Voltage Inverter

[alan30]

How does a inverter convert 12v DC to 220v AC? Some inverters are capable of handling up to 2000W equipment needs which at 220v is a current of some 9A. Most cigarette lighter circuits in a car have a 3-5A fuse. So how do the numbers work out?

[Space]

if your cigarette lighter has such fuse, then you won't ever get more than 60W out of it.

[qapmoc]

If you want more power you have to connect the invertor directly to the battery terminals with large heavy duty crocodile clips and at 2kW the battery won't last very long.

[mibn2cweus]

P = I x E : Power in watts equals current times voltage.
At a lower voltage more current must flow to do the same work. At 12v the current required for 2000w is 167amps!

[PhilLew]

I have a 3kw inverter in my works van, it powers most thing very well (doesn't like the Arc Welder) but It's hard wired in to the battery with VERY heavy cables and I never use it with out the engine running.

Extremely useful piece of kit :)

[alan30]

Many thanks to all. I only need one to power a laptop as a cigarette lighter lead does not seem to be available so an inverter that works of the cigarette lighter will be OK. I was just intrigued by how the bigger ones work and qapmoc and PhilLew have answered that.

[BillyNoMates]

You should easily find an adapter to power a laptop from a car cigarette lighter socket.

It seems a little OTT to be thinking on an inverter just for this.

Most laptops run on around 18v DC. There are plenty of adapters available to up the 12V to 18v. Some examples here but ensure you get the polarity correct before attaching ;

http://www.maplin.co.uk/search.aspx?MenuNo=791 &MenuName=Notebook%20Adaptors&FromMenu=y&crite ria=Notebook%20Adaptors&doy=1m7&worldid=4