ML-ACR Automatic Charging Relay with Manual Control, 500A
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BLUE SEA SYSTEMSML-ACR Automatic Charging Relay with Manual Control, 500A


In stock online.
Model # 14122147 | Mfg # 7622UPC # 632085076221


ML-ACR Automatic Charging Relay with Manual Control, 500A

Name Value
Amperage 700 Amps at 12 Volts DC
ISO Approved ISO 8846 and SAE J1171
Mounting Hardware Mounting Screws (Sold Separately)
Type Charging Relays
Warranty Details Lifetime

Product Overview

500 Amp magnetic latching (bi-stable) Automatic Charging Relay will automatically combine batteries during charging and isolate batteries when discharging or when starting engine.

The ML-ACR (Magnetic Latch-Automatic Charging Relay) and ML-RBS (Remote Battery Switch, sold separately), when paired, provide complete battery management of large battery banks with the push of a button. In addition to automatically sharing the charge from an engine’s alternator between the start and auxiliary battery, the ML-ACR control switch combines batteries momentarily to assist with starting in the event an engine battery is low.

With the optional Blue Sea Systems 9160 Paralleling Link Bus (sold separately), multiple remote battery switches can be easily connected to the ML-ACR for a complete remote battery management subsystem.

An automatic charge relay (ACR) performs several tasks. It combines two battery banks to charge them from a single source, and isolates each bank as required to prevent accidental discharge and protect sensitive circuits. The Blue Sea Systems ML-series ACR adds some additional features and allows the user to choose how the battery banks are isolated.

Blue Sea Systems designed the ML-Series heavy duty Automatic Charge Relay to manage large battery banks with push-button convenience. The ACR is mounted close to batteries and battery switches to reduce heavy cable runs and simplify installation. An Ignition protection rating allows the ACR to be installed in the engine room of gasoline powered boats. An included remote switch controls the ACR and requires as little as 20 AWG wire; saving time and expense of running heavy gauge cable.

The ML-Series offers some additional control at the remote switch. The included Contura style switch allows the user to select ON, AUTO, and OFF: to combine the two banks in emergency situation, select automatic mode, and turn off or isolate the ACR. Users can set the system up for Start Isolation to isolate the house bank and protect sensitive electronics or Engine Isolation to isolate the engines to protect sensitive engine electronics.

Key Features

  • 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
  • Allows two battery banks to be efficiently charged from a single charging source without external regulators or isolators
  • Dual sensing; senses charge in each battery bank
  • Start Isolation or Engine Isolation allow uses to select bank to be isolated during current spikes to protect sensitive electronics or engine control systems
  • Ignition protected; can be installed in engine rooms of gasoline powered boats
  • Operated using remote switch; eliminates long heavy gauge cable runs
  • Remote switch (included) provides emergency combine feature to start the engine or make a radio call Manual lever provides control if power to remote switch has been compromised
  • LED indicators on switch designate mode of operation
  • Can be easily connected to ML series battery switches using link bus plates
  • Lifetime warranty

ACR Specifications

  • Nominal voltage: 700V
  • Engine Isolation: Yes
  • Operating Current: 13mA
  • Operating Current when changing state: <7.0A
  • Live Current Switching: 300A @ 12V DC
  • ontinuous Rating: 500A
  • Intermittent Rating: 700A
  • Cable Size to Meet Rating: 4/0 AWG
  • Terminal Stud Size: 3/8"
  • Weight: 04 lbs.
  • Approvals: Meets ISO 8846 and SAE J1171 external ignition protection requirements, CE marked, Rated IP66

Relay Contact Position

  • Combine 30 sec: 5V
  • Combine 90 sec: 0V
  • Open 10 sec: 35V
  • Open 30 sec: 75V
  • Open High: 2V


Wiring Diagram

Dimensional Drawing

ACR Troubleshooting Guide

 WARNING: Cancer and Reproductive Harm -


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