Why does the dash gauge switch from battery to alternator?

Why does the dash gauge switch from battery to alternator?

OK now that is starting to make sense. If the dash gauge switches over from reading battery voltage to alternator voltage after the engine starts, and there’s a diode between the alt. output and the battery, it would explain a lot. I will take readings at the alternator and let you know what I find.

Why is the voltage reading on my alternator going up?

While watching the voltmeter display, start wiggling wires at the back of the alternator, the battery, and the remote voltage regulator (if there is one). If the voltage reading on the meter display goes up while wiggling one of the wires, you’ve found a bad electrical wire or connection.

What makes my car voltage gauge read low?

As a vehicle slows, engine/generator RPM slows and the current (amperage) output of the generator may not be sufficient to supply the loads, the vehicle system voltage will drop and the lights will dim. Dimming of the lights is an indication that current is being pulled from the battery.

Can you test the battery with an alternator?

Click to expand… That’s battery cable trick. When cars had generators you could test the generator by running the car with the battery disconnected. It’s different with an alternator and with todays cars. You can spike the electronics very easily.

What causes high voltage in alternator?

You should get 0.5 to 2 volts higher than 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.

What is the voltage range of an alternator?

Alternators usually run 14.2 to 14.5 volts. You see you need a greater voltage coming from your alternator than the battery has to charge it. Normal charging voltage can vary from 13.5 to 14.5 volts or even higher depending on the battery’s state of charge, temperature and electrical load on the alternator [1]

How do you test alternator voltage regulator?

Test the alternators regulator with a full field test when the alternator has low output. This test will rule out the regulator by bypassing it and energizing the rotor with unregulated voltage. A Type-A circuit has the voltage regulator on the ground side of the field coil.

What should my alternator voltage be at?

Normal Output. An alternator should put out between 13.5 and 15 volts of power. The alternator should be tested with the engine idling and electrical accessories, such as the radio and headlights, turned off.