[LINK] Electric vehicles and generation

rchirgwin at ozemail.com.au rchirgwin at ozemail.com.au
Sun Jul 23 14:03:37 AEST 2006

Karl, Tony

Yes, I agree to pretty much everything you both said.

In discussing the "energy budget" of a vehicle, what I have in mind is 
to say "what's the best you could get out of an all-electric car, and is 
that enough to replace the internal combustion engine?" - because we're 
going to need to come up with the replacement at some point.

The absolute - if we're close to maximum battery capacity and motor 
efficiency - is the simple weight-power-distance-elevation calculation. 
So: can the car be light enough to use little enough electricity to be 
practical, cheap, cover long distances, and be rechargeable from an 
accessible source?


Karl Auer wrote:

>>The limit is ultimately how far a body X kg can travel using Y kW of 
>>power, how much you can carry in the batteries, and electricity 
>>distribution practicalities (how many houses can be fitted with 70-amp 
>It runs deeper than that.The real question in all this (apart from the
>question of why we need to use energy travelling) is the *kind* of
>energy we use. Fossil fuels are finite and they pollute (even the
>so-called "bio" alternatives, although renewable, still burn into CO2
>Electricity does that too, if it is generated via burning something, but
>it doesn't have to. Electricity can come from many other sources -
>solar, wind, tide, nuclear etc, and these have far smaller "footprints".
>Hybrid cars reduce fuel usage chiefly by using the energy more
>carefully. An electric car with a small onboard petrol generator, for
>example, doesn't burn lots of fuel starting or accelerating. Because
>speed can be controlled electrically rather than mechanically, you save
>on gearboxes, clutches etc, all of which waste energy. Brakes can
>recover some energy, or at least stop using it when slowing rather than
>accelerating. WAY less energy goes into heating up (and then having to
>cool) the motor. Although the batteries are heavy, you don't have an
>engine block, and many components that add weight to a normal car can be
>much lighter (drive train) or omitted entirely (like motor cooling,
>gearbox etc).
>So the equation is more complicated than just kilowatt hours.
>Regards, K.

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