A vehicle’s alternator serves dual purposes in the proper operation of a vehicle’s electrical system. A properly operating alternator will keep the vehicle’s battery in a fully charged state, and it will supply additional electricity for the operation of the vehicle’s accessories as it is needed. Although a weak alternator producing inadequate current is more commonplace, it is also possible for too much current to be produced.

High Gauge Reading

An overcharging alternator will cause the voltmeter on the vehicle’s dash to read an overly high voltage that may or may not vary with engine speed. Normal readings should be high upon start-up, then settle into the normal range. An overcharging alternator, however, will cause the meter to remain in the high position after initial start-up.