Victron Cyrix-Li-charge 24/48V-120A intelligent charge relay

The Victron Energy Cyrix-Li-Charge 24/48V-120A is an essential accessory for 12V and 24V LiFePO4 battery systems. With its capacity to handle currents up to 120A, it serves as a perfect complement to the VE.Bus BMS, acting as a battery switch for loads that cannot be directly controlled by the VE.Bus BMS.

General function of the Cyrix battery coupler:

The device, a powerful microprocessor-controlled relay, automates the parallel connection of batteries when a specific voltage level is reached, indicating the state of charge, and disconnects them again as soon as the voltage drops below a critical level, indicating discharge. The Cyrix battery coupler effectively replaces isolating diodes by operating without any voltage loss, meaning no adjustment of the output voltage of generators or chargers is necessary.

How the Cyrix-Li-Charge 24/48V 120A works:

The Cyrix-Li-Charge is activated to connect a battery charger under the following conditions:

• The "Charge Disconnect" output of the VE.Bus BMS is active,
• A voltage of at least 13.7 V (or 27.4 V or 54.8 V) is measured at the battery charger connection,
• A voltage of 2 V or more is detected at the battery terminal (remains inactive when not connected to the battery).
• The device immediately disconnects if the control output enters the "free-floating" state or if a cell overvoltage or overheating condition is detected. After charging is stopped and the cell overvoltage alarm is reset, the Cyrix reconnects. After two reconnection attempts within 3 seconds, the delay changes to 10 minutes. The Cyrix shuts down if the battery voltage drops below 13.5 V, with a delay of one hour.

Important instructions:

If there is no or minimal discharge current, the Cyrix remains inactive because the battery voltage exceeds the 13.5 V threshold. If the battery charger voltage immediately returns to 13.7 V or higher after a disconnect, the Cyrix reactivates the connection after a short 3-second delay.