BMW 3 Series Battery issue

[liamlagooner]

Hi, First time posting and kind of new to car life (had company cars for years)

I have a 3 series 2006 as a spare car and whilst driving it will suddenly flash all warning lights, radio goes dead and then car slowly dies. I disconnect the battery and reconnect and it works again for a few days but now the disconnecting the battery trick does not work and it wont start again.

Changed the battery and it read 11.1 and started the car, few mins later same death happens and the battery voltage goes down to 10.

Is this more than likely a alternator issue? I am extremely close to not bothering with it anymore but i like the car and wondered if a new alternator would save him?

Thanks, Liam

[Xenoous]

Sounds like the alternator to me. Get a garage to take a look for a professional opinion.

[Scrump]

11.1 volts is a flat battery. I am surprised it started the car.
Can you measure the voltage when the car is running?

[E-bmw]

If your alternator isn't charging & the car isn't used much both could be dead.

Take the battery off the car & fully charge it overnight & see what happens then.

[liamlagooner]

Hi, tried a new fully charged battery and the car started but just drank the charge out of the battery until that was not enough to start the car.