What to look for in an alternator battery test?
1. Alternator Output Test II. Battery Testing 1. Inspecting the Battery III. Checking the Drive Belt Bad charging and starter system’s connectors and wires. Corroded or loose battery terminals. Low battery electrolyte level. Faulty battery. Blown charging circuit fuses or fusible links. Worn out or loose drive belt. Loose alternator mounting bolts.
What are the most common problems with alternators?
One of the most common problems on an aging alternator arise from worn out brushes. But a charging circuit blown fuse, a broken fusible link, a failed diode in the alternator’s rectifier assembly, even a worn out bearing will affect charging system operation.
What happens if you have a bad diode in an alternator?
A malfunctioning diode in the alternator can create a parasitic drain on a car’s battery. Diodes should allow current to pass in only one direction, but a bad diode will keep the charging circuit open even when the engine in not running, allowing the battery to go dead. This often happens overnight.
Can a bad car battery cause an alternator to not charge?
In theory a car can run only with the alternator charge, but this can cause heavy voltage spikes and other strange symptoms so this means that a bad car battery can cause an alternator to not charge also. Cars are increasingly coming with modern electronics.
What happens if you cant test your alternator?
If your battery is too low or damaged, then you won’t be able to start your vehicle. If you can’t start your vehicle, you can’t test the alternator – it’s a vicious circle. Without being able to turn on your car, you can’t use the voltmeter to check the electrical power within your vehicle.
A malfunctioning diode in the alternator can create a parasitic drain on a car’s battery. Diodes should allow current to pass in only one direction, but a bad diode will keep the charging circuit open even when the engine in not running, allowing the battery to go dead. This often happens overnight.
How can I tell if my alternator is in high gear?
Start the vehicle and rev the engine to 2,000 RPM. This will draw power on your battery, which should cause your voltage regulator to kick the alternator into high gear. Keep the engine running and retest the battery with the voltmeter. When you read the voltmeter this time, the voltage should go up to at least 13.
Why does AutoZone test the alternator and charging system?
Keep in mind, when you test your charging system while the car is running, or AutoZone does the same, the system voltage is being tested at the battery, and if it’s not getting a charge, the test cannot determine why. Either the alternator itself is at fault, or the wiring between it and the battery are.