Because I'm not at all practical when it comes to cars I'll be visiting my dealer when I can ... but I'm intrigued to know if this is a common fault with auto-start-stop (and/or am I doing something wrong).

My Titanium Focus is just over 3 years old with about 42,000 miles on the clock.  Over that time the auto-start-stop system has worked impeccably and I have always been content to leave it on except for city driving or when traffic is particularly congested with lots of starts and stops.

I've been away for a week and, as usual the auto-start-stop didn't work for the first 24 hours.  Thereafter it worked fine for a day or two.  Then today I found on stopping at some roadworks when I put the gears into neutral and applied the handbrake the system appeared to work but the moment the rev needle hit zero the car started up again.  And so it has done for the rest of the day, right up to 20 minutes ago!

I cannot see i have access to make any adjustments - is there anything I could or should be doing?  Until I get to the dealer I will be switching the system off using the button on the central console.

Use the site search "Start/Stop" over 250 threads on the subject.

https://www.fordownersclub.com/search/?q=stop start&quick=1&updated_after=any&sortby=relevancy&search_and_or=and&search_in=titles

Really?

7 minutes ago, Linds said:

is there anything I could or should be doing? 

ignore it

Lol my stop start has a tendancy to start working when I pull on the driveway at the end of a journey.

3 minutes ago, Pigeon12 said:

Lol my stop start has a tendancy to start working when I pull on the driveway at the end of a journey.

So it works perfectly, it knows you're home 😀

28 minutes ago, Linds said:

Then today I found on stopping at some roadworks when I put the gears into neutral and applied the handbrake the system appeared to work but the moment the rev needle hit zero the car started up again.

Before I got into the habit of switching the system off as soon as I get in the car, I've had similar with various cars, usually, but not always, when there's high electrical load e.g. air con. The system seems to operate but then decides the battery is too low and starts the engine again.

You don't mention if you have tested the battery voltage? (If it's only around 12.3v (approx 80% SOC) it's borderline as to whether S/S will operate.)

You could just follow Unofix's suggestion.  Or you could try giving the battery a top up charge using a smart charger such as Maypole, C-Tek, or Noco. 

Unless you're experiencing other problems, your dealer will probably come out with some helpful suggestion like "give it a good run" or try and sell you a new battery.

 

 

41 minutes ago, Eric Bloodaxe said:

or try and sell you a new battery.

Oh no !!

Those poor dolphins, not yet another battery added to the tip ? 🤣

SOC table since I've not posted one today 😉

Just don’t use it, terrible idea, which will eventually kill the car. 

3 hours ago, unofix said:

Use the site search "Start/Stop" over 250 threads on the subject.

https://www.fordownersclub.com/search/?q=stop start&quick=1&updated_after=any&sortby=relevancy&search_and_or=and&search_in=titles

... I know little about cars but I do know how to search a Forum.  I just got bored reading threads that did not seem relevant to my specific issue.  I'm sure there will be something somewhere ... tbh I didn't have the patience to find it.  Nevertheless thank you for the link ... 

Thanks for the replies ... I'll leave it to the dealer ... 

If they’re as helpful as the ones in Sussex, they’ll tell you that you aren’t using the car properly 🤣

If you want your S/S to work and not have those annoying low battery messages it’s easy to permanently fit a battery charger cable so you can top it off every few weeks. Me neighbours thought I had an electric car!

You are wasting time and money going to a dealer. Your system is working as designed by Ford. In the interest of claimed emissions, Ford have elected to not allow the battery to charge fully and therefore reduce the load of the alternator. In warm weather, if you drive long distances and don't use much electrical equipment and the battery is relatively new the stop/start may well work. The system will gradually disable high current draw items as the battery State Of Charge (SOC) gradually drops below the pre-set 80% under adverse conditions, such as short journeys, cold weather, battery ageing. Stop/Start is usually the first to be disabled, and annoyingly, in winter, the front screen heater is also disabled. You can either leave it on a smart charger when parked at home or a more permanent solution is to use FORSCAN to raise the SOC from 80% to 90 or 95%. This allows the system to charge the battery to a higher level and will use a very, very, very small amount of extra fuel. So little extra that you will not notice.

7 hours ago, Linds said:

.  I just got bored reading threads that did not seem relevant to my specific issue.  

People ask the question in many different ways but it mostly comes back to the same thing - the "intelligent" charging system in the car is not up to the job as @Paulius55summarises nicely above.

 

Or use forscan to disable it completely, it is a well discussed, unnecessary strain on all the relevant systems, just to make the emissions figures look good for the manufacturers, if you have any mechanical sympathy, you would turn it off every time you drive. 

After a battery replacement in my car, a few weeks and the start stop was had it.

Like others have said it only works when the battery is really good health.

My resting battery voltage is 12.06, what confuses me though is all of my journeys are between 6 and 40 miles without shutting down, I got a new battery during COVID and surprises me how quickly the battery went down to 50% - and now stays there...

Would a home charger get the battery back to a generous level?

Home charger? Surely you mean battery charger?

Linds. You've stated that basically the start stop function has been getting worse over time. Do you have the air con on all the time? This alone will stop the stop start function operating. That's what I've found out this week and been told also by a number of garages. 

Blimey I didn't know that battery state of charge could be altered with FORScan. Good shout Paul 👍

 

1 hour ago, mburdett555 said:

After a battery replacement in my car, a few weeks and the start stop was had it.

Yes, it doesn't take long even with a new car for these things to act up, as I've posted elsewhere recently:

On 8/7/2023 at 8:43 PM, Eric Bloodaxe said:

Small update after now having the car 4 months. Popped out in the car this morning, and being in a hurry forgot to switch off start/stop as is my normal "cockpit check" routine.

Came to the first set of red lights, slipped into neutral, clutch up, the engine kept running and the crossed out A symbol was showing. 

So that didn't take long to find one of the (is it 129?) reasons not to work!😀

 

 

On 8/8/2023 at 2:38 PM, Eric Bloodaxe said:

We jest, but I wonder how many batteries that were perfectly serviceable (perhaps with the occasional charge) have been binned, and what the environmental cost of disposing of the batteries and manufacturing new ones has been.

In similar vein, I wonder what the balance is between energy saved by "intelligent" charging systems in cars, versus the energy used to top batteries up with a charger, because the cars system is not charging sufficiently?

Back to mine. It was showing 12.42v on the multimeter yesterday (or bang on 80% SOC as per our favourite chart). What a surprise!

Today I set off and deliberately didn't bother to switch off start/stop 'cos I knew it wasn't working yesterday. First set of lights - it worked! 

Giving it a charge anyway!

 

On 8/9/2023 at 11:42 AM, Eric Bloodaxe said:

So, not having the ultimate charging machine (Maypole😀) used my C-tek MXS 5. Once connected it went to position 4 which is 80% charged so tied in with the meter reading. Took 6 hours to get to position 7 (fully charged) and now reading 13.2v. 

Looks like this car will be very much as per my previous Mk 8 and need occasional top up charges, as my pattern of use, like many other people's, obviously doesn't suit Ford's algorithms!

 

2 hours ago, mburdett555 said:

After a battery replacement in my car, a few weeks and the start stop was had it.

Like others have said it only works when the battery is really good health.

My resting battery voltage is 12.06, what confuses me though is all of my journeys are between 6 and 40 miles without shutting down, I got a new battery during COVID and surprises me how quickly the battery went down to 50% - and now stays there...

Would a home charger get the battery back to a generous level?

Was the BMS reset correctly?  Is it the right battery?  It should be charging to more than that. 

It's the Mk4's that have minimal charge for super tight emissions regs.  I had a couple of Mk3's, presumably still on the original batteries at 5 years old, and the SS worked perfectly.

The "SS" has of its own accord gone back to working perfectly ... I guess this may have been a minor glitch or just a coincidental reaction to a certain level of battery charge whatever.

So this mechanically unsympathetic driver is happy to carry on killing his car in the cause of ... reducing pollution?

Just a little amazed that a simple little question should stir some really quite deep feelings/reactions.  It's just a car after all is said and done!

I think the strong reactions is more about the number of times this gets asked than the actual question itself. It gets a little tedious for the regulars. 😅