating, voltage >16V, both batteries < 10V, one battery < 2V (x2 for 24V batteries)

The Cyrix battery combiner is an alternative to isolator diodes. As there is barely any voltage loss an increase of the charging voltage of battery charger or generator is not needed for compensation.

Prioritizing of the starter battery
Normally the AC-generator is connected directly to the starter battery. The supply battery or thruster battery on a boat and others are connected via a Cyrix. Only when the starter battery has reached a certain voltage the other batteries are connected for parallel charging.

Bidirectional voltage measuring and power supply
The Cyrix measures the voltage values of connected battery groups. It therefore reacts only if the supply battery is charged via a battery charger.
The Cyrix has a double power supply. It also works if one of the batteries does not have enough voltage for Cyrix-operation.

To avoid unwanted switching during installation or after unplugging the battery connector it will not switch when one of the battery connection falls under 2V (12V battery) or 4V (24V battery).

Parallel connection in case of an emergency (Start Assist)
The Cyrix can also be activated via a button (stays activated for 30s). Additionally there's a button for parallel connection of the batteries. This comes in handy when the starter battery is empty or defective.

Delivery scope:
1x Victron CYR010230010R Cyrix-ct 12/24V-230A battery combiner
1x Data cable for Cyrix-ct 12/24-230, 1m
1x Manual