Regal 3300 Owner's Manual page 123

Never replace a failed fuse without first correcting the
problem. Failure to make necessary corrections may
create a dangerous electrical situation that could result in
death or serious injury.
When leaving the vessel for extended periods of time it is recommended
to deactivate each of the battery switches. Even with both switches
in the "off " position, the automatic bilge pump and stereo memory
remain energized.
Voltage Sensitive Relay Module (VSR)
Located next to the battery switches on either side of the battery
management panel are 2 voltage sensitive relay modules. The purpose
of the VSR is to protect the battery circuit from being discharged.
Also, when the engine batteries are fully charged it can send current
to the house battery.
When the engine cranking batteries rise above 13.7 volts DC the VSR
switches to charge (cranking and house) both batteries simultaneously.
When the battery voltage drops to 12.8 volts DC the VSR disengages.
This VSR capability is known as "dual sense" technology. It permits
the VSR to sense the voltage of all batteries that the unit is connected
between. If one of the batteries is receiving a charge the VSR will close
by paralleling both battery banks to charge the house battery along with
the engine cranking batteries.
If the VSR senses the engine batteries are being discharged at a fast rate
it will open and will not allow those batteries to be overly discharged
to the point that the engines will not crank.
An example of the above situation would be if the vessel was stationary
at sea for an extended period with various electronic and entertainment
equipment energized along with the engines off the battery (ies) would
normally discharge.
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WARNING
Systems
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