Battery Cable Alternator Test

To do a quick check on an alternator i was told that you could start the car and then remove the negative battery cable.

Battery cable alternator test.

Test alternator by connecting voltmeter on dc 20 red on positive battery terminal and black on negative battery terminal. Technically yes but that test can also wind up destroying all the electronics in your car. Now about the ineffectiveness of it the vehicle will run if the alternator is producing enough juice. With no battery in the circuit to act as a buffer the alternator can put out up to 150 volts depending on engine rpm.

Test the negative battery cable by using the same procedure as above for the positive cable but this time you will have the red lead of the multimeter touching the metal housing of the starter motor and the black lead of the multimeter connected to the negative battery terminal. Again you should see a reading of 0 3 volts or less to be. Testing alternator by removing battery cable can you test an alternator by removing battery cable. Dear tom and ray.

Pcm tcm electronic power steering radio etc. So when you test an alternator by pulling battery cable you increase the probability of killing that regulator. When the smoke clears that simple test could end up costing you several thousand dollars for new electronics. Start vehicle and voltage on voltmeter should increase to around 13 volts and stabilize there.

The second you disconnect the battery the voltage regulator pegs the alternator to put out maximum power. Doing this would allow you to check whether the alternator is putting out enough current to run the vehicle.