It’s a struggle when you realize that there is a problem and your car is not starting. Several causes may trigger a car to not start.
It could be the starter; the battery and it could also be owing to the alternator of the car.
Can an alternator cause a car to not start?
A bad alternator can cause a car to not start owing to the battery. An alternator generates electricity, distributes, current, and recharges the battery which in turn starts the engine. With a bad alternator, it is possible to jump-start a car but not possible to continue driving.
Simply put, an alternator in the car is a generator that recharges the battery of the car and does so by generating and distributing energy.
To start a car, the battery needs to be charged. In turn, to keep the battery charged, the car needs a working alternator.
If the alternator fails, the car would jump start on the charge remaining on the battery but would soon expire down since the alternator would not be able to recharge the battery further.
Similar problems may occur when there is an issue with the starter but the major difference between a starter and an alternator involves how the energy conversion works.
An alternator works by converting mechanical energy to electrical energy as it powers through while someone is already driving.
On the other hand, a starter uses electrical energy and converts it to mechanical energy to get the wheels going.
When an alternator is out of order, other problems also start to show up on your car. You would notice certain electrical issues such as a diming or flickering light. Other than that, you may also expect the car to stall heavily even after a jumpstart.
How does a bad alternator affect car starting?
Primarily, an alternator works by generating electricity. Not only does it provide the electronic components with the required power, but it also charges and recharges the battery. The motor receives the current required to start as well.
When an alternator goes impaired, it would not be able to distribute current as required. Likewise, the alternator will not be able to recharge the battery required to keep the motor moving.
This is why, when an alternator goes bad, a car will start but would not have the charge to continue the drive.
Although a non-start can be a problem with a bad alternator, it is more common when the engine completely expires shortly after starting. It could expire as soon as a few seconds after the initial start.
If you replace the battery by keeping the same alternator in such a case, the car would start and continue driving for as long as the battery is charged.
Once the battery drains, and the bad alternator is unable to recharge the battery, the car would not start the second time.
Will a car start with a bad alternator?
With a bad alternator, a car may start but you can expect it to stall or stop after a few minutes.
Since the battery needs to be kept powered through the alternator, a faulty one would mean the battery is not charged properly.
Can a car start without an alternator?
A car can start without an alternator but not without a battery because it is the battery that provides the motor its power. Having mentioned that, a car cannot be driven or started again if it stops if there are no alternators.
Without an alternator, the battery has to be fully charged. Without the current supply from the alternator, the battery would not have the charge to power the motor any further.
How to check the alternator if the car won’t start?
There is a simple way to check if your alternator is working fine. Here is how to test an alternator if your car won’t start:
At first you need to carry out a voltmeter test for which you need a working voltmeter.
Clean the alternator terminals before the connection. The black cable goes to the positive terminal and the red goes to the negative.
Keep the engine turned off as you measure the voltage that should be from 12.5 to 12.8 v. You would need to recharge the battery if the voltmeter reads anything below that.
Next check the voltmeter readings once you start the engine. Now the reading should be around 14.2 to 14.7 v.
Now turn on all the other electronic connections like lights, and fans to see if the reading drops. It should not drop further than 13 v.
Next, turn off the engine and notice if the reading is above 12.6. If this is the reading, your alternator is good to go.
How do you know if it’s the starter or the alternator when the car won’t start?
Generally, there is a fine line between how an alternator works and how a starter works. Although the principles and operations of the two-car parts are quite different, they exhibit similar signs and symptoms when the parts go bad.
Below are some of the ways to tell whether it is the starter or alternator that needs to be looked at when your
Check the lights :
One effective way of telling whether it is the alternator or starter is by checking on the lights. Since the alternator powers the electrical components in the car, if you notice dimming light, you would know it is the alternator.
Check dash light :
If you are struggling to start the car but notice that the dash light is shining bright and clear, the problem is with the starter.
Jump start the car :
If your car is not starting, it is most likely that you would want to jump start your car. If jump starting does not produce any response from the car, you would have to assume that the starter has gone bad.
Burning rubber smell :
Oftentimes, people who face problems with their cars starting complain that there may be a burning rubber smell coming from the engine. This smell indicates a problematic belt, relating to an issue with the alternator.
Engine noise :
You can also tell whether it is the alternator or starter by distinguishing between the noises coming from the engine. When there is a bad alternator causing the car not to start, you would hear grinding noises from the engine.
On the contrary, when there are clicking noises coming from the engine when you attempt to start the car, the starter may be the culprit.
How to jump-start a car with a bad alternator?
Thus, you would always need to know what to do and how to jumpstart a car with a bad alternator. The following steps tell you how to do it:
Before anything else, you would need to remember that there is no jumpstarting with a drained battery or a bad alternator with another battery that is fully charged.
So first would need to find another car with a fully charged battery. You may also want to jumpstart your car on a day when the sun is out and about.
With your car shut off, make sure to run the engine of the fully charged battery a couple of times. Before you do so, also connect the jumper cable between the two cars.
Before jumpstarting, you should also ensure that every possible electrical or electronic connection is switched off. This, not only includes the heater and cooler but also the chargers and GPS of the car.
This is important because the computer system takes up power from the alternator or the batter and shutting them off would conserve power when the alternator is bad.
First connect the red cable of the second car to the positive end of the bad that needs a jump start. As for the negative or black cable, dot it to the positive end of the working or second car
For the black cable, you need to ground the open end of the cable. This end of the cable should be grounded on a non-painted part of the engine but never on the battery
Now start the second working car and run for a couple of minutes before starting the car that has a bad alternator.
Finally, remove the connected terminals and keep the positive and negative ends of the cables separately.
This should jumpstart the car with the limited charge on the battery. Hence you should immediately head to the mechanic to get your alternator fixed
A bad alternator can cause several problems to the car and one of them is a car struggling to start because the battery cannot be recharged. Moreover, a stalling car or a car with electronic problems like a dim light and faulty air conditioner are other problems of a car with a bad alternator.
I am an automotive enthusiast and have been interested in cars since I was a little kid. I have worked in the automotive industry for many years and have extensive knowledge of vehicles and their engines. I am a father of two and I love spending time with my family.
Read more about the author here.