So do these alternator gauges in our instrument panel actually work? I know my battery charge frequently runs down low because when I am working around the garage I usually have the GT's stereo on. Every so often I need to hook up the battery charger to charge it up again. But the gauge indicator is always in the same position, just past the middle. If the gauge was actually working it should move to the higher end of the gauge when driving showing the alternator is charging up the battery, right?