The Victron Cyrix-Li-load is a microprocessor-controlled load relay built for lithium battery systems running at 12V or 24V. It disconnects non-essential loads when battery voltage drops to a critical level, protecting the battery from deep discharge. Rated at 230A continuous, it handles demanding DC load circuits in marine, vehicle and off-grid installations.

Key features of this battery isolator switch

• Continuous current, 230A, suited to high-draw DC load circuits.
• System voltage, compatible with 12V and 24V lithium battery systems, with thresholds calibrated for Li chemistry.
• Automatic disconnect, microprocessor logic monitors battery voltage and opens the load circuit at a programmable low-voltage threshold.
• Automatic reconnect, loads reconnect once the battery recovers to a safe voltage, with no manual intervention needed.
• Weight, 0.3 kg, compact enough for confined installations.
• BMS integration, works alongside Victron Battery Management Systems and can be controlled via a BMS load disconnect signal.

How it protects lithium batteries

Unlike a standard battery combiner, the Cyrix-Li-load exists to shed loads rather than join battery banks. When voltage falls below the disconnect threshold, the relay opens and isolates the load circuit. This matters for lithium chemistries, which can be damaged or made unsafe if discharged below their minimum cell voltage.

At 230A the unit handles substantial DC loads: inverters, winches, bow thrusters and other high-current consumers. The microprocessor applies hysteresis to avoid rapid cycling at the threshold boundary. Where a Victron BMS is fitted, the relay can also accept a direct load disconnect signal from it, giving the BMS control over load shedding independent of voltage alone.

Applications

• Load protection on lithium battery banks in marine and narrowboat systems.
• Non-essential load shedding in off-grid cabins and mobile off-grid vehicles.
• Motorhome and campervan DC systems with lithium batteries powering high-current appliances.
• Overland and expedition vehicles with lithium house battery banks.
• Any 12V or 24V lithium installation needing automatic low-voltage load disconnect.

What's in the box

• 1 x Cyrix-Li-load 12/24V-230A intelligent load relay

Installation notes

Fitting should be carried out by a qualified electrician or experienced marine/vehicle installer. The relay must be wired in series with the load circuit, not the battery charging circuit. Cable sizing should suit the 230A continuous rating, with suitable fusing fitted close to the battery. When integrating with a Victron BMS, refer to the BMS wiring documentation to configure the load disconnect signal correctly.