Alternator Car Battery Voltage Chart

A reduced output may be a sign that the alternator is failing but the drive belt and wiring should be inspected before replacing the alternator.

Alternator car battery voltage chart. When a car drops for instance from 12 6 to 12 0 there will be 75 difference. An alternator is a must for all modern gm vehicles to operate. If the above fails try this. An alternator should put out between 13 5 and 15 volts of power.

Get into the car. A fully charged car battery voltage should be 12 6v or above this is with the engine off. The other critical tool to effectively diagnose an alternator is a scan tool. 12 volts is the standard automotive battery in today s vehicle and each of the battery has 6 cells with a voltage of 2 1.

The last number is 13 5v which is vt or the voltage that the alternator was held at during the test. It also controls electrical power to the vehicle s different electrical systems. The battery light on modern vehicles however is controlled by data and trouble codes. The steps may be different in more modern mercedes cars w212.

If it creates too little or too much voltage. This is enough to destroy the car s battery and electrical system. 13 5 volts is the bare minimum. Over 14 5 volts can cause serious damage to the alternator and car battery.

Under that and the car installation and battery isn t getting enough electric power. The alternator creates direct current measured in volts to achieve this. It is responsible for keeping the battery charged in the car which in turn keeps all the electrical systems functioning properly. There is a very big difference when a car battery drops even a small amount of voltage.

This value represents the voltage coming from your battery. Start the engine to check the voltage from the alternator. After taking the voltage output reading remove the tester cables from the battery poles and remove the multimeter. Close the battery casing holder.

The alternator should be tested with the engine idling and electrical accessories such as the radio and headlights turned off. A fully charged car battery has 12 6 volts. Since an alternator s output can vary both up and down from 13 5v in real world situations it s actual output limits will vary from the idle and rated numbers. Put the key in the ignition and turn to position two right before you start the car.

On older vehicles the battery light would turn on the alternator light when the alternator output or battery voltage dropped below a preset value.