Ford Focus MK4 Battery

[Admanirv123]

Hi, my start/stop generally worked but not all the time. Car is 2019 covered 66k.

I had a ecu bench flash remap by a company, and they fixed an issue so flashed it again all is well. A few days before I did a service on the car or fuel/oil/air filter etc. I had it switched off for at least an but but had to remove the battery hence disconnect the battery connection's to both terminals and wondering if I messed something up I did not do anything with forscan.
As now stop start doesn't work I did a 90 mile motorway run (1.5 hours) before taking these values the night before so must have had enough time to charge?! These are values without car running.

Wondering what steps I should do if I am to reset values etc? Or put external charger on it? It's an agm battery right?.

[Donny]

Your battery is now 4 years old, it will not hold its charge like a new one will.

A 1.5 hour run may only add about 6 or 7 % to the state of charge, best to use an external charger and charge it overnight with the negative cable on the chassis so that the battery monitoring sensor knows how much charge is going to the battery, otherwise it may take several hours before the correct state of charge is registered. The SOC needs to be above 68% for start/stop to work.

The original battery should be a EFB type on these cars, not AGM.

[Admanirv123]

Ah Thank you for the info. Do you mean an additional cable goes from negative pole to a point under the bonnet and I should attach the charger there and not straight to the negative pole on the battery and lastly charger positive directly to positive pole on battery?

Thanks

[Admanirv123]

Connected my charger and after 15 mins it's saying its fully charged?. Soc hasn't increased. Its a smart battery charger I used to batteries lasting 8-10 years so I not sure if I should think about replacing the battery?

[Donny]

Ah Thank you for the info. Do you mean an additional cable goes from negative pole to a point under the bonnet and I should attach the charger there and not straight to the negative pole on the battery and lastly charger positive directly to positive pole on battery?

It is best to attach the charger there so that the battery monitoring sensor can monitor the amount of current being taken in by the battery when charging.

If the charger is only charging for 15 minutes then either the battery is fully charged or it needs replaced because it can't take a full charge.

Check the voltage after the car has rested for at least 1/2 an hour and it has not been woken up by opening a door or anything else. If the battery is fully charged then the voltage will be 12.6 to 12.7. If it is only about 12.4 then it is only about half charged.