Blue Sea Systems
Blue Sea ML-ACR 7622 wiring diagram
12 V ML-ACR with manual override. Automatically combines charging banks; optional start or engine isolation requires separate control wiring. The 500 A continuous rating requires two 4/0 AWG cables per stud; 300 A live switching at 12 V.
Wiring diagram
How the ML-ACR is wired.
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Cable sizing for this example
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Installation notes
Before you install.
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Verified against the manufacturer's documentation (rev. 990180180 Rev.005), checked 2026-10-01. Manufacturer documentation →
Which ML-ACR is covered?
7622 is the 12 V ML-ACR with a manual override knob. The family installation manual, pages 1–4, distinguishes it from the 24 V 7623 and versions without manual control. It automatically joins two battery banks when charging voltage is present on either bank. It is a combiner, not a DC-DC charger or lithium cell-management system.
Which wires carry battery current?
The drawing's A and B are the interchangeable high-current studs joining the two battery-positive circuits. The small harness wires operate the relay and indication; none substitutes for a battery cable. The required black harness lead connects to DC negative.
The remote-control red lead goes to the common of the control switch. The combine position applies DC positive through 2 A protection; isolate applies DC negative. The yellow lead is the remote indicator connection. The supplied sustained switch and permitted momentary alternatives have different operating behavior: use the appropriate diagram and insulate unused harness leads individually.
How do automatic and isolation modes work?
For this 12 V model, page 1 specifies combining above 13.5 V for 30 seconds or 13.0 V for 90 seconds. It separates below 12.35 V for 10 seconds or 12.75 V for 30 seconds, with under/overvoltage lockouts. Charge detection is bidirectional, so house-bank charging can also join the starter bank.
Brown, green and orange are isolation inputs. Page 3 offers start isolation or engine isolation, not both simultaneously. Start inputs use signals positive only during cranking, through 2 A inline fuses; engine-isolation inputs use the engine-running signal. The same colors cannot be wired by assumption from another ML product.
What qualifies the 500 A rating?
The manual's cable table gives 500 A continuous with two 4/0 AWG cables at each stud; a single 4/0 cable corresponds to 300 A and 2/0 to 225 A. Its 300 A live-switching rating is a different limit. Stud torque is 140 in-lb (15.8 N·m) maximum.
Place battery-circuit protection according to the actual charging/cross-connect duty; the manual's cranking exception is not a general exemption for house feeders. The drawing omits harness wiring, control fuses, remote switch and isolation logic. Check manual override, automatic operation and the LOCK OFF position during commissioning; a control command alone is not physical isolation for servicing.
Technical reference
Specifications and terminal map.
Check the model, ratings and connection points against your own unit before choosing installation hardware.
Catalog specification
12 V ML-ACR with manual override. Automatically combines charging banks; optional start or engine isolation requires separate control wiring. The 500 A continuous rating requires two 4/0 AWG cables per stud; 300 A live switching at 12 V.
Connection limits are listed in the terminal map. Use the manufacturer's documentation for the full specifications.
Terminal map
Catalog connection points, current direction and planning limits. Check the manufacturer's pinout and connector ratings before installation.
A
neutral · input
B
neutral · output
Sources and sizing method
Equipment specifications. Model details, ratings and terminal roles come from the catalog. Check your unit’s label and current manufacturer documentation for its exact revision.
Example sizing. Cable labels apply to the connected example, not a fixed cable size for this component. Set your actual equipment, current, lengths and installation conditions in Crimp before choosing hardware.
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