What voltage should an alternator put out under load?

The voltage should read a minimum of 13 volts. A good alternator should put out between **13.5-14.5 volts. Stress test the alternator – Place a load on the alternator by turning on the headlights, the radio and the air conditioning. The voltage should remain high with these circuits on.

Why does my alternator not change the voltage?

If the voltage change and go back to normal when you tap it lightly with a hammer while the car is running – the Carbon brushes are worn out and needs to be replaced in the alternator, or the whole alternator. Sometimes there is an electrical problem in the alternator, and even if the voltage does not change, it might be damaged.

How does a voltage drop test work on a car?

A voltage drop test will assess voltage losses at the battery, the alternator and the starter. 1) With the voltmeter connected to battery, and key and engine off, record a “base” voltage reading. (Your battery should have a minimum of 12.4 volts.)

How can I tell if I have an alternator problem?

To differentiate an alternator problem from the battery, you will need to use a voltmeter to check for voltage. First, turn off the engine and check the battery voltage. A fully charged battery should have a reading of 12.65 volts. Next, turn on the engine and recheck the voltage. You should have a reading of 13.5 to 14.5 volts.

What should the voltmeter read when the engine is off?

The voltmeter should read around 12.6 volts with the engine off and 14-15 volts when the engine is running. If voltage is below 13.5, there’s a good chance the alternator is not keeping up with your battery’s charging needs. Solution #3: Check the alternator cables for abnormal wear, including cracking and fraying.

Can a loose alternator belt cause flickering lights?

If this symptom is consistent with the flickering lights issue, then a loose alternator belt is more likely the cause. One of the first symptoms that you should notice is the battery warning light coming on. This warning light does not always mean there is a problem with the battery itself.

What does it mean when your alternator lights go out?

When it’s a problem with the alternator belt, the flickering or dimming lights may stay consistent for quite some time before they completely go out since no power is getting to them. Depending on how old the alternator is, it can also be a sign the alternator itself is on its way out.

What causes an alternator to go over base voltage?

If you are getting more than 2 volts above base voltage, most likely your alternator is over-charging the battery or the battery is faulty. Other potential problems are a faulty voltage regulator or a problem in the charging system wiring.

How can I tell if my alternator has bad ground?

Preform the same test with the positive side. Place the red lead on the positive battery terminal (if possible dig it into the battery post, not the terminal). Place the black lead on the bad post of the alternator. Same thing as above, if the voltage is above 0.5v then examine the positive cabling for problems.