? DC - AC watts Amps ?

[TimC]

Another silly experiment that I have questions about...

If I am running "an AC appliance" with an inverter from my 12v battery - The appliance uses 17w @ 120v. How many 12v battery watts and/or amps am I using running this appliance for one hour?

[OP827]

Power consumption from the battery would be 17W/0.9=18.9W where 0.9 is an assumed efficiency coefficient of an inverter. 12V battery will be drained at 18.9W/12V=1.6A current or 1.6AH in one hour. Real inverter efficiency and output voltage, and battery voltage numbers may vary.

[bdosborn]

Multiply AC amps times 10 to get ballpark DC amps to the inverter.

Bruce

[TimC]

Power consumption from the battery would be 17W/0.9=18.9W where 0.9 is an assumed efficiency coefficient of an inverter. 12V battery will be drained at 18.9W/12V=1.6A current. Real inverter efficiency and output voltage, and battery voltage numbers may vary.

Thanks, that helps. 1.6a is not as bad as I guessed. In eight hours I would drain the battery ~13aHrs.

I'm going to assume the worst as far as inverter efficiency. It is a twenty+ year old 150w cigarette plug in car inverter. It probably should be recycled as I plugged it into the "appliance", a seedling heat mat, and after an hour the inverter was warmer than the heat mat! Going to look at a modern version with 200 or 300 watts.