Switching Solutions for Multiple Battery Banks

April, 18 2008

The Dual Circuit Plus™ Battery Switch is an ideal solution for switching multiple battery banks. One switch simultaneously switches two battery banks while isolating the battery banks from each other. Battery isolation protects the Start battery from being discharged by the many House loads such as refrigerators, stereos, and lights, while preserving it for starting the engine. Battery isolation also protects sensitive electronics from voltage spikes and sags that may occur in the Start circuit during engine starting.

Dual Circuit Plus™ Battery Switch positions:

  • Set to ON. Simultaneously switch two isolated circuits. Current flows from the House battery to the House circuit, and from the Start battery to the Start loads.
  • Set to COMBINE BATTERIES. In the event that more starting power is required, the two battery banks can be combined. The operator simply turns the switch knob to the COMBINE BATTERIES position. Current flows from both House and Start batteries to both House and Start loads.

Advantages over selector switches. The Dual Circuit Plus™ Battery Switch is preferable to a traditional selector battery switch in the following ways:

  • Isolation of circuits is not possible with a selector switch. Both House and Start circuits are combined in 1, 2, or BOTH selector switch positions. Therefore, sensitive electronics are always exposed to voltage sags and spikes caused by engine starting, and lighting and entertainment loads can discharge battery banks which might be needed for starting.

  • Connect deep cycle battery to House loads, connect Start battery for starting. Modern battery banks typically include batteries specific to the task. The House battery often is a deep cycle battery designed for long term discharge, the Start battery often is optimized for starting with a high capacity to deliver peak currents. The Dual Circuit Plus™ Battery Switch maintains these associations of batteries to circuit, and discourages operating batteries routinely in the combined position which can result in discharging the Start Battery Bank with house loads.
  • Ease of operation. The Dual Circuit Plus™ Battery Switch, because of its simple ON-OFF operation, is far more intuitive to use than a selector switch. Two or three Dual Circuit Plus™ Battery Switches used to control multiple battery banks are much more intuitive to use than two or three selector switches.

Multiple Battery Bank Solutions. Multiple Dual Circuit Plus™ Battery Switches can be used to switch systems with multiple battery banks. Click on the links below to view schematic diagrams for 2, 3, and 4 battery bank applications.


Note: Only one side/stud terminal of some of the Dual Circuit Plus™ Battery Switches in this application are used. See notes on schematic diagrams for details.

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