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Free shipping over $49
60-day hassle-free returns
The Cyrix is a microprocessor-controlled heavy-duty relay that automatically parallels batteries when one reaches a preset charge voltage, then disconnects when voltage drops below float. Unlike a diode isolator, a Cyrix adds no voltage drop — your alternator or charger voltage reaches the batteries unchanged — which makes it an excellent modern replacement for diode isolators.
It uses intelligent trend detection rather than a fixed time delay, so it won't nuisance-disconnect during a brief heavy load and won't fail to combine a large but discharged bank. It senses voltage on both batteries (bidirectional), has a dual power supply so it still closes if one battery is flat, and includes a Start Assist function — a push-button or switch parallels the banks for 30 seconds to jump a dead start battery in an emergency. Auto-ranging and rated IP54.
Which Cyrix do you need?
- Cyrix-ct — the standard combiner for lead-acid start/house systems. 120A (180A cranking) or 230A (500A cranking); the 230A adds an LED status indicator and includes a 1 m control cable. Auto-ranging 12/24V.
- Cyrix-i — intelligent high-current combiner, 400A (2000A peak for 1 second), with four selectable switching profiles and a micro-switch for remote monitoring. Auto-ranging 12/24V or 24/48V.
- Cyrix-Li-ct — combiner for lithium systems; parallels a lead-acid start battery and a LiFePO4 bank under VE.Bus BMS (charge-disconnect) control. 120A or 230A.
- Cyrix-Li-charge — connects a charge source to a lithium bank, enabled by the VE.Bus BMS allowed-to-charge signal.
- Cyrix-Li-load — connects loads to a lithium bank, controlled by the VE.Bus BMS allowed-to-discharge signal.
The Li versions require a VE.Bus BMS. Not sure which fits your alternator and battery chemistry? Get a custom quote or call (800) 628-6306.
Blue Marine is an authorized Victron Energy dealer — ships brand-new with the full 5-year Victron warranty, free shipping, and local pickup available.
Warranty Information
Shipping & Returns
We offer free shipping over $49. Lithium batteries & oversize items may have an applicable shipping charge.
We know returns are no fun so we aim to make the return process as hassle free as possible! We have a 60-day return policy, which means you have 60 days after receiving your item to request a return.
Lithium batteries and products with lithium batteries inside are non returnable: Due to carrier regulations surrounding the shipment of lithium batteries (classified as a fully regulated hazardous material), we are unable to accept returns unless arranged locally. We appreciate your understanding and encourage you to contact us with any questions prior to purchase.
For more information on returns, visit our return policy page.
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