Blue Sea Systems ML-Series Automatic Charging Relays: Powerful 500A Magnetic Latching Relays for Advanced Battery Management

The Blue Sea Systems ML-Series Automatic Charging Relays are high-capacity 500A magnetic latching (bi-stable) relays designed for advanced battery management. These relays automatically combine batteries during charging and isolate them during discharging and engine starting, optimizing battery performance and ensuring protection for sensitive electronics. The magnetic latching (ML) design draws minimal current in the ON state, enhancing energy efficiency.

The relays offer configurable Start Isolation (SI) to temporarily isolate house loads from the engine circuit during cranking, protecting delicate electronics from voltage sags. Additionally, the Engine Isolation (EI) function can be configured to isolate two engines while both are running, safeguarding engine electronics and maximizing alternator output. For added safety and control, the manual override knob allows for operation with or without power and includes a LOCKED OFF setting for secure servicing.

These relays sense charging on two battery banks and provide an LED output for remote indication of switch state, compatible with optional LED or Remote Control Contura Switch with integrated LED. The 3/8"-16 tin-plated copper studs ensure maximum conductivity and corrosion resistance, while the 7/8" stud length accommodates multiple cable terminals. Durable one-piece stainless steel flange nuts guarantee secure connections, and silver alloy contacts ensure high reliability for live switching.

Products on this page may be available in bulk, please call for a quote

• ML-Coil Function: Bi-Stable. Includes Remote Control Contura Switch
• Switching Cycles: 100,000 Cycles.
• Live Current Switching: 300A @ 12V DC-10,000 Cycles.
• Continuous Rating: 500A.
• Terminal stud: 3/8"-16 (M10).
• Control Circuit Connections: Tinned Wire or Deutsch DTM / Amphenol ATM Cable End options
• Manual Control Options: 75985 and 75993
• CE marked, ISO 8846 and SAE J1171 external ignition protection requirements. IP66 - protected against powerful water jets.
• Charging relay accessories can be found here.
• Download data sheet here.
  Download instructions here.
  Download wiring diagram here.