On the 268s the rotating battery selector switch controls which battery(s) will be used to start the engine and run a few engine/drive related systems. The toggle switch above the rotary switch and just below the circuit breakers controls the "Ships Systems." A few items like the bilge pumps are wired direct to battery power. The bilge pumps would not draw any power unless they were operating. I'm not sure about other systems like the CO detectors. On occasion we have inadvertently bumped the Ships Systems toggle switch to the "OFF" position. The engine keeps running but everything else gets real quiet.
When leaving the boat for a few hours we typically leave the switches on and shut off what electrical appliances we don't need. If you are leaving for the week you might shut the switches off. Keep in mind that shutting them off will kill power to the fridge and everything else. If you have shore power you might leave the Ships Systems switch on so you have a cold beer when you return......
