Hi everyone,

I hope someone had this issue before and have a proper solution for it. I have a F30, 328i x drive 2015 with the 57000 km so far.
Since 3 weeks ago when sometimes I start the engine, I hear the 2 knocking noise from the driver side behind the cluster or around it. This is not related for when the engine is cold. Sometimes when I drive even 70-80 km and after 30 min again turn on the engine, I hear this knocking noise but sometimes not at all.

I showed my car to the mechanic and after he connected the car to computer through OBD2, he said it is because your battery is weak (showed 10-10.5 v) and this noise is coming from the speaker because of the voltage changing while start the engine. He said if you change the battery this problem will gone.
I tried to mute the radio as I am not able to turn it off completely but still sometimes when I turn on the engine, I hear this weird noise.

Do you have any idea what is the problem? Do you think is it related to the battery and I need to change my battery?