My 2009 Fiesta 1.4 auto Titanium developed charging faults.  Replaced the old battery, which kept going flat, with a new Varta.  Eight days later this was flat.  It was replaced with new battery which went the same way.  Local garage tested the alternator and said it needed replacing which was done with a brand new unit.  Just over a week later the battery was flat again.  Searched for a parasitic drain without success.  Then read on the forum that one of the wires to the alternator (it's a smart alternator) comes under tension and can fracture.  This would tie in with the performance but could do with more detail of which wire and where to locate the fracture point.  The car is having to be jump started in between  recharges which is a real pain at this time of year. Anyone who can assist with advice will be most welcome.

1 hour ago, snodje said:

  Local garage tested the alternator and said it needed replacing which was done with a brand new unit. 

Is the battery warning light not on ?

29 minutes ago, unofix said:

Is the battery warning light not on ?

 

Was that a 'Yes' or a 'No' ????

Hi yes when ignition is first switched on the battery light illuminates.  When the engine starts the battery symbol goes out as expected.  Battery voltage show 12.3 at rest then 13 + from the alternator when engine is running.  This is why I suspect a broken wire which makes and breaks as the engine vibrates because the battery should otherwise be fully charged at around 12.7 or more.  If you have any other ideas/suggestions please advise.  I did wonder if the 41 amp 360 Varta was underside but the autospares shop assured me it was the recommended size.  The previous battery was 44amp 390 which was three years old.

David

1 hour ago, snodje said:

Battery voltage show 12.3 at rest then 13 + from the alternator when engine is running.

The minimum voltage from the alternator with the engine running should be 13.90V

Your battery voltage of 12.30V shows that it is approximately 70% charged.

Disconnecting the Smart Charge connector from the side/back of the alternator should cause the charging voltage to rise to the default of 13.95V

If you have no battery warning light on when the engine is running, then it would suggest that the alternator is in fact meeting the minimum voltage of 13.90V otherwise the warning light would be illuminated.

Does you car have Bluetooth  phone connection ? If yes, then it it quite likely that the Bluetooh module is not shutting down when the ignition is off.