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Blue Sea ML-ACR Automatic Charging Relay

SKU# BS7623
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Blue Sea ML-ACR Automatic Charging Relay may require an additional to 2 days to ship.


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Item# 7623

500 Amp magnetic latching (bi-stable) relay automatically combines batteries during charging and isolates batteries when discharging and when starting engine.


  • Manual control switch provides an added level of safety allowing control with or without power, and offering LOCK OFF capability for servicing
  • Includes ML-Series Remote Control Contura Switch PN 2146
  • Automatically manages the charging of two large battery banks
  • Allows paralleling of battery banks for emergency starting
  • 500 Ampere continuous rating to support high-output alternators
  • Magnetic Latch (ML)—ACR draws very low current (<40mA to monitor terminal voltage) in the "ON" or "OFF" states, and draws moderate current for very short time when changing state
  • Dual sensing—senses charge on both battery banks
  • Start Isolation (SI)—can be configured for temporary isolation of House loads from Engine circuit during engine cranking to protect sensitive electronics
  • Engine Isolation (EI)—can be configured for isolation of two engines while both are running to protect engine electronics and maximize alternator output
  • Senses charging on two battery banks
  • LED output to remotely indicate when batteries are combined, isolated, in voltage lockout, or in Start or Engine isolation
  • 3/8"-16 tin-plated copper studs for maximum conductivity and corrosion resistance
  • 7/8" (22mm) stud length accepts multiple cable terminals
  • Silver alloy contacts provide high reliability for switching live loads
  • Label recesses for circuit identification


  • Control Circuit Connection:Tinned Wire
  • Nominal Voltage:24V DC
  • Manual Control:Yes
  • Engine Isolation: Yes
  • Mounting10
  • Start Assist Yes
  • Start Isolation Yes
  • Amperage Operating Current13mA
  • Amperage Operating Current when changing state<7.0A
  • Terminal Stud Torque140 in-lb (15.82 Nm)
  • Continuous Rating 500A
  • Intermittent Rating 700A (5 min)
  • Cranking Rating 30 sec 1450A DC
  • Minimum Operating Temperature-10° C
  • Maximum Operating Temperature60° C
  • Cable Size to Meet Ratings4/0 AWG x 2
  • Live Current Switching300A 12V DC
  • Stud MaterialTinned Copper
  • Switching Cycles100000
  • Terminal Ring Diameter Clearance1.12in (28.45 mm)
  • Terminal Stud Length1.50in (38.1 mm)
  • Terminal Stud Size3/8" - 16 (M10)
  • Wire Size20 AWG

Relay Contact Position

  • Combine 30 sec27.0V
  • Combine 90 sec26.0V
  • Open 10 sec24.7V
  • Open 30 sec25.5V
  • Open High32.4V
  • Weight2.10lb (0.95 kg)