Adrian wrote:
The Natural Philosopher gurgled happily, sounding much like they
were saying:

Not really. One litre of petrol provides 35MJ of energy, about 10kWh.
Even a small car will have a c.50 litre fuel tank, something the size
of an S-class nearer double that.

So that's 0.5-1MWh of energy on board. Wonder how big the battery pack
would have to be to replace that...? Wonder how long it'll take to
recharge...?

You forget that that energy is converted at less than 27% peak
efficiency, propably less than 20% average.: its nearer 95% with battery
electric, and with regenerative braking you get a little free recharge.

In reality 50Kwh will do a couple of hundred miles on a commuter car,
and probably abut 200Kwh is enough for a big saloon

So how come 1.5kWh only gets the Pious two miles at slug-pace? Yes,
that's equivalent to about 60mpg, so it's certainly more efficient than
the internal combustion process, but it's not as big a difference as
you're claiming.


I wont say anything about the Priapus, because its a complete piece of
****, frankly.


And the answer to how big that is, is well under half a tonne for the
smaller one.

...or about half the weight of the rest of the car...


Similar to the power train on an IC car. Remember the motors will not be
large, and there is no need for much in the way of transmission, or
engine or battery cooling. Or exhaust systems, or oil coolers, or the
strong mounting frame needed to tie that lot together.. or the
insulation to keep all that noise and vibration out..or indeed most of
what makes up the weight of a current IC car.



And indeed on longer trips an hour recharge time for driver AND car
every 200 miles is not actually a bad thing!

An hour to recharge 200kWh?

Yup.
Its not dependent on the size of the battery, though you need some
pretty serious charging equipment to do that. But we are talking
multi-million pound motorway service stations here. I don't see any real
problems in running a small substation in to them, and having the odd
440v 120A 3 phase connector littered around the parking lots..or
whatever combination of volts and amps seems most appropriate.