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Blue Sea 7610 SI-ACR Automatic Charge Relay with Start Isolation 12/24V DC 120A

Automatically combines batteries during charging, isolates batteries when discharging and when starting engines.

Features:

Protects sensitive electronics by temporary isolation of house loads from engine circuit during engine cranking
Designed for 12 or 24 Volt systems
12/24 Volt auto ranging voltage input
Hermetically sealed contacts/vapor-proof
Ignition protected-safe for installation aboard gasoline powered boats
Supports high-output alternators up to 120 Amperes
Dual sensing

Optional Features:

Start Isolation allows temporary isolation of House loads from Engine circuit during engine cranking to protect sensitive electronics from sags and spikes. See Instructions.
Remote LED remotely indicates ACR states - requires optional LED

An ACR senses when the voltage of either of the batteries rises to a level indicating that a charge source is active (13.0 V for 2 minutes). The ACR′s contacts then connect and the ACR applies the charge to both batteries. If the voltage on both of the batteries subsequently drops to 12.75 V for 30 seconds, the ACR will disconnect, isolating the batteries.

An ACR does not direct the charge to the battery that "needs it the most" or has the lowest terminal voltage. If there is a charge present on either battery, indicated by a high enough voltage, the ACR will combine the batteries.

An ACR will work with all charge sources, including an alternator, AC charger, or solar panel. However, low current charge sources might not produce the voltage rise required to force the ACR to combine.
Note: The BS 7610 SI-ACR automatically combines batteries during charging, isolates batteries when discharging and when starting engines. The addition of a Blue Sea Dual Circuit Plus^TM Battery Switch will simplify the switching of two batteries to OFF or ON while still providing battery isolation between the engine and auxiliary battery. The Combine function can be used to parallel the batteries in the event of a low engine battery.