My 2007 Focus has developed a problem where "LOW BATTERY" appears on the radio LCD and the radio powers off. It doesn't matter if the car is on or off. If I am driving, the radio will eventually power back anywhere from a minute to a half hour later, then does the same thing over and over again. It seems to be that when I hit the brakes, it tends to do it more. Probably because of the added electrical draw that the brake lights create.
Anyway, I took the car into the garage today and tested it. I started it up with the radio and lights off and the battery was reading 14.4 volts. I then turned the lights, radio, and flashers on and the battery began to slowly drop to 12.3 volts, and this is the point where the radio shut off and the "LOW BATTERY" message displayed again. A few minutes later, with the car running, there was a short audible buzz noise that came from what I think may have been the alternator area and the voltage began to rise to the point where the radio was able to be powered on again.
I checked all of the possibly problematic fuses in both the engine compartment and driver side panel and they all looked fine.
Can anyone help me out on this one?