In article , The Natural Philosopher wrote:
Dave Plowman wrote:

If you're going to build underground car parks for all city cars that
haven't their own off road parking, wouldn't it make much more sense to
spend the money on extending the tube network and making it cheap/free?
An electric car is only suitable for city use and will do nothing for
congestion.

That is simply not so.

With 300 mile range and potentially one hour fast charge from flat, it
would be ideal for rural use and commuting.

Yes,indeed, it would. It is, I agree, a more realistic target than
breeding flying pigs.

2) The petrol used in 300 miles by a typical modern car contains
about 1 GJoule. If we assume a factor of two higher efficiency, then
charging in an hour needs 140 KW. A standard domestic power circuit
is rated at 7 KW. You have a factor of 20 to make up.

Dammit, a CYCLIST will expend some 20 MJoules in 300 miles. Recharging
that in an hour needs 6 KW! There is NO WAY that you will design a car
to be as efficient as a cyclist, despite the motor lobby propaganda.

2) Despite claims, such devices would NOT help with congestion to
a detectable degree.

You CAN fully charge a lithium car in about an hour, but you need
specailsed charging facilities to do it safely.

You need specialised facilities to charge the damn things at all, at
any rate. The necessity for fancy protection mechanisms is one of the
reasons that they are expensive.



Please could you take this stuff to a newsgroup (a) where people are
knowledgable about this sort of thing and (b) where it is on group?


Regards,
Nick Maclaren.