"Brian Gaff" wrote in message
...
I would have also thought it puts a lot of stress on parts from cycling
through, like the starter motor and the actual linkages in the engine
itself.

If you are driving in stop-start traffic, so the engine is stopping and then
having to be restarted every few seconds, it will eventually flatten the
battery because the time that the engine is running is not enough to put
back the charge that restarting has taken out of it. Cars with auto-stop
usually have batteries with larger amp-hour ratings (*) so they can store
more charge to compensate for the increased use of the starter motor.

Usually I find that the engine stops once when I join a queue of traffic at
lights, and then restarts when I'm ready to start moving through the lights.
But in a long queue, it may have to stop and start several times to get me
right through to the head of the queue where I can then drive at a normal
speed.


(*) Just as diesels have a larger Ahr rating battery that petrols because
the higher compression makes it more difficult for the starter to turn the
engine over.