HELP! Engine won't start

Arunmor

https://forums.moneysavingexpert.com/discussion/comment/82173320#Comment_82173320

I really couldn't give a monkeys what you think. It works for me and the savings would be minimal. I don't do very much stop start driving anyway. So luddite I am in your southern centric view

Mildly_Miffed

https://forums.moneysavingexpert.com/discussion/comment/82173510#Comment_82173510

If you rarely use it, then what's the issue with it being on? But thanks for proving my point so eloquently.

"Southern-centric"? Don't they have urban traffic in t'north, then? (BTW, I don't live in the south.)

Nobbie1967

https://forums.moneysavingexpert.com/discussion/comment/82173593#Comment_82173593

The biggest issue with it is making the car’s response unpredictable at junctions. You press the accelerator go to pull out just as it has turned off, so it then turns on after a delay, but you may then be unsure about pulling out, but off you go. In a manual it’s just generally annoying, but in an auto it is a safety issue IMHO.

Skiddaw1

We're Up North (for what it is worth 😊) and we have a stop/start (Ford Fiesta). We switch it off in order to save the battery if we're in a big queue but otherwise it's a really useful in my opinion.

oldernonethewiser

https://forums.moneysavingexpert.com/discussion/comment/82173510#Comment_82173510

Presumably then no one needs to give a monkeys about your opinions either. The joys of a public forum 😃

I used to have a stop start function on one of my cars, can't ever recall switching it off.

Perhaps there are geographical differences in the daily use but another non-southern centric person here.

molerat

https://forums.moneysavingexpert.com/discussion/comment/82173320#Comment_82173320

EFB are also used on stop start. Fuel savings on an individual basis are probably minimal but as part of the big picture it probably saves a fair amount of emissions. On my third car with it now and the number of "problems at junctions" can be counted on one hand. The only time I turn it off is when I am doing a map update. One thing that gets me is the number of people that admit to sitting on the brake and clutch at traffic lights and junctions to prevent it engaging.

chuffinnora

https://forums.moneysavingexpert.com/discussion/comment/82171955#Comment_82171955

Yeah I had the same scenario. Had a Ford Focus Vignale for about 5 years. Stop/Start worked for maybe a few months when I first had it. Battery died about 6 months before I sold it. Got the recommended replacement battery and hey ho Stop/Start suddenely worked perfectly. Previously I had thought maybe it was because I had AC and other stuff permanently on when driving but I noticed the new battery had a little higher energy capacity than the one I took out.

Veloflyer

Conservation of energy law dictates energy cannot be created or destroyed. It can only be transformed from one form to another. Nothing (e.g. fuel or possibly even emissions) is "saved" by an ICE vehicle stop/start system as the need to supply the (larger) battery required to power the more numerous high current drain of the starter is cancelled out by the need for the engine to work a little harder to charge the battery than it would otherwise - unless there are other means of charging the battery which normally there is not.

For sure you don't notice the engine working harder than it would otherwise, but it does nevertheless as that battery electrical/chemical energy has to come from somewhere, and ultimately - other things being equal - it may well incur a greater fuel consumption and therefore perhaps even greater overall emissions as a result.

For me it's a bit of a gimmick based on some very dodgy science.

Alderbank

Conservation of energy law dictates energy cannot be created or destroyed. It can only be transformed from one form to another. Nothing (e.g. fuel or possibly even emissions) is "saved" by an ICE vehicle stop/start system as the need to supply the (larger) battery required to power the more numerous high current drain of the starter is cancelled out by the need for the engine to work a little harder to charge the battery than it would otherwise - unless there are other means of charging the battery which normally there is not.

For sure you don't notice the engine working harder than it would otherwise, but it does nevertheless as that battery electrical/chemical energy has to come from somewhere, and ultimately - other things being equal - it may well incur a greater fuel consumption and therefore perhaps even greater overall emissions as a result.

For me it's a bit of a gimmick based on some very dodgy science.

I agree there's a lot of very dodgy science about. You don't need to look further than this thread. For me, any science which doesn't contain a single number and uses words like 'perhaps' and maybe' is very dodgy.

This is an interesting topic and SAE International (better known as the Society of Automobile Engineers), who know about these things, have carried out controlled tests to produce data.

They found that more than seven seconds of idling uses more fuel than start/stop. This is surprisingly low and is because the system only operates when the engine is fully warmed up so just needs a tiny flick of the starter to fire.

They also found that under simulated real-world driving on a test track that the fuel saved is between 7% and 26%, depending on how busy the traffic is. These figures, supported by other trials, also surprised me.

https://www.sae.org/papers/auto-stop-start-fuel-consumption-benefits-2023-01-0346

Do you have any numbers to support your 'dodgy science'?

MattMattMattUK

https://forums.moneysavingexpert.com/discussion/comment/82173954#Comment_82173954

Your post demonstrates a complete misunderstanding of the laws of thermodynamics in application not just being able to recite the base principles.