Victron Cyrix-Li Intelligent Battery Combiners For LFP Systems

Victron Energy's Cyrix-Li series combiners are similar to the Cyrix-Ct series, but have additional capabilities for use with a lithium battery management system (BMS).

All Cyrix battery combiners have microprocessor-controlled heavy-duty relays that automatically connect batteries to charging sources or loads depending on incoming charge voltage (Li-Charge and Li-Ct only) and on signals from the BMS. There are three variations.

Cyrix-Li-CT
The functionality of the Cyrix-Li-CT is analogous to the Cyrix-CT.

The Cyrix-Li-CT will parallel connect a starter battery and alternator to a LiFePO4 battery:
- if the Charge Disconnect output of the VE.Bus BMS is high, and
- if it senses 13.4V (resp. 26.8V) or more on one of its power terminals.

The Cyrix-Li-CT will disengage immediately:
- when its control output becomes free floating, signalling cell over voltage or cell over temperature, and/or
- when battery voltage drops below 13.2V.

Start assist function: a short positive pulse will close the relay during 30 seconds. A built-in transient voltage suppressor will limit the voltage spike that may occur when the Cyrix suddenly disengages due to cell overvoltage or over temperature.

Cyrix-Li-Charge
The Cyrix-Li-Charge will connect a battery charger with 3 seconds delay:
- if the Charge Disconnect output of the VE.Bus BMS is high, and
- if it senses 13.7V (resp. 27.4V) or more on its battery charger connection terminal, and
- if it senses 2V or more on its battery terminal (the Cyrix will remain open, if not connected to the battery). The Cyrix-Li-Charge will disengage immediately whenever its control input becomes free floating, signalling cell over voltage or cell over temperature. In general a cell over voltage alarm will reset shortly after charging has been stopped. The Cyrix will then reconnect the charger after a delay of 3 seconds. After two attempts to reengage with 3 seconds delay, the delay increases to 10 minutes. Whenever battery voltage is less than 13.5V (resp. 27V), the Cyrix will disengage with a delay of 1 hour.

Note 1: In case of zero discharge current, or a small discharge current, the Cyrix will not disengage shortly after the charger has been switched off and/or disconnected, because battery voltage will remain higher than 13.5V.
Note 2: If, after the Cyrix has disengaged, the output of the battery charger immediately increases to 13.7V or more, the Cyrix will reengage, with 3 seconds delay.

Cyrix-Li-Load
The Cyrix-Li-Load will disengage when its control input becomes free floating, ie: the BMS directs it to disconnect. If the battery voltage recovers after disconnecting (which will happen when no other loads are connected to the battery), the output of the BMS will become high and the Cyrix will reengage after 30 seconds. After 3 attempts to reengage, the Cyrix will remain disengaged until battery voltage has increased to more than 13V (resp. 26V) during at least 30 seconds (which is a sign that the battery is being recharged).
Alternatively, a Smart BatteryProtect can be used (advantage: very low power consumption).

All Cyrix combiners / isolators have the following features:

No voltage loss
Cyrix battery combiners are excellent replacements for diode isolators, the main advantage being that there is virtually no voltage loss.

12/24V auto ranging
The Cyrix battery combiners automatically detects system voltage and adjusts to 12V or 24V. Please note that system nominal voltage must be common on both sides - it is not possible to use a Cyrix with a 12V start battery and a 24V house bank, for instance.

Reliability
All Victron Energy products (except batteries) come with a 5 year worldwide warranty, supported by an international network of service points and dealers.