Description
xVictron Cyrix-i 24/48V 400A Intelligent Battery Combiner
The Victron Cyrix-i 24/48V-400A is a microprocessor-controlled battery combiner designed for 24V and 48V systems requiring high-current parallel charging between two battery banks. It replaces conventional diode-based isolators and voltage-sensing relays, eliminating the voltage drop and heat losses associated with those approaches. Suitable for marine, vehicle, off-grid and industrial applications where reliable split-charge management is required.
Key Features
- Rated at 400A continuous current, suitable for high-demand 24V and 48V battery systems.
- Microprocessor-controlled logic monitors battery voltages and connects banks only when charging conditions are met, preventing unwanted discharge between banks.
- Operates across both 24V and 48V nominal system voltages, making it compatible with a wide range of battery configurations.
- No voltage drop across the combiner when closed, unlike diode-based isolators which introduce a 0.6V to 0.7V loss.
- Automatic disconnect when voltage drops below threshold, protecting the starter or primary battery bank from being drained by auxiliary loads.
- Compact and robust construction with a weight of 0.9 kg, suitable for installation in confined spaces.
- Compatible with lead-acid battery chemistries including AGM, gel and flooded types.
Product Overview
The Cyrix-i works by continuously monitoring the voltage of both battery banks. When the voltage on either bank rises above a preset threshold (indicating that a charger or alternator is active), the Cyrix-i closes its internal relay and connects the two banks in parallel. This allows both banks to charge simultaneously from a single source. When the voltage drops back below the disconnect threshold, the relay opens and the banks are isolated again.
At 400A, this unit is rated for systems with high charging currents, such as those fed by large alternators or multi-stage battery chargers. The 24/48V dual-voltage compatibility means the same unit can be used across different system architectures without needing separate part numbers for each voltage. The absence of a voltage drop across the device (when compared to diode isolators) means charger voltage settings do not need to be compensated, and battery charging accuracy is maintained.
The Cyrix-i range is designed to work alongside Victron chargers, inverter/chargers and BatteryProtect devices, though it functions independently of any specific Victron ecosystem and can be integrated into third-party systems.
Technical Specifications
| Specification | Value |
| SKU | CYR020400000 |
| System Voltage | 24V / 48V |
| Continuous Current Rating | 400A |
| Weight | 0.9 kg |
| GTIN | 8719076022305 |
Applications
- Split-charge systems on commercial vehicles, coaches and HGVs with 24V electrical systems.
- Marine vessels with separate starter and house battery banks at 24V or 48V.
- Off-grid installations where a generator or solar charger feeds multiple battery banks.
- Industrial and telecoms backup power systems requiring isolated battery banks with automatic parallel charging.
- 48V electric vehicle auxiliary systems requiring battery bank management.
What Is Included
- 1x Victron Cyrix-i 24/48V-400A intelligent battery combiner
Installation Notes
Installation should be carried out by a qualified electrician or marine/vehicle electrical specialist familiar with high-current DC systems. At 400A, correct cable sizing, fusing and terminal torque are critical for safe operation. Ensure the unit is mounted in a ventilated location away from flammable materials. For off-grid solar installations, installation by a qualified professional is strongly recommended. Always follow Victron's wiring guidelines and local electrical regulations.
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.