On Tue, 29 Nov 2005 21:51:48 +0100, AJH wrote:

On Tue, 29 Nov 2005 18:48:55 +0000, The Natural Philosopher
wrote:

They got - at an average speed of 50mph - a figure of 217Wh per mile

This is three times the consumption you posted in the other thread.

That means to achieve 500 miles range they would need just 10KWh.

I make it 10 times that.

Oh. Lets go over the figures again.


This on a 200bhp sports car..

I still reckon that to get serious range at sensible power levels you need
around 50KWh.

There is the issue of installed battery capacity being different from
acceptable depth of discharge. When we looked at battery storage for a
remote site the capital charges on the battery were twice the cost of
the generated electricity's fuel portion, which itself was about the
same as grid power.

The battery capacities I am quoting are essentially to the acceptable level
of discharge. Although its not great to go to the absolute limit, lithium
ion batteries ae pretty good up to the last 10% of useable discharge - then
the volts drop rather fast, and you are into areas where one or more cells
in a multi-cell pack may be dameged if you go fiurther. I envisage modular
packs each with sensor on that would warn of this, and possibly take
sections of the pack out of service, rediceing power but allowing a 'carwl
home' mode.


I'm not knocking the concept and I will look at the rest of your post
again but am pushed atm.

Me too.


AJH