Automatic Charging Relay; Acr System Hints/Self Tests - Regal LS4 Owner's Manual

Automatic Charging Relay

The M-ACR is designed to manage the charging
current from outboard stators up to 65 amps.
It includes a start isolation feature that protects
sensitive electronics by temporarily isolating house
loads from the engine circuit during engine cranking,
protecting the house circuit from voltage spikes
and sags.
The ACR works by sensing when the voltage of
either battery rises to a level indicating that a charge
source is active (13.0 volts for 2 minutes). At that
point the ACR's contacts connect and the ACR
applies to both batteries. If the voltage on both
batteries subsequently drops to 12.75 volts for 30
seconds, the ACR disconnects and isolates the
batteries.
ACR's use a relay combined with a circuit that
senses when a charging source is being applied to
either battery. Compared to battery isolators they
create very little heat and consume little charging
energy. Note that the ACR body encompasses a
QR label which when connected through an app
will take you to the web-site where you can fi nd
detailed operation and troubleshooting information
beyond what is noted here.

ACR System Hints/Self Tests

If the ACR does not disconnect when the engine
is turned off it has not reached the low voltage
threshold to isolate the circuit. It may take several
minutes for the batteries to drop to this level.
Since the ACR uses a delay, additional time up
to 2 minutes may be required before the ACR
disconnects.
A slow fl ashing LED indicates that the start isolation
wire is energized.
A fast fl ashing LED indicates one or both batteries
are below 9.5 volts DC. Refer to the table below.
127