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Victron Cyrix-Li-Intelligent Charge Relay 12/24V-120A
BMS-Controlled 120A Charge Relay for LiFePO4 - 46x46x80mm IP54
DESCRIPTION
Victron Cyrix-Li-Charge 12/24V-120A: Intelligent Charge Relay for LiFePO4 Battery Systems
Precision Charge Control for Lithium Battery Protection
The Victron Cyrix-Li-Charge 12/24V-120A is a specialised intelligent charge relay designed to integrate seamlessly with Victron VE.Bus BMS and LiFePO4 lithium batteries. It acts as a critical secondary protection layer, automatically connecting and disconnecting charging sources to prevent cell overvoltage and over temperature conditions. Unlike generic relays, the Cyrix-Li-Charge responds instantly to BMS signals, ensuring your expensive lithium battery bank remains within safe operating limits at all times.
Engineered for 12V and 24V DC systems, this relay handles continuous currents up to 120A, making it suitable for high-power chargers and alternators. Its intelligent logic monitors both the BMS control input and battery voltage, providing automated reconnection only when conditions are safe. This reduces the risk of battery damage from faulty chargers or unexpected voltage spikes, a common issue in mobile and off-grid installations.
How the Cyrix-Li-Charge Protects Your Investment
In a Victron lithium system, the VE.Bus BMS serves as the primary safeguard. However, not all chargers can be directly controlled by the BMS. The Cyrix-Li-Charge bridges this gap by acting as a controllable switch. When the BMS detects an imminent cell overvoltage or high temperature (above 50°C), it sends a signal to the Cyrix, which disengages immediately—cutting off the charging source within milliseconds. This rapid response prevents thermal runaway and extends battery lifespan.
After disconnection, the relay intelligently manages reconnection. It waits for the BMS signal to return high and verifies that the charger output is above 13.7V (12V system) or 27.4V (24V system). A 3-second delay ensures stability before re-engaging. If repeated faults occur, the delay extends to 10 minutes, preventing rapid cycling that could stress system components. Additionally, if battery voltage drops below 13.5V (27V for 24V) for an hour, the relay disengages to avoid unnecessary drain.
Key Features at a Glance
- Instant BMS-driven disconnection for overvoltage and over temperature protection
- 120A continuous rating at 12V/24V, with 40A breaking capacity at 48V
- Automatic reconnection logic with progressive delays to prevent cycling
- Low power consumption (<4mA when open) ideal for energy-conscious systems
- Compact, robust design (46x46x80mm, 0.11kg) with IP54 protection
- Built-in transient voltage suppression to protect against inductive spikes
- Clear status LED for quick operational diagnostics
Seamless Integration with Victron Energy Systems
The Cyrix-Li-Charge is purpose-built for Victron's ecosystem, connecting directly to the VE.Bus BMS control output. It requires a minimum of 2V on its battery terminal to operate, ensuring it remains open if accidentally disconnected from the battery—a safety feature that prevents uncontrolled charging. The relay's 3/8"-16 (Approx. M10) stud terminals accommodate heavy-duty lugs up to 4/0 AWG (approx. 95mm²), ensuring secure, low-resistance connections for high-current applications.
For installers, the integrated mounting tabs and pre-drilled holes simplify fixed installations in battery compartments, engine bays, or electrical cabinets. The IP54 rating provides protection against dust and water splashes, making it reliable in marine, RV, and off-grid environments where conditions can be harsh.
Applications: Where Precision Charging Matters
This relay is essential for any Victron lithium setup where charging sources cannot be directly managed by the BMS. Typical use cases include:
- Marine and RV electrical systems with high-output alternators or shore power chargers
- Off-grid solar installations using MPPT controllers that lack BMS communication
- Backup power systems where generator or grid chargers need automated disconnect
- Industrial battery banks requiring fail-safe charge termination
By isolating the charger during fault conditions, the Cyrix-Li-Charge prevents overcharging that could lead to cell degradation or safety hazards. It also eliminates the need for manual intervention, allowing unattended systems to operate safely.
Why Choose the Cyrix-Li-Charge Over Generic Relays?
Standard automotive relays lack the intelligence to interpret BMS signals or monitor voltage thresholds. They simply switch on or off, offering no protection against overvoltage or temperature extremes. The Cyrix-Li-Charge, in contrast, actively communicates with the BMS and applies conditional logic to ensure charging only occurs when safe. This reduces the risk of battery failure, which can be costly and dangerous in lithium systems.
Additionally, the built-in transient voltage suppressor protects against voltage spikes that occur when the relay disconnects under load—a common cause of contact welding in inferior relays. This extends the relay's operational life and maintains system integrity.
Installation and Compatibility Notes
The Cyrix-Li-Charge is designed for use with Victron LiFePO4 batteries and the VE.Bus BMS. It is not a standalone battery protect device; for load disconnection, consider the Victron BatteryProtect. Always ensure proper fusing and cable sizing according to system current. The relay's control input engages when high (approx. battery voltage) and disengages when free-floating or pulled low, making it compatible with standard BMS outputs.
For systems requiring combined charging and load control, the Cyrix-Li-ct (battery combiner) or Cyrix-Li-load (load disconnect) variants may be more appropriate. Contact our team for assistance with system design if you're unsure which model suits your application.
Secure Your Lithium Battery System Today
Protect your investment with the Victron Cyrix-Li-Charge 12/24V-120A. Whether you're upgrading an existing installation or building a new off-grid power system, this intelligent relay provides the precision control needed for safe, reliable lithium charging. Order now to ensure your battery bank operates within safe limits, every cycle.
SKU: Vic-CYR010120430
SPECIFICATIONS
Specifications
| Model | Cyrix-Li-Charge 12/24-120 |
|---|---|
| System Voltage | 12/24 V |
| Continuous Current And Breaking Capacity At 12 V Or 24 V | 120 A |
| Breaking Capacity At 48 V | 40 A |
| Connect Delay | 3 s |
| Connect Voltage | 13.0 V (12 V), 26.0 V (24 V) |
| Minimum Battery Terminal Voltage | 2 V |
| Control Input | Engages when the control input is high (appr. battery voltage); disengages when the control input is left free floating or pulled low. |
| Charger Check Interval When Engaged | 1 hour |
| Current Consumption When Open | <4 mA |
| 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) |
| SKU: | Vic-CYR010120430 |
| Barcode: | 8719076022183 |
| Model #: | CYR010120430 |
| MPN: | CYR010120430 |
WARRANTY
Victron Energy Limited Warranty Policy
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 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 end user, with a maximum of 30 months from the Victron Energy invoice date, Lithium-ion batteries; 3 years from date of purchase by the end user. In addition to this proof of correct battery usage is required when making a battery warranty claim.
During this period, Victron Energy will, at its option, repair or replace 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: • Reverse of battery polarity. • Inadequate connection. • Mechanical shock or deformation. • Contact with liquid or oxidation by condensation. • Use in inappropriate environment (dust, corrosive vapor, humidity, high temperature, biological infestation...). • Breakage or damage due to lightning. • Connection terminals and screws destroyed or other damages, like overheat, due to insufficient tightening. • For any electronical breakage except due to lightning (reverse polarity, over‐voltage due to external cause), the state ofthe internal control diode and of the inputs/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 else than Victron Energy or one of its authorized Qualified Service Partners. In order to qualify for the warranty, the product must not be disassembled or modified.
Repair or replacement are our sole remedies and Victron Energy shall not be liable for damages, whether direct, incidental,special, or consequential, even caused by negligence or fault.
Victron Energy owns all parts removed from repaired products. Victron Energy uses new or reconditioned parts made by various manufacturers in performing warranty repairs and building replacement products. If Victron Energy repairs or replaces a part of a product, its warranty term is not extended. In case of replacement the new component has a warranty of 6 months, without effect on the initial warranty period. All remedies and the measure for damages are limited to the above. Victron Energy shall in no event be liable for consequential, incidental, contingent orspecial damages, even if having been advised of the probability of such damages. Any and all other warranties expressed or implied arising by law, course of dealing, course of performance, usage of trade or otherwise, including but not limited to implied warranties of merchantability and fitness for a particular purpose, are limited in duration to a period of two (2) years from the date of purchase.
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 the Victron Energy's product can be reasonably expected to cause 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.
As a product requires service, it must be brought back to the place of purchase. In case no contact can be taken with the merchant, or if he is either unable or not allowed to provide service, direct contact should be taken with Victron Energy.
Warranty on Repairs The warranty period on products or on printed circuits boards repaired by Victron Energy as well as on printed circuit boards for replacement is 6 months from delivery 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 set out above 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 remaining.
For Australia only Our goods come with guarantees that cannot be excluded under the Australian Consumer Law. You are entitled to a replacement or refund for a major failure and compensation for any other reasonably foreseeable loss or damage. You are also entitled to have the goods repaired or replaced if the goods fail to be of acceptable quality and the failure does not amount to a major failure.
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