Auto Start/Stop - Pros and Cons

jaybeetoo

InsideInsurance wrote: »

What do you do at traffic lights then, out of curiosity? Engage Park or use the handbrake if you have one? Doesnt stop start work with either of these? I know ROSPA recommends leaving automatics in Drive when stationary at lights etc.

I leave it in drive and put my foot on the brake (sorry driver behind) so the stop/start works.

WTFH

InsideInsurance wrote: »

When the engine goes off the A/C and heater do continue but at a lower level than when the engine was on. Not sure if the climate control is struggling if it will cause the engine to switch back on as the car has a number of additional triggers for it compared to a normal one

On mine if the A/C is struggling and the cabin temp starts to climb then the engine will fire up again.

Ultrasonic

InsideInsurance wrote: »

When the engine goes off the A/C and heater do continue but at a lower level than when the engine was on.

I thought AC compressors were driven by the engine turning, and so would have no option but to stop when the engine is off? Although the part that cools the air would still be cold, and so an electric fan blowing air across it would still have a cooling effect, which is possibly what you were referring to.

chevettedriver

scaredofdebt wrote: »

Thanks guys.

I'll leave it on for now, fuel consumption is around 65 MPG so fairly happy with that.

Thanks.

Wow! I am extremely jealous, as our ageing 406 automatic petrol can only manage 20mpg around town, sometimes less!

I initially thought it was faulty, and had garages looking at it until I found the original spec which confirmed Urban MPG was indeed stated at 17mpg when it was sold!

Who would buy a car nowadays with that spec!

I think you should be OK with your stop/start, it's a heavily tested system, you could always try a week on/off to see the difference.

InsideInsurance

Ultrasonic wrote: »

I thought AC compressors were driven by the engine turning, and so would have no option but to stop when the engine is off? Although the part that cools the air would still be cold, and so an electric fan blowing air across it would still have a cooling effect, which is possibly what you were referring to.

Possibly, I am not an expert on these things. I see on Wikipedia that some cars have an electric motor to drive these things whilst the stop/start have stopped the engine.

No idea if my car has this or not. I know it continues to demist the windscreen but obv not a good sign one way or the other

neilmcl

Ultrasonic wrote: »

I thought AC compressors were driven by the engine turning, and so would have no option but to stop when the engine is off? Although the part that cools the air would still be cold, and so an electric fan blowing air across it would still have a cooling effect, which is possibly what you were referring to.

Not on stop/start systems hence the need for large AGM batteries.

GolfBravo

Not all stop-start systems use a starter motor, eg. Mazda.

chrisw

neilmcl wrote: »

Not on stop/start systems hence the need for large AGM batteries.

No, Ultrasonic is right. The compressor is driven by the engine, and when the engine stops the fan runs at a slower rate to blow the residual cold air. It only expects the car to be stopped for a couple of minutes or so, but any longer than this and the cabin temperature begins to rise above a set level and the engine restarts itself.

marleyboy

I'm in two minds about start\stop. The fiat500 has it installed and I got fed up of drivers telling me my lights were off everytime it stopped, so I disabled it.

However, I now have an S-Max, which also has start\stop. I originally disabled it out of instinct, but over time it grew on me with the S-max, particularly that it starts as soon as I press the clutch and the lights at least stay on when it is activated.

InsideInsurance

chrisw wrote: »

No, Ultrasonic is right. The compressor is driven by the engine, and when the engine stops the fan runs at a slower rate to blow the residual cold air. It only expects the car to be stopped for a couple of minutes or so, but any longer than this and the cabin temperature begins to rise above a set level and the engine restarts itself.

So wikipedia is wrong when it says some vehicles have an electric motor to drive it when the engine is off?