Description
xCyrix-Li-ct 12/24V-120A Intelligent Li-ion Battery Combiner
The Victron Cyrix-Li-ct is a microprocessor-controlled battery combiner designed specifically for lithium-ion battery systems operating at 12V or 24V. It replaces a conventional VSR (voltage-sensitive relay) in installations where a Li-ion battery is combined with a starter or auxiliary lead-acid battery. The unit is controlled directly by the battery management system (BMS), ensuring the combiner only connects batteries when the BMS permits it.
Key Features
- Rated at 120A continuous current, suitable for demanding charging and load-sharing applications.
- Compatible with both 12V and 24V systems, covering the most common marine, vehicle and off-grid voltage configurations.
- Controlled via a dedicated BMS charge-disconnect or load-disconnect signal, not by voltage alone, preventing unsafe charge states.
- Microprocessor-controlled logic ensures the combiner responds correctly to BMS commands rather than relying on simple voltage thresholds.
- Compact and lightweight at 0.12 kg, making it straightforward to install in tight battery compartments or switchboards.
- Designed to work within Victron's broader ecosystem, integrating with Victron BMS units and compatible third-party BMS outputs.
Product Overview
Conventional voltage-sensitive relays connect batteries based on voltage levels alone. In a lithium-ion system, this approach is inadequate: a Li-ion battery can reach a high voltage while still being in a condition where further charging is unsafe. The Cyrix-Li-ct addresses this by taking its switching signal directly from the BMS charge-disconnect or load-disconnect output. When the BMS signals that charging should stop, the Cyrix-Li-ct opens immediately, isolating the Li-ion bank from the alternator or charger regardless of the measured voltage.
The "ct" designation indicates the unit is controlled by the BMS rather than operating autonomously on voltage detection. This makes it the correct choice wherever a Li-ion battery is being combined with a conventional lead-acid starter battery, for example in a motorhome, boat or commercial vehicle where the engine alternator charges both banks simultaneously. The 120A rating covers most alternator outputs in these applications without requiring an oversized unit.
At 12V or 24V compatibility, the same unit covers a wide range of system designs without needing separate part numbers for each voltage. Installation requires a BMS with a suitable charge-disconnect or load-disconnect output. The Cyrix-Li-ct is not a standalone voltage-sensing relay and will not function correctly without a controlling BMS signal.
Specifications
- SKU: CYR010120412
- System voltage: 12V or 24V
- Continuous current rating: 120A
- Control input: BMS charge-disconnect or load-disconnect signal
- Weight: 0.12 kg
- GTIN: 8719076034339
Applications
- Marine installations combining a Li-ion house bank with a lead-acid engine starter battery.
- Motorhomes and campervans with a lithium leisure battery and a vehicle starter battery charged from the same alternator.
- Commercial vehicles requiring controlled split-charging between Li-ion and lead-acid banks.
- Off-grid systems where a Li-ion battery bank is combined with an auxiliary battery and BMS-controlled isolation is required.
- Any 12V or 24V dual-battery system where a BMS must have authority to disconnect the combiner.
What Is Included
- 1 x Cyrix-Li-ct 12/24V-120A battery combiner unit
Installation Notes
The Cyrix-Li-ct must be wired to a compatible BMS charge-disconnect or load-disconnect output to function correctly. It will not operate as a standalone voltage-sensing relay. Installation in marine, vehicle and off-grid battery systems should be carried out by a qualified electrician or accredited installer familiar with lithium battery systems. Ensure all cabling is rated for the continuous 120A load and that appropriate fusing is fitted on both battery connections in accordance with wiring regulations. Verify BMS signal compatibility before installation.
Return Policy
xWe offer a 14-day, no-quibble returns or replacement policy because we want you to be totally satisfied with your purchase.
If you are unhappy in any way with your purchase, you can return it for a refund or a replacement, as long as you return it in the same condition as it arrived (original/undamaged packaging and product) and within 30 days of receiving it. We will pay for your return postage on a faulty item as long as you send it using Royal Mail 2nd class recorded delivery (for EU or International Shipments, you have to use our UPS account, we will provide you with a return label)
Please keep in mind the following:
- Non-faulty items returned after 14 days and/or not in their original, undamaged packaging can only be exchanged for store credit - 15% off the items returned.
- Items returned within 14 days but not in their original and undamaged packaging will also incur a -15% charge per package.
- If you return an item that doesn't adhere to our returns procedure or doesn't include a returns form, you may be liable for a £10 administration fee
- Individual items from a bundle can't be returned, refunded or exchanged. If you want a refund/credit/exchange for a bundle, all items must be returned to us.
Before you return your item, please make sure that:
- You follow our returns process (outlined below)
- The goods and packaging are undamaged
IMPORTANT: We need to be able to identify an item with your order. We can only do this if you follow our returns process. Please do not send us items back that do not follow this process as they cannot be identified properly and will not be replaced or refunded.
What delivery method do I need to use when returning an item?
You must send the goods back to us via Royal Mail 2nd class recorded delivery. Refunds on faulty items returned are reimbursed within 5 working days.
Can I return just one item from multiple purchases?
Yes. Once you start the returns process you will go to a page that will allow you to choose which items you want to be replaced or refunded.
Returning faulty goods
If your item is faulty, you need to follow the returns policy, where you will be able to state that it’s faulty. The product will then arrive at our warehouse for testing.
If your purchase is not within 14 days
You can still exchange your item for a different product or for credit to use on the Voltacon Solar or Ledison-led-lights.co.uk websites (-15% from the credit amount).
Returns outside of the 14-day period do not qualify for the free returns policy.
Returning an item within the warranty
If you have a warranty and want to return a faulty item, you just need to follow our standard returns process. When we receive your item, we will then check that it’s within warranty and for any faults before arranging a replacement.