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Re: 12 volt adapter for macbook pro?

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<cmnews-A078BB.22375809032011@c-61-68-245-199.per.connect.net.au>,
Clark Martin <cmnews@sonic.net> wrote:

> > > You can easily pull 200W from a car cigarette lighter outlet, you just 
> > > need a larger inverter.
> > 
> > 200 watts would be just under 15 amps (ignoring any losses in the
> > inverter). good luck on not blowing a fuse. a car's cigarette lighter
> > is *not* designed for that.
> 
> Uh, yeah it is.
>
> The smallest fuse I've ever seen on a cigarette lighter is 20 A and a 
> few times it's been 30A.  The actual cigarette lighter is going to draw 
> a boat load of power to heat up that hot that fast.

i just checked my car and it has 15a fuse for the cigarette lighter,
which means 200w is the limit if it was an perfect conversion (which it
isn't) and if nothing else is on that circuit (depends on the car).

150w is more realistic, and even that's pushing it. one spike and it
can blow. some inverters even have a built-in fan to dissipate the
heat, so there's definitely quite a bit of loss.

the actual cigarette lighter plug (for lighting cigarettes) does not
draw much power at all. it has a very high resistance and it doesn't
heat up all that fast.

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Re: 12 volt adapter for macbook pro? Clark Martin <cmnews@sonic.net> - 2011-03-09 22:37 -0800
  Re: 12 volt adapter for macbook pro? nospam <nospam@nospam.invalid> - 2011-03-10 16:35 -0800

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