Description
xVictron Cyrix-ct 12/24V 120A Intelligent Battery Combiner
The Victron Cyrix-ct is a microprocessor-controlled battery combiner designed for 12V and 24V systems carrying up to 120A continuous current. It automatically connects batteries in parallel when one battery is being charged, then disconnects them when charging stops, protecting the starter or primary battery from being drained by auxiliary loads. It is suited to marine, vehicle and off-grid installations where two battery banks need to be managed without manual switching.
Key Features
- Microprocessor-controlled logic connects and disconnects battery banks automatically based on voltage thresholds, with no manual intervention required.
- Rated for 120A continuous current on 12V or 24V DC systems, making it suitable for high-demand auxiliary loads.
- Connects batteries in parallel when the system voltage rises to a charge level, and disconnects when voltage drops back to a resting level, preventing cross-discharge.
- Compact and lightweight at 0.12 kg, allowing installation in tight spaces such as engine bays, caravans and boat bilge areas.
- Compatible with standard lead-acid, AGM and gel battery chemistries commonly used in dual-battery systems.
- Solid-state design with no moving parts, reducing the risk of mechanical failure in vibration-prone environments.
- SKU: CYR010120011 | GTIN: 8719076022138
Product Overview
The Cyrix-ct operates by monitoring the voltage of both battery banks. When the voltage on either bank rises above the connect threshold (indicating a charge source is active), the unit closes its internal relay to join the banks in parallel. Both batteries then charge simultaneously from the available source, whether that is an alternator, shore power charger or solar charge controller. When the charge source is removed and voltage falls back below the disconnect threshold, the relay opens and the banks are isolated again.
This behaviour protects the starter battery in vehicle and marine applications. If the auxiliary bank is heavily discharged, it cannot pull down the starter battery because the combiner only connects the banks during active charging. The voltage thresholds are pre-set by Victron and are appropriate for standard lead-acid chemistry. The "ct" designation indicates this unit is intended for use with conventional alternators and battery chargers, as opposed to the Cyrix-Li variants designed for lithium battery systems.
The unit requires a connection to an ignition or charge-detect signal in some installation configurations, allowing it to respond correctly when an alternator is the charge source. Wiring is straightforward, with clearly labelled terminals for both battery banks and the control input.
Specifications
- SKU: CYR010120011
- System voltage: 12V or 24V DC
- Continuous current rating: 120A
- Weight: 0.12 kg
- GTIN: 8719076022138
- Compatible battery chemistries: Lead-acid, AGM, Gel
Applications
- Dual-battery systems in motorhomes and campervans, keeping the starter battery isolated from leisure loads.
- Marine installations where a dedicated engine-start battery must be protected from auxiliary drain.
- Agricultural and commercial vehicles with high auxiliary electrical loads running from a secondary battery bank.
- Off-grid cabins or small solar installations using two battery banks that need automatic parallel charging.
- 4x4 and overland vehicles with auxiliary battery setups for winches, lighting or refrigeration.
What Is Included
- 1 x Victron Cyrix-ct 12/24V 120A intelligent battery combiner
Installation Notes
Installation should be carried out by a qualified auto-electrician or marine electrician familiar with dual-battery wiring. Ensure the cable sizing to and from the unit is rated for at least 120A and that appropriate fusing is fitted on both battery connections as close to each battery terminal as practical. The Cyrix-ct is designed for lead-acid, AGM and gel battery systems only. Do not use this unit with lithium (LiFePO4) battery banks without first confirming compatibility, as lithium systems have different voltage profiles that may require a Cyrix-Li variant instead.
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:
- 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.