Can an alternator be intermittently bad?
Yes. However, a car will only be able to run on a bad alternator for a short period of time. Since the alternator is responsible for charging the battery when the engine is running, once the battery is drained, the vehicle won’t start.
Can a car battery fail intermittently?
Bad batteries will lose their surface charge after each consecutive start. By looking at the preceding, even an intermittently bad battery, due to temperature or anything else, can be diagnosed. Batteries that are getting weak should be replaced as a matter of maintenance.
Why would a alternator over charge?
When the wrong alternator has been installed in a stock vehicle or if the pulley has undersized dimensions (causing extra alternator rotation), the charging supply will be higher than the demand and cause an overcharged state. High performance or racing alternators should not be installed on stock passenger vehicles.
What would make an alternator overcharge?
An overcharging automotive alternator can be the fault of the voltage regulator, an accidental electrical path causing the field windings to be powered independently of the regulator (bypassed) or the sense circuit to the regulator not properly providing the correct battery voltage to the regulator.
How to tell if battery or alternator problem?
A simple test to check the working of the alternator is by running your car; and then unplugging the positive connection of the battery. If the car stops, then you most likely have a problem with the alternator. Another simple test is to check your interior lights.
How do you know if alternator is bad or battery?
If your car starts but stalls when you’re underway, your battery is probably not being recharged due to a faulty alternator. A squealing sound coming from the engine that gets louder when drains like the heater or sound system are on may be your alternator bearings.
What does it mean when your alternator stops charging the battery?
Indicator Light On. Usually, the first sign that your charging system is in trouble is a “battery,” “ALT,” or “CHARGE” warning light illuminating on your instrument panel while driving. It means that for some reason, the alternator has stopped charging the battery and your car is running on battery power.
What happens if you start your car without an alternator?
If you were to try and start your vehicle without an alternator, the battery alone would not be able to produce enough power to get the engine running. Even if you had a new car battery and were lucky enough to turn the engine over, it would probably run for about 10 minutes before the power cuts out.
How often does a car alternator need to be charged?
Alternators and batteries do not last forever, and each have their own lifespans. A car battery will last from 2 to 5 years, depending on how often you drive and the climate where you live. Batteries generally last longer in colder environments and shorter in hotter environments. Alternators will last about 7 years or every 80,000 miles.
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.