Description
xVictron Cyrix-i 12/24V 400A Intelligent Battery Combiner
The Victron Cyrix-i is a microprocessor-controlled battery combiner designed to connect two battery banks in parallel when both are being charged, and to separate them when charging stops. It is suited to marine, vehicle, and off-grid installations where a starter battery and a service battery must be kept isolated under load but charged simultaneously from a single source.
Key Features
- Rated at 400A continuous current, suitable for high-demand 12V and 24V systems.
- Microprocessor-controlled switching logic monitors battery voltage and connects banks only when a charge source is detected, preventing the starter battery from being drained by service loads.
- Automatic operation with no manual intervention required once installed.
- Compatible with lead-acid battery chemistries including AGM, gel and flooded types.
- Compact and robust construction with a weight of 0.9 kg, suitable for installation in confined spaces.
- Operates across both 12V and 24V systems without reconfiguration.
- Voltage-sensing logic prevents premature connection during engine cranking, protecting the service bank from voltage dips.
Product Overview
The Cyrix-i works by continuously monitoring the voltage of both battery banks. When the voltage on either bank rises above a set threshold (indicating a charge source such as an alternator or shore power charger is active), the unit connects the two banks in parallel so both charge simultaneously. When the voltage drops back below the threshold, the banks are separated, ensuring the starter battery retains enough charge for engine starting regardless of how deeply the service bank has been discharged.
Unlike a simple relay or diode-based isolator, the Cyrix-i uses microprocessor logic to apply time delays and hysteresis to its switching decisions. This prevents rapid cycling caused by voltage fluctuations and avoids connecting a discharged bank to a healthy one at the wrong moment. The 400A rating means it can handle the full output of most vehicle alternators and battery chargers without becoming a bottleneck in the charging circuit.
The unit is designed to be wired directly between the positive terminals of the two battery banks. It requires no external control signal and draws negligible standby current, making it well suited to installations where the system may sit unused for extended periods.
Specifications
- SKU: CYR010400000
- Voltage compatibility: 12V and 24V
- Continuous current rating: 400A
- Weight: 0.9 kg
- GTIN: 8719076022251
Applications
- Marine vessels with separate starter and service battery banks charged from a single alternator.
- Motorhomes and campervans requiring isolation between the vehicle starter battery and the leisure battery bank.
- Commercial vehicles with auxiliary power systems that must not compromise engine starting reliability.
- Off-grid cabins or static installations where two battery banks are charged from a single charger or solar system.
- Agricultural and plant machinery with high-current dual-battery configurations.
What Is Included
- 1 x Victron Cyrix-i 12/24V 400A intelligent battery combiner
Installation Notes
The Cyrix-i should be installed by a qualified electrician or marine electrical engineer familiar with high-current DC systems. Connections must be made with appropriately rated cable and correctly sized fusing on each battery bank. Ensure both battery banks share a common negative before installation. The unit is not suitable for use with lithium battery chemistries unless the lithium battery management system is confirmed compatible with voltage-based combiners.
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.