Victron Energy Cyrix Battery Combiner (12/24/48V, 120A–400A)

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.