Got Auto stop/start on the BMW. It's my third BMW with it, all have been 2.0 diesels. SWMBO's Z4 2.0 petrol has it as well.

Come to halt in traffic / at lights. Move gear lever to neutral. Lift foot off clutch. If the car meets parameters (outside temp over 3 C, battery has enough charge, etc) engine stops. As soon as you press the clutch pedal, engine re-starts.

on an automatic then it works even more seamlessly - you don't need to do anything at all. Just come to a halt for a few seconds and the engine will cut out. As soon as you press the throttle the engine restarts and engages the gearbox.

I struggle to see what is so stressful about it to some people.

I struggle to see what is so stressful about it to some people.

Turbos don't like being stopped quickly - I guess those who replace cars every 3 years have no interest in longevity.

If you're in stop/start traffic, then the turbo won't be that hot. So that problem doesn't exist.

Even if you've just come off a motorway after 150 miles at 75-80mph and are parking up, with the slowing down on the sliproad and getting to a parking place it's going to take a minute at least, during which time the turbo is being cooled down.

HJ himself says that "it is wise to idle for 30 seconds or so when the turbo is red hot". I'd happily argue that a minute (plus) of slowing down and parking up will accomplish that, in full.

So you're really left with cases where you're blatting down the motorway at full cruising speed with the turbo red-hot, and then come off the motorway straight into standing traffic. No warning, nothing at all, hard on the brakes from 75 to 0, and then sit there.

Can't think of many times that's happened to me in the last 28 years of driving.

Those who don't mind stop/start systems may change their view if they need a new starter motor outside warranty, the cost is much higher than for a normal starter. The batteries aren't cheap either .

Considering auto stop/start systems have been out for quite a few years (BMW, for example, introduced them on a lot of cars in 2007/2008, I seem to recall), you'd expect the HJ problem pages and these forums to be full of starter motor and battery problems if there were weaknesses in the systems.

Especially considering that modern cars have far more electronic demands than even a decade ago

And yet we aren't seeing constant posts of that sort, weekly gripes on the 'Ask HJ' section and Q + A.

So, there is a large lack of evidence of such problems, where you would expect to see such evidence - IF those problems were as widespread as some people seem to fear they should be.

AGM battery replacement has become a service item on many cars with SS - it can be eye-wateringly expensive as the ECU's have to be matched to the battery capacity/charge.

No problems to report if you change it on schedule - just £££££

OK, here's a challenge for you then. Show me one car on which the battery is a 'service item' to be changed on a schedule.

Erm ...

VW's website states that the battery needs to be checked 'at every service', and they state that they 'may need to change your battery if it's not holding a charge, or look at why it's not charging when you drive'.

Similar on Skoda.

Audi's site says that they inspect battery condition, and colour it green, amber or red on the report.

SEAT similar.

Doesn't say anything, anywhere, about it being a routine replacement at 5 years old.

Why so much antipathy to stop-start systems?

The doom-sayers who predict dire consequences seem to be basing their prejudices on a hypothetical increased risk of mechanical failure & associated costs (rather like HJ's ongoing campaign against "normal" v "super" fuels, which rather surprisingly, if valid, doesn't seem to have the backing of any major motor manufacturers!).

But this is missing the point that even if there is an increase in cost at some stage down the line the reason for fitting - and leaving activated - S/S is not to save costs but to reduce pollution levels which otherwise will ultimately damage the lives and welfare of our children & grandchildren. As I wrote a couple of days ago, I'm not a "Green" voter - but hope that I have a modicum of social responsibility for the welfare of others, so I leave my S/S button alone in the default position.

Edited by Theophilus on 02/12/2017 at 14:20

My Astra 1.0T has stop start and I generally leave it to do its' own thing unless the weather is hot and I want the air con to continue running, or cold and I want heat.

The engine cuts out at the earliest opportunity. In warm weather it will stop (from a cold start) at the junction 1/2 mile from home. The only time I disable, other than as previously mentioned, is in heavy stop start traffic (which I rarely encounter) as whilst the stop is not noticable, the restart is and it can get on my nerves after a while due to the vibration of a three cylinder starting. Once running, the engine can't be felt or heard.

As for the doom merchants here, maybe S/S technology is another EPB timebomb but then again, probably just the same dire predictions as heard when central locking and electric windows became common place some decades ago.

BTW. A battery for mine is around £160. Non S/S around £75. Or put another way, more than covered by the annual VED saving (pre 2017 changes).

The Mazda stop-start system (helpfully called "i-stop"), fitted to many models, uses a large capacitor, not the main battery. I gather this is specific to Mazda.

When this is nearly drained (it will last for about one minute) the car will automatically re-start.

I woudn't therefore expect the main battery to have a shorter life than normal.

Indeed-bring back starting handles, they were brilliant at keeping you on the go!

Indeed-bring back starting handles, they were brilliant at keeping you on the go!

You need to be fit to start a diesel by the handle ....

Not so a Lister donkey engine, built in starting handle, valve lifter lever on the head, whizz it round by hand with no compression let the valve lifter go, and away she goes, waking the dead..:-)