Victron Cyrix-ct 12/24V 230A wiring diagram

The Cyrix-ct 12/24-230 automatically parallels two batteries in a common-negative 12 V or 24 V system. The installation manual, PDF page 1, gives its wiring, timing and LED indications. This is the standard ct model, not the similarly named Cyrix-Li-ct with a BMS control input.

A closed relay directly joins battery positives. It provides neither a lithium charging profile nor alternator current limiting. Confirm that the banks may share a charging source before connecting them.

A and B represent the two full-current battery-positive studs. The real device also needs its BAT− control connection to common negative. Its optional Start Assist connection takes battery positive through a switch; the manual diagram includes a 0.1 A fuse in this small command circuit.

Momentary start assist closes the relay for 30 seconds; a maintained switch can hold the banks together while closed. The control harness cannot carry cranking current. The family datasheet specifies M8 main bolts and a supplied one-metre control cable for the 230 A model.

The unit is rated 230 A continuous and 500 A for five seconds for cranking. The installation text requires a series fuse chosen for the cable, not exceeding 230 A; its illustrated circuit uses 225 A. These are compatible statements: 230 A is the ceiling, not a requirement to find or fit that exact fuse value.

Both batteries can supply fault current, so review the protection of both connecting runs. Select the actual fuse's DC voltage and interrupt capacity for the bank, and retain separate protection for downstream loads. No tightening torque was found in the reviewed manual/datasheet; confirm the supplied hardware requirement before assembly.

Charging either bank can trigger connection because sensing is bidirectional. Connection and release follow voltage trends with variable delays; a brief voltage change does not necessarily mean a fault. Overtemperature opens the contacts and normal operation resumes after cooling.

Unlike the 120 A unit, this model has an LED. The manual distinguishes engaged, disengaged, connecting, disconnecting and alarm patterns. Verify those states, the negative reference and optional start assist during commissioning. The drawing omits these control connections, the two-bank charging configuration and relay timing; it is a main-current terminal map rather than a complete control schematic.