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New ACROur Friends at Blue Sea Systems has raised the bar yet again when it comes to battery isolation with the introduction of a new feature for its already popular ACR devices. The info below describes it all:


Timer Disconnect


  • ·         12V signal triggers relay to connect battery power to devices
  • ·         When signal is removed the timer is activated and will disconnect devices after a preset time
  • ·         Timer ranges from 15 minutes to 4 hours


Low Voltage Disconnect


  • ·         Senses low battery voltage and automatically disconnects devices
  • ·         Low voltage setting can be used in conjunction with Timer Disconnect. Low voltage will disconnect devices prior to preset time to preserve battery power


Automatic Charging Relay


  • ·         Automatically combines two batteries when charging, and isolates them when discharging
  • ·         Single side sensing design only monitors the voltage of the start battery
  • ·         Ideal for auxiliary batteries that are AGM or significantly larger than the start battery




  • ·         12V signal will connect or disconnect relay without any time delay

The compelling new feature here is the timer disconnect, which gives the boat owner an additional element of control over battery charging and use cycles.

The specifications for this new unit are shown here:

Nominal Voltage 12V DC
Amperage Operating Current 175mA (closed)
4mA (open)
Terminal Stud Torque 140 in-lb (15.82 Nm)
Continuous Rating 120A
Intermittent Rating 210A (5 Min)
Cable Size to Meet Ratings 1 AWG (50mm²)
Charge Sense Connect 13.0V (3 sec)
Charge Sense Disconnect 12.75V (10 sec)
Disconnect Time 5 sec, 15 min, 30 min, 1 hr, 1.5 hr, 2hr, or 4hr
Input Voltage Range 9.5-16V
Low Voltage Disconnect 11.0V (10 sec)
11.5V (10 sec)
12.0V (10 sec)
Maximum Cable Size 1/0 AWG (50mm²)
Terminal Ring Diameter Clearance 1.12in (28.45 mm)
Terminal Stud Size 3/8″-16 (M10)
Over Voltage Lockout 16.0V (5 sec)

Of course these units are rated for ignition protection so they are not at issue being installed in engine room spaces on gasoline fueled boats or battery storage areas.

I found the price point rather interesting as well. With a retail price of $135, these units are only about $15 more expensive than an ancient tech Cole Hersee diode type battery isolator with no inherent intelligence built in. Seems like low money for some exceptional features that will go a long way toward keeping your batteries happy.



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