Victron Cyrix-Li-Ct 12/24v-120a

The Cyrix-Li-Ct 12/24v-120a battery coupler from victron Energy (mpn cyr010120412) for 12v and 24v LiFePO4 batteries or lead-acid starter batteries. It can work with a maximum current of 120a and is, among other things, an ideal complement to the ve.Bus bms as a battery switch for those loads that the ve.Bus bms cannot switch independently.

Function of the Cyrix battery coupler in general

The Cyrix-Li-Ct 12/24v-120a is a high performance microprocessor controlled relay that automatically connects batteries in parallel when one of them reaches a predetermined voltage value (indicating that the battery is charging) and, disconnects the batteries again when the voltage drops below the float voltage value (indicating that one or both batteries are being discharged). Cyrix battery couplers are excellent for replacing isolation diodes. Their main feature is that there is virtually no voltage loss, so there is no need to increase the output voltage of the alternators or battery chargers.

Operation of the Cyrix-Li-Ct 12/24v 120a

The operation of the Cyrix-Li-Ct 12/24v 120a is the same as that of the Cyrix-Ct.

The Cyrix-Li-Ct connects a lead-acid starter battery and a LiFePO4 battery:

1. when the output "Charge Disconnect" of the ve. Bus bms is high
2. when it measures 13.4 v (or 26.8 v) or more at its current terminals

The Cyrix-Ct will shut down immediately:

1. when its control output reaches the "free floating" (open circuit) state
2. when its control output indicates cell overvoltage or cell overtemperature
3. when the battery voltage drops below 13.2 v

Start Assist function: a short positive pulse closes the relay for 30 seconds (see figure on page 2). A built-in TvS diode limits the voltage spike that can occur when the Cyrix suddenly shuts down due to a cell overvoltage or overtemperature

important technical features

• Manufacturer part number: cyr010120412
• Continuous current and cut-off current: 120a
• for 12v and 24v battery voltage
• works with LiFePO4 or lead-acid starter batteries

Cyrix-Li-Ct as a perfect complement to the ve.Bus bms

A key piece of protection for victron LiFePO4 batteries is the ve.Bus bms. However, not all loads or chargers can be controlled directly via the ve.Bus bms. To switch off such loads or chargers, several ve.Bus bms controllable Cyrix switches are available.

Scope of delivery:

1x victron Energy cyr010120412 Cyrix-Li-Ct 12/24v-120a battery coupler
1x user manual