Electric blanket current draw

It gets cold in Oz Possum - I won't leave home without an electric blanket.

Mike Harding

Robin, G'Day

60w at 12v = 5amps, or 2 engels flat chat.

600w inverter, whats the draw on that?

Watts = volts x amps

600 = 240 x I

I = 2.5a

If this is correct, then you get a 2.5amp advantage from the inverter, from where? energy doesnt come from nowhere?

or if you use 12v on the inverter wattage it would draw 50amps!

So whats the go on the inverter?

I actually got one, its only 150w but was free with Engel, never used it.

Rgds

Ron

Hi Ron

Nothing wrong with your figures but your reading a bit much into my reply.
I was just saying that a fairly popular size inverter (600w) is adequate for the job, of running the 3 or 4 60 watt blankets mentioned.


Robin Miller

Robin,

maybe this came across wrong,

I was asking whats the advantage of the inverter and if its a 2.5amp less draw how does it achieve this?

I'm not real clued up on inverters except that I imagine they would have a large current draw?

What would the 600w inverter draw from your battery with the 60w load, would it be 0.25amp (240 / 60) or 50amp (600/12)

Guess what I'm saying is do you work out the load on the battery from the inverter, or the load on the inverter from the blanket?

When there are the two ohms law equations, how do you use them together to work out the battery load?

Just curious, and your explanations are always interesting.

Rgds

Ron

Hi Ron

Gotcha now - the inverters are roughly 90% efficent at maximum and a bit less at small loads cause they need maybe 1/2 amp standing current so a 60w load (blanket) would draw about 70w out of the 12v battery or almost 70/12 = 6 amps approx.

Robin Miller

See, even an old dog like you can be edumacated. Down south Dougy, it gets what we call "cold". That's something that makes brass monkeys loose important little bits. About 6 weeks ago we had 3 nights in the Flinders ranges and the morning temps were -8, -9 and -8. An electric blanket would've been a welcome peice of kit.