"Tim Wescott" wrote in message
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On Mon, 25 Jun 2012 21:33:24 -0700, PrecisionmachinisT wrote:

"Ignoramus6950" wrote in message
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I was thinking about electric cars today.

An internal combustion car, burns fuel inside cylinders and produces
energy according to Carnot cycle. Say, it makes 28% of energy from the
total BTU of fuel that it burns.

Compare it with an electric car. A coal electric power station operates
at efficiency of 33% (Wikipedia).

Then 10% of this is lost in power distribution.

More lost in stepping down line voltage to 220 volts.

Further, more is lost in a battery charger.

Then more is lost in the car battery.

Then more heat is lost in motor windings and power semiconductors.

This is probably by far less efficient than internal combustion an
distribution of gasoline!

And how is it going to reduce CO2 emissions, if more CO2 needs to be
burned as coal than would come from gasoline?



As far as cost per mile traveled, there can be no doubt that fully
electric automobiles are extremely economical to operate, and except
for energy that's lost due to heat and friction, they are 100% efficient
all the way from zero clear up to full rated output.

Nuh uh. Nothing is 100% efficient. If perpetual motion is pie-in-the-
sky, 100% efficiency is the pie plate.

Which is why I mentioned "heat and friction loss"...

--learn to read, pal.


While I haven't seen power budgets, if an electric car manages to take
80% of the energy that came in on the charging plug and turns it into
forward motion, I'd be surprised.


The rest of it "evaporates".....same as with a gasoline vehicle...