2 hours ago, Derek Belli said:

Appears to be a frustrating problem we ford owners have to suffer, I purchased a focus 2019 vignale estate, went back to my local dealer 4 times total of 19 days

fitted new batteries, battery monitor sensors updates, but the problem would not go away, eventually i sold the car assumed i was unlucky and had a rogue car.

I purchased another a 2020 focus estate vignale just 1350 miles, i have the same problem with this one, It went back to ford, Diagnostic said problem with Battery monitor sensor. New sensor fitted, latest update, They did fully charge the battery checked myself 12.69 volts, worked just six times on the way home, the car was then parked overnight, next morning battery check 12.26volts the stop start has has not worked since.

If you check your battery voltage you will find in the morning you will have a low charge, even if you fully charge your battery, (the stop start will work then) the next morning, low battery voltage no stop start, its has if there is a parasitic drain. Very frustrating . I have  turned off my wifi connection, don`t update using wifi anything i can to help the battery but nothing seems to work, have no idea how to help you guys, I don`t think ford have either.

My voltage is at 11.5/6 everyday. I travel 3.5 miles to work each way and let it tick over for 10 mins whilst I get my trainers off and safety shoes on. 

Switch the car off and it settles at 12v 10 hrs later it's back to 11.5/6v... drive home rinse and repeat 4 days a week, sometimes 5. Take it on a bit of run during my days off (50/60mile round trip) and it still says 11.5/6v the following day 🙄

That seems very low even after a charge. What are you using to monitor the voltage? If it's a unit plugged  into the cigar socket have you checked it against a properly calibrated multimeter?

What voltage are you reading whilst the engine is running at normal road speed?

3 hours ago, mjt said:

Tha seems very low even after a charge. What are you using to monitor the voltage? If it's a unit plugged  into the cigar socket have you checked it against a properly calibrated multimeter?

What voltage are you reading whilst the engine is running at normal road speed?

14.8/9v on a cold start up. It drops to 14.5v on a longer run. 

That looks about right. However if it drops to 12V as soon as you turn off and then settles at 11.5V it looks suspiciously like a defect in the battery. It would be interesting to see what happens if you put it on charge overnight.

I imagine some will say that 3.5 miles is barely enough to put back what's taken out to start the engine, especially if you're using headlights and heated screens, but I commuted that distance for many years without experiencing any problems with batteries getting run down. Mind you, those cars had much simpler - and I would claim much more reliable - systems before all this smart charge nonsense was brought in. From experience I have a deep distrust of anything prefixed with the word "smart"

On an average journey with typical use of electrical equipment in the vehicle, radio, lights, heated rear window, heater blower, brake lights, heated seats etc. etc.  not all at the same time of course, it takes at least 5 miles to put back in to the battery what you have taken out. I do agree your battery voltage seems a little low but on top of the fact you say that you travel 3.5 miles each way  twice a day it's little wonder that Start/Stop dosen't activate.

12 hours ago, mjt said:

That looks about right. However if it drops to 12V as soon as you turn off and then settles at 11.5V it looks suspiciously like a defect in the battery. It would be interesting to see what happens if you put it on charge overnight.

I imagine some will say that 3.5 miles is barely enough to put back what's taken out to start the engine, especially if you're using headlights and heated screens, but I commuted that distance for many years without experiencing any problems with batteries getting run down. Mind you, those cars had much simpler - and I would claim much more reliable - systems before all this smart charge nonsense was brought in. From experience I have a deep distrust of anything prefixed with the word "smart"

It doesn't drop straight away. This morning it was the same. 11.6v on start up. 14.8v from cold start when engine is running first thing. Half way to work and it dropped to 14.7v. Left it ticking over whilst I got out and changed footwear. Switched it off and it read 12.8v then dropped to 12.7v and stayed there. Might go out and check on next break ( 2.25pm) and see what its reading. 

This battery is almost a year old. Will have a word with the Brother in law and see if he can check the battery at source if he's not too busy either Monday or Tuesday.

Is it worth buying a battery to get stop/start to work? Mine hasn't worked for two and a half years now. I'm not really surprised as the battery is eight and a half years old. I'm not replacing the battery whilst it will still start the car.

The stop/start in the fiesta seems a lot more reliable than in the focus.

Only thing is that the batteries are pretty expensive. I would want to go down all avenues first 🙂

 

Oddly today the voltage was up slightly to 11.8v upon first start up even though I used the global opening option to get in. It was sat in the sun 😀

En route to the Covid centre about 8 miles away it dropped from 14.8v whilst running to 14.5v. Not seen it that low in ages.

Left it ticking over in the carpark whilst I went to get my jab then drove home. Will see what it says in the morning.

I think a new battery would be the way to go. They are about £120ish and the Start/Stop system will save you about £10 a year in fuel so in about 12 years time you will have broke even - provided of course the new battery lasts 12 years.

The Start/Stop system is surely a conn, even if it saved you £20 a year in fuel it would still take 6 years just to get your money back on the price of a battery. Then of course there is the environmental arguments of saving fuel and less emissions, we just have to ignor the amount of emissions from the factory that make the batteries and forget about the disposing of the old battery in green manner.

 

I think a new battery would be the way to go. They are about £120ish and the Start/Stop system will save you about £10 a year in fuel so in about 12 years time you will have broke even - provided of course the new battery lasts 12 years.

The Start/Stop system is surely a conn, even if it saved you £20 a year in fuel it would still take 6 years just to get your money back on the price of a battery. Then of course there is the environmental arguments of saving fuel and less emissions, we just have to ignor the amount of emissions from the factory that make the batteries and forget about the disposing of the old battery in green manner.

 

The stop/start system is not intended to save fuel, its intended to avoid gassing pedestrians when you are queueing in town.

ah yes! the pedestrians ... of course !!! and what about all the poor souls that have to put up with the massive pollution from the factories that produce the batteries?

and the people who are exposed to the chemicals and toxic waste materials of used batteries ?

and since stop/start is not about saving fuel why is it marketed as a fuel saving technology?

lets not kid ourselves in the real world the difference that stop/start makes to emissions is so tiny that it can't be measured. Any vehicle produces some of its highest emissions seconds after the engine has been started so unless the 'off' period has been more than a few minuets then what was saved by switching off is lost by the engine restarting.

All of this is of course a pointless debate since in only a few years from now engines as we know them will be history along with stop/start.

my focus was in the dealers yesterday,just for a check, i asked them to check my battery as start /stop  has not worked for awhile, was told the battery was just below 80% so s/s would not work, there advice was to get a smart battery charger that reconditions the battery, this would help with s/s and prolong the life of the battery, explaining that the car systems has a constant drain on the battery so it will never be at 100%

so a ctek mxs 5 is on order to see if it helps.

1 hour ago, steve67 said:

my focus was in the dealers yesterday,just for a check, i asked them to check my battery as start /stop  has not worked for awhile, was told the battery was just below 80% so s/s would not work, there advice was to get a smart battery charger that reconditions the battery, this would help with s/s and prolong the life of the battery, explaining that the car systems has a constant drain on the battery so it will never be at 100%

so a ctek mxs 5 is on order to see if it helps.

That's all good and well but why should you have to fork out for something just to do what the car should be doing itself. 

It's not a good solution for those who have either communal park or no off road parking. 

Our car is parked 70m away from our house but in full view so that's not a practical solution at all.

On another note the voltage was up to 12.2v this morning so yesterday's run out in the sun and ticking over for a while seems to have put a bit of life back into it.

Shame the same cannot be said for myself 😆

When you have charged the battery, the battery monitoring system will notice that the battery is more than 80% charged and the alternator will be instructed to apply less charge to the battery until the charge level falls back to 80%. The stop/start will probably work while the battery is more than 80% charged and then stop working again when the smart charge/battery monitoring system gets the charge down to the required level.