Isolation relay ML 500A 12V ACR

The ML 500A 12V ACR (Automatic Charging Relay) (Blue Sea Systems ML-Series ACR) is a magnetically latched (bistable) isolation relay for high charging currents. It automatically connects two large battery banks as soon as a common alternator provides charging voltage, and disconnects them again during discharge or engine start – with very low self-consumption when switched on.

Advantages

• Magnetic latching ensures very low current consumption when closed
• 500 A switching capacity for large battery banks, 300 A live switching for 10,000 cycles
• Optionally configurable start isolation protects sensitive electronics during cranking
• Optionally configurable engine isolation separates two running engines from each other, if required by the engine manufacturer
• Silver alloy contacts for reliable switching under load
• LED feedback of switching status, a remote control switch (Contura) is included

Technical Data & Compatibility

• Nominal voltage 12 V DC, control signal via stranded wire cable
• Combine voltage 13.0 V (2 min.) / 13.5 V (30 sec.), Disconnect voltage 12.75 V (30 sec.) / 12.35 V (10 sec.)
• Under-voltage lockout 9.6 V, Over-voltage lockout 16.2 V DC
• Continuous current up to 500 A with 2× 4/0 AWG wiring, Cranking current up to 1450 A (30 sec.)
• Connection studs 3/8"-16 (copper, tinned), no manual override
• Protection class IP66, ignition protected according to ISO 8846 and SAE J1171

When is the ML 500A 12V ACR the right choice?

Whenever large battery banks with high charging current requirements – for example, in larger boats or commercial vehicles – are to be charged via a common alternator. The 500 A rating and low self-consumption in continuous operation make the ML-ACR the preferred solution when standard 120 A relays are no longer sufficient.