Victron Cyrix-ct 12v / 24v 120A Voltage Sensitive Relay (Batt Combiner)

  (12 Reviews)
Price:  £44.16   (£36.80 Exc. VAT)

Product code:  P01250
Brand:  Victron



7 in stock

The 12v / 24v 120A Cyrix CT battery combiner from Victron Energy is a feature-packed intelligent split charge solution for charging your leisure battery from your alternator and ensuring you never accidentally flatten your starter battery. More commonly known as a voltage sensitive (or sensing) split charge relay, this unit will automatically connect your starter and leisure batteries when a charging voltage is sensed and will automatically disconnect them when it senses the voltage drop away 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.

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).

Another useful function is the emergency start assist. If the starter battery has become flattened and you wish to use the leisure battery to start the vehicle, you can manually close the relay using a momentary switch wired to terminal 85 (relay remains closed for 30 seconds).

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)
  • 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.)


For more information on our battery-battery chargers and VSRs check out our YouTube Video 
  • Voltage rating: 12V or 24V DC
  • Current rating (continuous): 120A
  • Current rating (peak): 180A 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: 220mA (12V) / 120mA (24V)
  • Main terminal size: 2 x M6x13mm studs
  • Emergency start assist terminal size: 2 x 6.3mm male blades
  • Operating temperature: -40 to +40°C
  • Ingress Protection rating: IP54
  • Fixing hole dia: 6mm
  • Overall dimensions: 46 (W) x 46 (D) x 80 (H) mm

Part Number:  CYR010120011

Bar Code:  8719076022138

Average Rating (12 Reviews):  
Write a Review and share your opinions!

Split charge relay
Wednesday, 4 May 2022  | 

Received the product within a few days, came with instructions and cable, easy to follow, and has been working hard everyday since I've had it, I've had no issues so far A1 for me,

Monday, 21 June 2021  | 

I have used these before, they are great.

Great piece of kit
Tuesday, 1 June 2021  | 

I have now installed 3 of these cyrix battery combiners on campervans. They are great little units, solid victron quality, simple and seemingly very reliable. 2 of them I installed with the 12 volt planet kit which had everything I needed to get the job done. The latest installation was on my own campervan to make use of all my excess solar generation. I'll no doubt be placing another order very soon.

Device works well. Prompt delivery
Wednesday, 24 February 2021  | 

Device works well. Prompt delivery

Wednesday, 7 March 2018  | 

Great product well made came on time

First class
Tuesday, 25 July 2017  | 

Upgraded charging system big improvement no lag until charge kicks in as there was before with old simple relay system

Good service & Product
Saturday, 20 May 2017  | 

Delivered quickly & does what itsays!

Easy to fit
Tuesday, 16 August 2016  | 

Ran engine when fitted and charge was very good. Not been on a long cruise yet but will soon know

Compact solution
Tuesday, 14 June 2016  | 

Very pleased with this compact relay, easy to mount and connect up.

Checked with some voltage logging (using a Raspberry Pi) and it certainly works. Batteries are connected within a few seconds of engine starting, as the alternator provides charge. Both batteries are also connected with the engine off when the leisure battery is on charge, as soon as the voltage rises enough.

The ability to add a manual switch to allow for "jump starting" from the leisure battery is a good idea, I hope I'll never need to use it.

Wednesday, 18 May 2016  | 

Simple to fit bit of kit and it works

Read all 12 customer reviews...


Victron is an extremely well-known and respected brand with an enormous amount of experience in the automotive, industrial, off-grid, marine, energy-storage and telecoms sectors. It is at the cutting edge of power management technology, offering a range of innovative and highly reliable products for every commercial and leisure application.

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