If you have low voltage, sometimes a pressure regulator will not function. But if the boat is at the dock on a charger -- unless you had a bad connection or a wire that had deteriorated, that's less likely.

The newer variable rpm/frequency pumps aren't perfect either. They use a bit more power, they're always on when you take an water. With an accumulator, you can take a "shot" of water to rinse your hands or dilute your scotch without the pump going on. ;^)))