This is a bit long please read all :). It was registered in September 2021. We bought it in January 2022. The car went into deep sleep mode immediately or after not being driven for 24 hours. After lots of fault-checking, Ford replaced the battery under warranty in March 2022. Car was pleased and awake.

The Ford Pass app stopped sending messages until May 2023. The first message I get is car is in deep sleep mode. Autostop start and keyless entry stop working. The car is driven every day and does longer journeys as well. After doing 50 miles the car was back in deep sleep the next day.

We have been checking the battery using a multimeter (I think) every morning and every evening. In the morning, the battery reads 12.31V. In the evening the battery reads 12.5 or 12.6 V. The battery is losing charge overnight and the car is going to sleep. There are no modifications, and nothing is plugged in. The battery charges up when the car is driven. This battery is now 15 months old. Car drives daily between 25 and 50 miles a day but also short journeys.

This week I rang Ford Garage. It went in today for a battery check. They tell me the car battery is fine. I left it there over the weekend and the battery will be checked again on Monday. I still think that there is a battery problem. Ford and the manufacturer disagree. Has anyone else had this issue and what was the outcome?

 

Many thanks

I forgot to add the car loses around 0.2V a night. It has been left at the garage over the weekend and will not be driven for three days so that we can check if it drops 0.2V every night.

This is just the regular phenomenon that at least half of all drivers of new/modern cars encounter. You just need to give the car battery a good charge for at least 12 hours with a Smart battery charger, and to get the batteries state of charge back to at least 80% or better. Your car has done well to manage as long as it has without the battery being 'topped up'. All batteries will loose charge overnight and 0.2V is quite an acceptable amount.

Make sure to charge the battery while it is still fitted and connected to the car. Connect the positive charging lead direct to the battery terminal. Then connect the negative charging lead to the chassis main earth point, do NOT connect it to the battery terminal.

https://www.amazon.co.uk/Maypole-7423A-Battery-Charger-Electronic/dp/B009A83P1E/ref=sr_1_5?crid=347BVXS0ZIFFI&keywords=maypole+battery+charger&qid=1686935687&quartzVehicle=29-10519&replacementKeywords=maypole+battery&sprefix=maypole+%2Caps%2C302&sr=8-5

Just a little side note, does the original poster use Securilert via Ford Pass?

As of June 1st Ford have disabled, allegedly it in the hope of reducing all these “deep sleep” messages.

I'm updating this for anyone with similar battery-related deep sleep issues. The car goes to sleep 24 hours after it is driven. Other signs are problems with the doors unlocking and auto stop-start not working.

My Fiesta passed the battery test on Friday with a SOC of over 80%. The car had been driven to the garage and the battery charged up. The dealer was happy that there was no fault and that the battery was fine. I refused to take the car and asked them to keep it for the weekend. The battery was tested again this morning. Three days after it was last driven. The car went into deep sleep on Saturday. The SOC has dropped to just over 30%.

Ford is apparently aware that the 12V battery used in these cars has problems. My car is going back in for more tests and software checks but they have admitted that it has a fault. Sadly they are planning to fit the car's third new battery. It's only two years old. The battery will be the same type and the same manufacturer. (They jokingly said that they are expecting to see the car in a year - I think it will be less).

The newly named "DoDo" Fiesta is now back at home and wide awake (until tomorrow) as I had to drive it longer distance to make sure that the battery was charged.

 

I had the same problem, I changed the battery for a larger capacity E39 AGM rod, I never had any problems.
But before changing, do a test, in the morning if the car does not start, disconnect the positive terminal of the battery and reconnect, because there is an update for the blocking of the modules, that is, the car has battery but it does not start.