This is a pretty light inverter. Using the rule p =i*e (power = voltage * current), the 700W / 120 VAC = 5.3 Amps. Depending on what you plug in, you may trip the overload protection.
1. I assume that this is a cigarette lighter setup, that your boat has a master OFF switch, and that the cigarette lighter plug is wired through the switch panel and not direct connected to the battery (dear God I hope so). If so, then simply switching the master power to OFF will keep your battery from draining.
2. I would keep it off or unplug it (if there is no power switch) due to the surge when starting.
3. In general, on the boat I leave electronics off unless I need them. We leave our inverter off until we use it, which is rarely. Of note is that we originally purchased our inverter to power the laptop, but the power loss from an inverter is about 0.5A. So I bought a DC laptop charger and draw 25% less power while the laptop is plugged in. This matters a lot when operating all day and all night without charging the boat's batteries. Invest $20 in a DC laptop charger.
Don't apologize for asking questions. When we question common assumptions, we find how little we really know.
Sabre 38 "Victoria"
Last edited by Sabreman; 02-04-2011 at 05:41 PM.