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The 3103 is a 300A integrated solenoid and control module for 28V systems. The unit features a bi-stable solenoid that can remain open or closed without a coil current draw. The unit can be utilized in 4 different modes of operation based on settings of jumpers external to the unit.

1. Unidirectional Battery Separator:
This mode is used to charge two battery banks from one power source. In this mode, the unit monitors the “main” battery bank. When the main battery bank voltage is above the connect threshold, the solenoid connects the two banks together. When the main battery bank voltage drops below the disconnect threshold, the solenoid is opened. In this mode, the connect threshold is usually set to a voltage that is only reached when the charging system is operational. This will cause the solenoid to only close when the charging system is operational, charging both banks of batteries.

The disconnect voltage may be set one of two ways:
1 Near the full charge resting voltage of the batteries. This will cause the solenoid to be opened shortly after the engine is stopped. This will preserve 100% of the starting battery capacity for engine cranking.
2 Below the full charge resting voltage of the batteries. Setting the disconnect voltage lower will result in delaying the opening of the solenoid until some of the charge is removed from the starting battery. This will result in a longer life in the auxiliary battery and the ability to carry the auxiliary load for a longer period of time. In this mode the manual override can be used to provide jump starting from the auxiliary battery.

2. Bi-directional Battery Separator:
This mode is used to charge two battery banks from two sources. In this mode, both battery banks are monitored. If either battery bank is above the connect threshold the unit will close the solenoid. If the batteries are below the disconnect threshold the unit will open the solenoid. The voltage settings for the bidirectional battery separator remain the same as the unidirectional battery separator.

3. Low Voltage Disconnect (LVD)
In this mode, the unit monitors the battery bank voltage. When the battery bank voltage is above the connect threshold, the solenoid closes, powering the load. When the battery bank voltage drops below the disconnect voltage, the unit opens the solenoid, removing power from the load. In this mode, the connect threshold is usually set to a voltage that is only reached when the charging system is operational. The disconnect threshold is set to a voltage that leaves sufficient charge in the batteries to crank the engine.

4. Isolator / Interconnect Mode:
This mode is used to charge two battery banks from one power source. This mode provides the advantages of both the isolator charging system and the battery interconnect.

For the Technical Data Sheet click here (PDF)