On Sep 24, 5:19*pm, The Natural Philosopher
wrote:
harry wrote:
On Sep 24, 10:49 am, "Dave Plowman (News)"
wrote:
In article
,
* *harry wrote:

Volkswagen have been experimenting with *thermpiles in the exhaust to
make electricity and thus eliminating the alternator.
Crikey. An alternator is actually a very efficient device. Sounds like
they're clutching at straws.

An automotive alternator is very inefficient. *And not having it
removes a parasitic load from the IC engine.

Its very efficient. Probably 80% or better.

Wrong as usual TurNiP.

http://en.wikipedia.org/wiki/Alterna...ve_alternators

Efficiency of automotive alternators is limited by fan cooling loss,
bearing loss, iron loss, copper loss, and the voltage drop in the
diode bridges. At partial load efficiency is between 50-62% depending
on the size of alternator and varies with alternator speed.[8] This is
similar to very small high-performance permanent magnet alternators,
such as those used for bicycle lighting systems, which achieve an
efficiency around 60%.