Turning engine off at traffic lights...

[richie349]

The subject probably says it all really.

When at traffic lights and local knowledge tells you it's going to be a long wait, is it sensible to turn your engine off? I'm talking about a non stop-start vehicle.

I've started doing this I recently but am not sure whether it's beneficial or advisable.

Your thoughts?

[Rick101]

I sometimes turn off if I'm stuck on the motorway and I'm sat more than a few minutes.

I can't imagine you would be sat at lights all that long to require turning off. I think any benefits would be negligible.

[richie349]

I only do it if I arrive at lights just as they change to red, and I know they have a long cycle.

I wonder about the real benefits of stop-start technology in that case. Stopping for even a few seconds at a time must put a huge strain on the starter motor, etc.

[WhoseGeneration]

The subject probably says it all really.

When at traffic lights and local knowledge tells you it's going to be a long wait, is it sensible to turn your engine off? I'm talking about a non stop-start vehicle.

I've started doing this I recently but am not sure whether it's beneficial or advisable.

Your thoughts?

Bit debatable but remember, stop start vechicles have electrical components designed to accomodate this and provide a reasonable service life.
Considering this, I'd say forget it.

[TheInsanity1234]

I'd say forget it.

Our Yeti has start-stop technology, but we haven't noticed a massive difference in the number of miles we get out of a tank, so there's no real benefit.

It's okay on our car, because the electrical components (battery, starter motor) have been beefed up to accommodate the increased use, but on a normal car, you'd probably wear out the starter motor and thus completely negate any benefits of saving maybe £1 a week in fuel?

[125isfine.]

A modern engine, Petrol or Diesel uses the equivalent of about 20 seconds worth of idling fuel to start.
So if you're stopped for more than 20 seconds then it might be worth switching off.
I had a Smart car with start /stop on it, and it was the first thing I disabled when starting my journey, I hated it.
Every mini roundabout when you have to stop momentarily it would stop then start. Traffic lights whereby you crawl up to them hoping they would change you would stop, then wait 2 seconds before they go to green.
maneuvering , nightmare. Got stuck in a mighty motorway jam inching forward every 30 seconds or so and the battery was discharged after 15 stop starts, light came on, system disabled for about half an hour while the battery recharged.
Stopping in winter, heater went cold within seconds, summer, aircon stopped working. Utter waste of time.
All this with a so called beefed up system, so I certainly wouldn't switch off with a normal car.

[TheInsanity1234]

I had a Smart car with start /stop on it...
[/bemoaning Smart's SS]

It's perfectly okay in our car, as the engine won't cut out unless very stringent criteria are fulfilled.
I quote from the handbook:

The gearshift lever is in Neutral.
The clutch pedal is not pressed!
The driver has fastened the seat belt.
The driver's door is closed.
The bonnet is closed.
The vehicle is at a standstill.
The factory-fitted towing device is not electrically connected to a trailer.
The engine has reached its operating temperature.
The charge state of the vehicle battery is sufficient.
The stationary vehicle is not on a steep slope or a steep downhill section.
The engine speed is less than 1200 RPM.
The temperature of the vehicle battery is not too low or too high.
The pressure in the brake system is sufficient.
The difference between the outdoor- and the set temperature in the interior is not too great.
The vehicle speed since the last time the engine was switched off was greater than 3 km/h. meaning if you're crawling forwards in start-stop traffic, then it won't switch off every time, as well as low speed manoeuvres in a car park.
No cleaning of the diesel particle filter takes place
The front wheels are not turned excessively (the steering angle is less than 3/4 of a steering wheel revolution).

How old was your Smart, anyhoo? Perhaps the system in your car was rather dated, as I know the early ones were a bit useless

[trashbat]

Look up starter motor replacement for your (any) car and you'll see few failures. Battery problems, on the other hand, are prevalent, and it's easy to outpace its charging with a bunch of starts - be it frequent short trips, or something resembling stop/start. You can reduce that by uprating the battery; on an older car, this is as simple as buying a new battery since the standard ones have improved anyway.

Me, I only turn off the ignition when I know with a high degree of confidence that I'm going to be stopped for at least 30 seconds, like in traffic controlled roadworks. Restarting on a non-SS car is slower, so can find yourself setting off late, and you probably don't go through TI1234's checklist either, which would be the right way to do it.

[christopherwk]

Battery problems, on the other hand, are prevalent, and it's easy to outpace its charging with a bunch of starts

My car has a separate battery for the stop-start function. It's in the boot, and a lot smaller than the normal battery, similar to a motorcycle battery.

[Silk]

Battery problems, on the other hand, are prevalent, and it's easy to outpace its charging with a bunch of starts

My car has a separate battery for the stop-start function. It's in the boot, and a lot smaller than the normal battery, similar to a motorcycle battery.

Are you sure it's not the other way around? In other words, the battery in the boot is simply a backup to maintain all the background functions in the event of failure of the main battery. It could also be there as a buffer to prevent things such as the radio going off and the lights dimming when the engine is being restarted.

My car has stop-start and, as far as I can see, only one battery. The main difference is, when the engine restarts the radio stays on and the lights only dim a little.

[trashbat]

It could also be there as a buffer to prevent things such as the radio going off and the lights dimming when the engine is being restarted.

This, I think. For example, on the Jaguar XF:

The Intelligent Stop/Start system is able to restart smoothly in less time than it takes for the driver's foot to release the brake pedal and depress the accelerator. It does so by utilising a Twin Solenoid Starter (TSS) mechanism that features its own secondary battery to ensure that in-car systems requiring power are not affected.

[TheInsanity1234]

The SS system on our Yeti just has a beefed up starter motor and battery, but we haven't noticed any issues with the stop-start. The lights don't flicker on restart, there are no issues or anything

[Mike H]

I have to say that I can't abide stop-start, nor any other technology that thinks it knows better how to control the car than I do! I always disable the stop-start when driving OH's car, as does she. All this park-assist, lane-change assist and adaptive cruise control etc etc does my head in - and we wonder why driving standards are deteriorating yet further - everyone is relying on the car to do the driving for them! God help us if the Google car ever becomes a serious contender for road space.

My new car will be programmed with 'comfort' indicators, or some such fancy marketing name. I don't want the car to indicate three times if I just touch the stalk. I want to determine the number of flashes myself depending on the circumstances at that moment. I've managed to get it disabled on the last two cars, but the new one (from the same group) elicited an 'Oooh, I'll need to see if that can be done, and even if it's possible, I'm not sure **** will allow us to do it'. What the hell is that all about?

Sorry for the slightly off-topic rant, but to the OP's question, no I generally wouldn't bother at a set of lights.

Now, level crossings, that's a whole different prospect.......

[TheInsanity1234]

My new car will be programmed with 'comfort' indicators, or some such fancy marketing name. I don't want the car to indicate three times if I just touch the stalk. I want to determine the number of flashes myself depending on the circumstances at that moment.

*My italics*
I highlight that, because you'll find that if you hold the stalk in place for the duration of one flash, the indicators will not flash 3 times.

My parents' Yeti and Galaxy both have this (Though the Yeti is the only one you can actually deactivate it yourself inside the car, the Galaxy would require a computer to be plugged into the car's computer).

For them, they complain about it, because they find it to be a bit hit and miss, and my sister claims she is completely unable to activate it.

Through my observations of them, I found that the reason why they were occasionally unable to activate the 3 flashes, it was because they weren't "touching" the stalks, they were holding the stalks down, but the duration would often vary to just under the cut off point for 3 flash activation, and just after.

So, I'd suggest to you to just make it a habit to just hold the indicator stalk for the duration of one flash, minimum, if you're in a situation where you don't want 3 flashes.
Play about with the duration lengths and see if you can pin-point where the cut off point is, just so you know how long you need to hold it for.

[tioaboa]

On the stop/Start subject my Mini is pretty good, you have to be in neutral with your foot off the clutch for it to operate. So at a busy set of lights which may change rapidly I'll be out of gear but probably leave the clutch down to avoid it shutting off. I'm Not convinced it saves any fuel tbh.

Also , My mini has stupid indicators that return to centre rather than stay up or down while indicating

Ian