2000 Ford Crown Victoria, 133K miles (new engine at 96K)
When I'm accelerating onto the highway or some other time when I need to lay into it, the battery light will briefly come on for perhaps a second at high RPMs; it goes out immediately upon shifting to the next gear. There is a voltage gauge in the cluster, and I do notice a very slight drop in the gauge when the light comes on...though it's not getting anywhere near the red area. I should mention that, when the car upshifts to the next gear and the light goes out, at that moment I sometimes hear a brief chirp from the belt.
The battery connections are clean and tight; battery voltage tests normal when the engine is off (~12.5 volts), and the charging voltage tests normal at idle (~14-14.5 volts). The serpentine belt is in good shape and feels tight. Anyone have an idea what might be happening?