Any knowledgable car mechanics for advice

CEON44

I have an Audi A4 (B8) 2.0TDI  143bhp  2009. Theres a problem which has baffled anyone I've had look at it. The battery always seems to be flat. For example if I turned on the radio without the car running after about a minute I would get a message saying battery is weak, please turn on engine or radio will shut down. At the start I was told by 2 or 3 people it was a bad battery. So I invested in a new one but still the problem persists. I say its a problem but to be honest the car always starts first turn, no matter the weather. So it hasnt let me down yet even though its been like that for 4 years but I would like it sorted. Any ideas of what it could be?

ballyblack

For example if I turned on the radio without the car running after about a minute I would get a message saying battery is weak, please turn on engine or radio will shut down.

I drive a Hyundai and I get a similar message. Its just a warning nothing more

BigAl94

I had the same on my Audi and after a few minutes on my Hyundai - don't worry about it.