On car battery charging.

[johntheo]

Have you monitored the charging rate while driving normally, you can buy a cheap voltage meter that plugs into the cigarette lighter socket. All modern cars with smart alternator charging vary the charging voltage between ~ 12.8v and 14.8/15V on car overrun with accelerator released.

 

[mainline]

Well since it hit full charge last week my girlfriend who predominantly drives it said the stop/start has operated once this week.

Lots of prerequisites for start /stop to function, not just battery condition things such as engine temperature and Air con along with a string of other things usually depending on the make / model.

Obviously none of these are being met in your case, short journeys for some cars are not good at all causing cat / dpf and turbo problems.
Also battery changes on modern cars usually need programming in, again depending on the make / model

 

[westward10]

It is a Fiesta ST3 and owned since new in 2020. Fine through the first summer, one winter and never been the same since but admittedly it only does a short trip each day. Apparently this is none too uncommon for this model but being serviced in a month or so and will throw the problem at them. All the other parts which shut down like touch door opening now fully function but they only need limited power.

 

[mainline]

It is a Fiesta ST3 and owned since new in 2020. Fine through the first summer, one winter and never been the same since but admittedly it only does a short trip each day. Apparently this is none too uncommon for this model but being serviced in a month or so and will throw the problem at them. All the other parts which shut down like touch door opening now fully function but they only need limited power.

I suppose the only way forward is battery test and current consumption after every module that's going to goes to sleep.
Should be looking at around 50ma or so.

 

[DPG]

It is a Fiesta ST3 and owned since new in 2020. Fine through the first summer, one winter and never been the same since but admittedly it only does a short trip each day. Apparently this is none too uncommon for this model but being serviced in a month or so and will throw the problem at them. All the other parts which shut down like touch door opening now fully function but they only need limited power.

Nice car. I like a Fiesta ST.

 

[westward10]

The intention was a Focus RS but I compromised as my girlfriend predominantly drives it but in hindsight the Fiesta was probably the best move, she is country bred and considers the lanes as race tracks she drives at 70+ with no concern whatsoever but put her on a motorway she sweats.

 

[DPG]

The intention was a Focus RS but I compromised as my girlfriend predominantly drives it but in hindsight the Fiesta was probably the best move, she is country bred and considers the lanes as race tracks she drives at 70+ with no concern whatsoever but put her on a motorway she sweats.
View attachment 97464

That is a cracking looking car. Always had a soft spot for fast Ford's