Mazda Protege alternator charging issue causing battery voltage to spike to 18 volts with troubleshooting steps attempted on Mazda Protege

Some Mazda Protege owners report experiencing alternator charging issues that cause battery voltage to spike to 18 volts. This problem may stem from a faulty voltage regulator, which can lead to erratic voltage spikes if not functioning correctly. Additionally, owners may find that the alternator's output voltage is outside the normal range of 9 to 13.5 volts, indicating potential issues with the alternator itself. Inspecting electrical connections is crucial, as damaged connections can contribute to charging problems. Variations in battery voltage readings under different conditions may also signal underlying issues with the charging system. Furthermore, the condition of the alternator belt should be evaluated, as a worn or stretched belt can hinder proper charging. Monitoring the charging voltage while the engine is running is essential, as excessively high levels can shorten battery life. It is advisable for owners to follow these troubleshooting steps to identify and resolve the alternator charging issues effectively.