IMM wrote:

"Rod Hewitt" wrote in message
.. .

"IMM" wrote in
:


How about heating the car in winter? This would be a traditional
electric element, which consumes a lot of power from batteries. The
car would probably need a layer of insulation to keep heat in and heat
out in summer. Do the batteries produce enough heat to heat the cars
cabin?

Last I heard, it sounded as if 'they' were going to add a small petrol
burner to provide heating. Apparently this was the most efficient/sensible
option, at least in the early days of such vehicles.

Perhaps we will get SEDBUK ratings on them as well as mpg equivalents?


A car has no insulation, as they produce so much waste heat the engines can
provide enough even in the coldest conditions. Adding insulation, bonded to
the cars sheet metal around the cabin, would improve matters. The drive
motors and batteries produce heat, so this must be available for use.



Yes. Cars ARE in fact insulated very well. You only need to take a ride
in e.g. my old series III landrover woith nowt but a sheet of aluminium
between you and the elements to see how MUCH insulation a modern car has
by comparison.

Most cars have something like 1/4" of fibre and carpet on teh floors,
the rear seats line that part of the car, and the doors usually have a
2-4" aiorgap in them. Dreaughts are of necssity totally absent by and
large, and roofs are normally lined with headlining and again about 1/4"
of insulation. some cars even have double glazed windows.

Even with a U value of about 5 - equivalent to a totally single glazed
car, and a square meterage area of - what - 16 sq meters of cabin, that
is 80W per degree C differential, so AT WORST for -5 outside and 25C
inside, it only needs 2.4Kw to heat it. In practice that is a fairly
ludicrous U vcale, becaseu teh glass is thicker than window glass, and
most of the cabin is well insulated.

Lets face it, a lining of 15mm celotex is not going to cost very much.
And there is going to be a wedge of batteries and electronics under the
floor kicking out a hundred watts. Getting heat from the motors - if
thse are ouboard on the wheels - is not so easy, but even there, if
wound with pipe istead of solid wire, the heat could be removed bu
circulatng coolant through them..



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