Ask PYS - Should I Lose Power When I Turn My Source Selector Switch?
October 16, 2020 · 3 min · 2K views
What this video covers
A source-selector switch—often called a 1-2-Both switch—should function as a make-before-break device, maintaining a continuous electrical connection when toggled between battery banks.1:11 If a GPS or other electronics experience a power blip during this transition, the switch contacts have likely degraded due to age.1:53 Replacing the switch immediately prevents potential damage to the boat's electrical system.2:02 Specifically, a faulty switch that momentarily disconnects the battery from the alternator while the engine runs can cause a voltage spike, leading to catastrophic alternator failure.2:05 Jeff Cote of Pacific Yacht Systems advises that these switches are inexpensive components that require replacement once they fail to provide a seamless transition between power sources.1:52 Connecting critical navigation equipment to unswitched power remains a best practice, but the primary issue in this scenario is the mechanical failure of the switch itself.
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