Z4 2006

2006 z4
Hi guys, looking for help on a warning indicator battery light is on when car is started but then will go out after a few minutes.
Manual says alternator not charging . Battery not charging. However why would light go out then?.
Please help.

Belt loose?

Check your battery voltage before startup. Maybe your battery is weak.

Sounds like a weak battery to me.

I think a loose/defective belt is the most likely too. As the engine warms up and expands (slightly tightening the belt) and the alternator warms up and runs freerer, this may well produce enough output that the idiot light goes out. Second guess is the regulator isnt delivering the juice in the specified amounts. Good luck.

Hi!
If you have a volt/ohm meter you can check the voltage at the battery when the car is running. The alternator (voltage regulator) should be putting out about 14.3 volts. If you check the battery voltage with the car not running even a weak battery could show close to 12 volts because there is no draw on it. Like already suggested it could be a loose belt on the alternator, or a weak battery. You can get the battery checked at a auto parts store like Autozone. They can put a load on it and tell you if it's OK.

Good luck