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The 12v / 24v 230A Cyrix ct battery combiner from Victron Energy is a feature-packed intelligent split charge solution for parallel charging of a second battery. More commonly known as a voltage sensing (or sensitive) split charge relay, this unit will automatically connect your starter and auxiliary batteries when a charging voltage is sensed from the alternator (or any other charging source such as a mains charger or solar panels) and will automatically disconnect them when it senses the voltage drop again when the engine is turned off. This isolates the batteries when they are not charging so your starter battery cannot be drained by your domestic circuits and vice versa.

This relay features voltage trending software to overcome short-term fluctuations in voltage levels and prevent unwanted disconnection (e.g. when first connected to a leisure battery with very low charge and/or of a very high capacity, the resultant voltage drop across the starter battery can be significant and can trigger a false disconnect in some other voltage sensing relays - sometimes referred to as 'chatter' as the relay quickly opens and closes repeatedly). 

Supplied with a control cable terminated with a waterproof Superseal connector for convenient connection to the terminals for earth and Start Assist. The Start Assist feature is useful if the starter battery has become flattened and you wish to use the leisure battery to start the vehicle (by wiring the red cable to a momentary switch you can manually close the relay to briefly connect the batteries).

PLEASE NOTE: These relays are not suitable for vehicles with 'smart' or 'intelligent' alternators. As a guide this applies to vehicles having engines that comply with Euro5 emissions standards and onward, often also incorporating regenerative braking (if in doubt please consult your vehicle manufacturer to confirm). If your vehicle has a smart alternator then you will need to use a battery-to-battery charger instead of a VSR.


  • 12V or 24V operation (auto detection)
  • Voltage trending software
  • Dual sensing (also allows leisure to starter battery charging, e.g. when using a battery charger or solar panels)
  • Over-current protection
  • Over-temperature protection (automatic re-engage once cooled)
  • Emergency start assist
  • Virtually zero voltage drop and low standby current draw
  • No alternator connection required
  • Sealed for use in harsh environments (marine use, vehicle engine bays etc.)
  • Superseal control cable for convenient connection
  • LED status indication

Victron Energy Cyrix-ct 12v / 24v 230A Voltage Sensitive Relay (Batt Combiner)

SKU: CYR010230010
Sales Tax Included |
    • Voltage rating: 12V or 24V DC
    • Current rating (continuous): 230A
    • Current rating (peak): 500A for 5s
    • Connect voltage: 13.3-13.8V / 26-27.6V (software dependent)
    • Disconnect voltage: 11.0-12.8V / 22 -25.7V (software dependent)
    • Standby current draw: 4mA max.
    • Operation current draw: 320mA (12V) / 180mA (24V)
    • Main terminal size: 2 x M8x16mm studs
    • Emergency start assist terminal size: Superseal connector
    • Control cable length: 1m
    • Operating temperature: -40 to +40°C
    • Ingress Protection rating: IP54
    • Fixing hole dia: 8mm
    • Overall dimensions: 100 (W) x 50 (D) x 65 (H) mm
    • Part Number:  CYR010230010
    • Bar Code:  8719076022206
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