BMW repeats “voltage too low” and cuts off. How do I fix the voltage problem?

What is your question?

Car idles off and says voltage low. Won’t stay started without pressing gas pedal. Voltage too low keeps repeating. It starts fine but will not stay running without gas being pressed at idle. Constantly restarting in stop and go traffic as a result of the voltage too low problem. Battery seems fine all else works but whatever makes the voltage too low is preventing the car from running at idle for long.

What makes this problem better or worse?

Stop and go traffic makes the car turn off every few feet

How long has your 2003 BMW 325i had this problem?

Weeks