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Victron Cyrix-ct Intelligent Battery Combiner 12/24V-120A VSR
Victron Cyrix-ct Intelligent Battery Combiner 12/24V-120A VSR
120A Continuous, Trend Detection, Bidirectional, Start Assist, IP54
Highlights:Mounting Tab: Secure mounting hole for easy installation to a flat surface,Battery 1 Stud: M8 stud for primary battery connection (Terminal 87),Battery 2 Stud: M8 stud for secondary battery connection (Terminal 30),Start Assist Pin: Spade terminal for optional start assist push button (Terminal 85),Negative Pin: Common negative spade terminal for voltage sensing (Terminal 86).
Key features: 120A continuous current rating, Bi-directional voltage sensing, Intelligent trend detection prevents unnecessary switching, IP54 protection category, Compact 46 x 46 x 80 mm dimensions.
A schematic connection diagram showing the Cyrix-ct 12/24-120 VSR installed between a vehicle alternator, a start battery, and a domestic battery bank, including the optional start assist wiring configuration. 
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DESCRIPTION
Victron Cyrix-ct 120A Intelligent Battery Combiner for Dual Battery Systems
Advanced Voltage Sensing Relay with Trend Detection for Reliable Parallel Charging
The Victron Cyrix-ct 12/24V-120A is a microprocessor-controlled intelligent battery combiner that functions as a bidirectional voltage sensitive relay (VSR). Unlike conventional split charge relays that rely on simple voltage thresholds and fixed time delays, the Cyrix-ct analyses the overall voltage trend to prevent nuisance switching. This ensures your auxiliary battery bank charges reliably from the alternator or mains charger without premature disconnection under heavy loads or reconnection when surface charge dissipates.
Engineered for 12V and 24V automotive and marine electrical systems, the Cyrix-ct auto-detects system voltage and provides a continuous current rating of 120 A, making it suitable for charging large domestic battery banks, bow thruster batteries, and other onboard equipment. Its bidirectional sensing allows the combiner to engage when either battery reaches the connect voltage, so charging sources on either side can parallel the banks automatically.
Intelligent Trend Detection Eliminates Unwanted Cycling
Standard voltage-controlled relays often disconnect a battery when a short, high-current load causes a momentary voltage dip, or fail to connect a deeply discharged bank because the voltage collapses below the disconnect threshold immediately after engagement. The Cyrix-ct’s software monitors the rate and direction of voltage change over time, reversing a previous action only if the trend has genuinely reversed. The time delay adapts based on the deviation from the trend, providing stable operation in demanding conditions.
Key Features
- 120 A continuous current rating with 180 A cranking assist for emergency parallel starts
- 12/24 V auto-ranging detects system voltage automatically, no manual configuration needed
- Bidirectional voltage sensing and dual power supply allows engagement from either battery, even if one is deeply discharged
- Start Assist function via push button or switch provides 30-second emergency parallel connection
- Over-temperature protection disengages the relay if contact temperature becomes excessive, re-engaging after cooling
- Virtually zero voltage drop across the contacts, eliminating the need to increase alternator or charger output voltage
- Prioritises starter battery by connecting auxiliary banks only after the starter reaches the connect voltage
- Compact IP54-rated housing (46 x 46 x 80 mm) withstands dust and water spray in engine bays and marine compartments
- Low power consumption: less than 4 mA when open, 220 mA (12 V) or 120 mA (24 V) when closed
- 13 mm (M6) long stud terminals allow secure connection of multiple heavy-duty cable lugs
Reliable Parallel Charging Without Voltage Loss
Diode-based battery isolators introduce a voltage drop of 0.6–0.7 V, which can prevent full charging unless the alternator or charger is voltage-boosted. The Cyrix-ct uses a high-current relay with negligible contact resistance, so your batteries receive the full charging voltage. This makes it a direct, efficient replacement for diode isolators in 12V dual battery systems and 24V marine setups.
Emergency Start Assist for Peace of Mind
If your starter battery becomes discharged or damaged, the Cyrix-ct can be manually engaged using a momentary push button or switch connected to the Start Assist terminal. The relay remains closed for 30 seconds, allowing you to draw power from the auxiliary bank to crank the engine. This feature is invaluable for remote travel, off-grid work sites, and marine applications where a flat starter battery could leave you stranded.
Designed for Harsh Environments
With an operating temperature range of -40 to +60 °C and an IP54 protection rating, the Cyrix-ct is built to perform in engine compartments, bilges, and exposed vehicle installations. The fully sealed housing resists dust ingress and water spray, while the robust M6 stud terminals accept heavy-gauge cable lugs for secure, low-resistance connections.
Typical Applications
- Charging a second battery in 4WD, caravan, and camper trailer dual battery systems
- Marine installations with separate start and house battery banks
- Bow thruster and windlass battery charging
- Commercial vehicles and agricultural machinery with auxiliary power requirements
- Off-grid solar systems where multiple battery banks need to be combined during charging
Installation and Wiring
The Cyrix-ct features clearly labelled M6 stud terminals for Battery 1 (Terminal 87) and Battery 2 (Terminal 30), plus spade terminals for the negative sensing wire (Terminal 86) and optional Start Assist switch (Terminal 85). A wiring diagram is included in the product images to guide installation. For systems requiring multiple engage/disengage profiles, consider the Victron Cyrix-i 400.
Upgrade Your Dual Battery System with Intelligent Control
Replace unreliable diode isolators and basic voltage-sensing relays with the Victron Cyrix-ct 120A Intelligent Battery Combiner. Its trend-detection logic, bidirectional sensing, and emergency start assist provide dependable parallel charging for your auxiliary batteries. Order today to ensure your onboard power system operates efficiently and reliably, wherever your journey takes you.
SKU: Vic-CYR010120011
SPECIFICATIONS
Specifications
| Victron Part Number | CYR010120011 |
|---|---|
| Model | Cyrix-ct 12/24-120 |
| Product Type | Intelligent Battery Combiner |
| System Voltage | 12/24 V Auto Ranging |
| LED Status Indication | No |
| Continuous Current | 120 A |
| Cranking Rating (5 s) | 180 A |
| Connect Voltage | From 13 V to 13.8 V and 26 to 27.6 V, with intelligent trend detection |
| Disconnect Voltage | From 11 V to 12.8 V and 22 to 25.7 V, with intelligent trend detection |
| Current Consumption When Open | <4 mA |
| Current Consumption When Closed | 12 V: 220 mA; 24 V: 120 mA |
| Operating Temperature Range | -40 to +60 °C |
| Start Assist | Yes (Cyrix remains engaged during 30 s) |
| Control Cable Included (Length 1 m) | No |
| Protection Category | IP54 |
| Weight | 0.11 kg (0.24 lbs) |
| Dimensions (H x W x D) | 46 x 46 x 80 mm (1.8 x 1.8 x 3.2 in) |
| Long Bolts | 13 mm (M6) |
| SKU: | Vic-CYR010120011 |
| Barcode: | 8719076022138 |
| Model #: | CYR010120011 |
| MPN: | CYR010120011 |
WARRANTY
Victron Energy Limited Warranty Policy
Direct Customers
Victron Energy provides the following warranty to any direct customer (OEM, distributor or dealer) in relation to any products that Victron Energy has directly sold to the direct customer. This warranty is not an end-user warranty between Victron Energy and an end-user, and end-users shall not have any rights or remedies under this limited warranty towards Victron Energy directly. The direct customer shall, in turn, ensure that the end-user is provided with a warranty identical to this warranty, subject to applicable local mandatory law.
End-Users
Victron Energy may also provide a warranty directly to end-users, in which case the below warranty conditions equally apply to such warranty. In that case, end-users shall claim their warranty at their place of purchase or through the original direct customer of Victron, which can be found through the support section on Victron’s website https://www.victronenergy.com/support. Hence, the direct customer shall on behalf of Victron Energy deal with any warranty claims made under any warranty that Victron Energy may provide directly to end-users. This support section on Victron’s website https://www.victronenergy.com/support will provide further guidance on the procedure for end-users to make a claim under this limited warranty.
If the end-user is a consumer – a natural person who is acting for purposes which are outside that person's trade, business, craft or profession – the following applies. The rights and remedies granted to the consumer under this limited warranty are without prejudice to the consumer’s statutory rights. Furthermore, the consumer is entitled by law to remedies from the seller free of charge in the event of a lack of conformity of the goods (such as repair, replacement, price reduction or rescission), which remedies are not affected by this limited warranty.
Warranty
Victron Energy warrants its products to be free from defects in workmanship and materials for a period of 5 years from the date of purchase by the original end-user, with a maximum of 66 months from the Victron Energy invoice date. Exceptions on this are: lead-acid batteries: 2 years from date of purchase by the original end-user, with a maximum of 30 months from the Victron Energy invoice date, Lithium batteries: 3 years from date of purchase by the original end-user, with a maximum of 42 months from the Victron Energy invoice date. In addition to this, proof of correct battery usage is required when making a battery warranty claim.
For a 10% surcharge on the current net price for products that came with a 5-year warranty, an additional 5 years of warranty can be purchased by Victron’s direct customers, bringing the total warranty to 10 years. Warranty extensions need to be applied for ultimately one year before the expiration of the original term. Victron may ask proof that the product was still functional at the time of purchase of the extended warranty.
During the warranty period, Victron Energy will, at its discretion, repair, replace or (partly) credit the defective product free of charge. The warranty does not include performing or reimbursing de‐installation, transportation, and re‐installation.
This warranty will be considered void if the unit has suffered any physical damage or alteration, either internally or externally, and does not cover damages arising from improper use like:
- Reversed battery polarity.
- Inadequate connection.
- Mechanical shock or deformation.
- Contact with liquid or oxidation by condensation.
- Use in an inappropriate environment (dust, corrosive vapour, humidity, high temperature, biological infestation, etc.).
- Breakage or damage due to lightning.
- Connection terminals and screws destroyed or other damages, like overheating, due to insufficient tightening.
- For any electronic breakage except due to lightning (reverse polarity, over‐voltage due to external cause), the state of the internal control diode and/or the input/output X and Y capacitors determine the warranty.
This warranty will not apply where the product has been misused, neglected, improperly installed, or repaired by anyone other than Victron Energy or one of its authorized Repair Centres. In order to qualify for the warranty, the product must not be disassembled or modified.
This warranty and our warranty obligations thereunder (repair, replacement or credit) are the direct customer’s and, if applicable, the end-user’s sole rights and remedies and our sole obligations with respect to any defective and/or non-conforming product or breach of warranty and is subject to and without prejudice to the limitations of liability in this warranty.
Victron Energy shall not be liable for damages, whether direct, incidental, special, or consequential, even caused by negligence or fault.
As a product requires service, it must be brought back to the place of purchase. In case no contact can be made with the merchant, or if he is either unable or not allowed to provide service, direct contact should be made with Victron Energy through the support section on Victron’s website.
In case Victron Energy replaces a product, it will own the replaced product. Victron Energy owns all parts removed from repaired products. Victron Energy uses new or reconditioned parts made by various manufacturers when performing warranty repairs or building replacement products.
If Victron Energy repairs or replaces a part of a product, its warranty term is not extended: the warranty will apply for the remaining term of the original warranty term. For example, if Victron Energy replaces a product with a 5-year warranty after 3 years, the warranty of this product will apply for another 2 years, with a minimum of 6 months.
All remedies and the measure for damages are limited to the above. Victron Energy shall in no event be liable for consequential, incidental, contingent or special damages, even if having been advised of the probability of such damages.
The foregoing limited warranty provided by Victron Energy is in lieu of any other warranties, express or implied arising by law, course of dealing, course of performance, usage of trade or otherwise, of any kind whatsoever including, without limitation, warranties of merchantability or fitness for a particular purpose, with respect to any product. The above is without prejudice to the arrangement for consumers detailed above.
Life Support Policy
As a general policy, Victron Energy does not recommend the use of any of its products in life support applications where failure or malfunction of Victron Energy's product can be reasonably expected to cause the failure of the life support device or to significantly affect its safety or effectiveness. Victron Energy does not recommend the use of any of its products in direct patient care. Victron Energy will not knowingly sell its products for use in such applications unless it receives in writing assurances satisfactory to Victron Energy that the risks of injury or damage have been minimized, the customer assumes all such risks, and the liability of Victron Energy is adequately protected under the circumstances.
Warranty on repairs for products outside their warranty period
The warranty period on products that are outside their warranty period and have been repaired by Victron Energy or one of the Victron Energy Repair centres is six (6) months from delivery. The same applies to spare parts and circuit boards that have been supplied or repaired by Victron Energy.
Transport
It is the responsibility of the sender to sufficiently package these products. The transport must be organized in a way to avoid any damage, especially when a single unit or heavy unit is sent.
Severability
If a part of the terms and conditions of this warranty is held invalid, void or unenforceable due to any particular national or international legislation, it shall not affect other parts of the terms and conditions of this warranty.
Applicable law
This warranty is exclusively governed by the laws of the Netherlands, to the exclusion of the UN Convention on Contracts for the International Sale of Goods.
Contact details
Victron Energy B.V. | De Paal 35, 1351 JG Almere, The Netherlands | https://www.victronenergy.com/support
