What Is a Single Throw Double Pole Switch on a Boat?
August 27, 2023 · 4 min · 4K views
What this video covers
A single-throw double-pole battery switch allows boaters to manage two separate battery banks—typically a starter battery and a house battery—using one control.1:29 This switch configuration features three distinct modes: off, on, and combine.1:38 In the off position, both engine and house loads disconnect from their respective batteries.1:50 In the on position, the switch connects engine loads to the starter battery and house loads to the house battery, isolating the two systems.1:55 The combine mode links all batteries and loads together, providing an emergency backup to start the engine if the starter battery fails.2:33 Jeff Cote notes that this setup prevents house loads, such as fish finders, chart plotters, and refrigerators, from draining the starter battery during extended periods of trolling at low RPM.3:06 When engine loads exceed the alternator's output at low speeds, a dedicated house battery ensures the engine remains capable of starting.4:03 Blue Sea Systems manufactures these switches, which feature four connection posts on the back to manage the dual-circuit architecture.2:40
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