Inverter question

Essentially Ron , but its not cut and dried as various models and types have different standing (permanent consumption) and they also have different efficences.

Generally speakiing inverters are designed for best efficencty up near there maximum hence a 150w unit would typically draw less at 100w than a 1000w unit.

Robin, don't run away. I have similar questions which always have intrigued me, while I am laying there late at night with the inverter turned on and not running anything. :)

I have a Sinegex S300 pure sine wave inverter, which I mostly use for the laptop. My 3 step procedure to use the inverter is
1. Disconnect the battery charger. (I figure there is little purpose in using the battery to charge the battery with all the inefficiency losses.)
2. Plug the lead from the inverter into the main 240V input socket on the side of the van. This thus means in theory all 240V pps and appliances are available. In practise the aircon, toaster, electric kettle, hair dryer, microwave etc etc are not used, but we have used a portable fan and one or two small items.)
3. Turn on the Inverter.

The inverter is rated 300W "continuous power output" and 400W "surge rating". I think I know what that means.
Further it states "max efficiency" 89%. Does this mean that for every bit if power drawn, the best one can expect is 89% back. Obviously it could be much less allowing for cable size, length etc.??

Further "no load current draw" is <0.35A. So when I have been having these thoughts in bed the battery is losing .35A each how long?

Boy oh boy am I out of my depth!!. Can you explain what it all means in terms of how we should use our inverters?

Hi Ron173, I plug it into the mains inlet, (and wired it so I could) because I may wish to run the fan and some other stuff while I am playing with photographs on the computer, but I take your point.

I have a 20i Honda like you and run it when I need the aircon, but have found the fan good for most hot nights.

The point I was making was that some nights I would wake up and find it has cooled and I turn the fan off and jump back into bed and think "do I need to reach down and turn off the Inverter? (I have it mounted on the side of my bed) I have never really known what effect having it on or off does. At least now I know that there is a drain if I go back to sleep and leave it on!