If you notice that your car has starting problems or is stalling frequently, you might wonder if the problem is caused by a faulty alternator or battery. It can be hard to determine if you have an alternator or battery problem since these two components share equal parts in the car’s charging system. In starting and running the engine, the battery delivers a zap of electricity to the starter which starts the engine. Once the engine is running, the alternator will then do its job and recharge the battery. To know whether it is the alternator or battery that is causing the problem, you can bypass the battery’s role by jump starting your car. If the engine starts for a bit but dies after, the alternator might be faulty. If the engine keeps running after a jump start but won’t start again using its own power, then the battery is causing the problem.
Alternator or Battery: Does a Car Run Off the Alternator or Battery?
Since the alternator and the battery play very important roles in the car’s charging system, when a car is showing some starting problems, it can be hard to determine what caused the problem. This leads car owners to ask, is the problem caused by the alternator or battery? To know the answer to this question, we need to understand what is an alternator and what is a battery.
What is a battery?
When you insert the key in the ignition of your car and turn it on, a signal will be sent to the battery. When the signal is received, the car battery will then convert chemical energy into electrical energy. This power will then be delivered to the starter and distributed through the spark plugs which will ignite the engine’s cylinders. This starts the engine, converting electrical energy into mechanical energy, that allows your car to run.
If you ask, does the car run off the alternator or battery? Bear in mind that the battery literally provides the needed spark to get the car running and with the help of the car’s alternator, the car will keep on running. The battery also provides energy or power to the lights, radio, and other car accessories or systems that are electric-powered.
What is an alternator?
Since the car battery continues to provide power to the car’s electrical systems, you might ask, how does the battery do that and how come it doesn’t drain or die when it keeps on providing power? This is where the alternator comes in.
The alternator is a device that produces electricity. It plays a vital role in the energy cycle needed in the operation of your car. It provides the car the needed bulk of electricity and it also helps recharge the battery. How does the alternator do this?
As mentioned earlier, the battery converts chemical energy into electrical energy, then it will be converted to the mechanical energy that allows the car to move. During this phase, the alternator enters the cycle with the belt and pulley system. The movement of this belt, which is the mechanical energy, spins the rotor of the alternator at a high speed within the stator. As the rotor spins, electricity is made.
However, the electricity created by the alternator needs to be converted to a format which the battery can use. This is because car batteries work on one-way direct current or DC electricity while alternators output AC or alternating current electricity which sometimes flows in reverse. In order for the battery to use the electricity from the alternator, the power has to go through a diode rectifier to convert the AC into DC. Once converted, the battery can then use this power to recharge. Basically, the alternator will send this converted electricity back to the battery for storage. This is why the battery always has power to provide to the car’s electrical systems.
Alternator or Battery: How Do You Tell If It's Your Battery or Alternator?
If your car is having some starting problems, it can be hard to identify if the problem is caused by an alternator or battery. This is because they both have a role in the car’s charging system. It is the battery that provides the jolt of electricity to the starter motor which cranks the engine, but once the engine is running, the alternator will then take over and will recharge the battery.
So which one is causing the car’s starting problem, the alternator or battery? It is important to determine which one is faulty so you will know how to correct the problem. To determine which one is causing the problem, we will go through each of the signs of a faulty alternator and a faulty battery.
How will you know if you have a bad alternator?
You will know if your alternator is due for a repair or replacement when you experience any of these symptoms:
- Illuminating warning light.
Most modern cars have been installed with a warning light that alerts the drivers when there is an alternator problem. You may see a battery-like icon or an illuminating “ALT” or “GEN”. This warning light is linked to the car’s onboard computer. If the computer has detected that the voltage output of the alternator goes below or above the preprogrammed limit, the warning light will come on.
- Dead battery.
Since the alternator is the one that recharges the battery, when the alternator fails to function, the battery will die or be drained since it no longer receives electrical power from the alternator. When this happens, your car won’t be able to start, which can leave you stranded somewhere.
- Lights are dim.
The alternator helps the battery supply the power needed for your car’s electrical system. When the alternator starts to fail, the accessories of the car will also suffer. You may notice erratic signs such as the dimming of lights or extremely bright dash lights or headlights. You may also notice that your tachometers and speedometers stopped functioning for no reason at all.
- Flickering lights.
Flickering lights can also be an indication that your alternator is failing. You may experience this symptom together with the dimming of lights, but not all the time. If it seems that your lights have become bright, then dull, and bright again at random times, then you really have an issue with your electrical system and it can be caused by a faulty alternator. This can happen when the faulty alternator is not creating enough power to keep the lights going at its full strength.
- Difficult to start the car or the car is stalling.
Car starting problems or keeping the car running are some indications that you have some issues with your alternator. However, this problem can also be caused by some other faulty components or issues so it is better to have your car checked by a professional to get the right diagnosis.
If the starting problems are caused by a faulty alternator, this means that it has failed to recharge your car battery or not recharging it properly. This in turn, causes the battery to be no longer capable of starting the car since the power it has is not strong enough. This alternator issue can also cause your car to stall after it has been running. This can happen when the spark plugs are not receiving enough power from the alternator to keep the car going. It can be hard to determine whether this problem is caused by a faulty alternator or battery.
- Burning smell.
If your alternator is working way too hard due to some issues, it can lead to overheating. You will know if your alternator is overheated when you notice a burning smell, like there is a rubber burning. This burning rubber smell might be the rubber belt which keeps the alternator going. It can also be the wires’ rubber sheaths that connect everything in your car’s electrical system. This can happen when there is too much friction on the belt due to a misaligned or not freely turning pulley. This produces heat which will then emit a burning rubber odor.
- Unusual noises.
You may hear growling or whining noises when your alternator is failing. These noises can occur when the pulley is not aligned with the belt. If it is tilted on the shaft or the bushing and bearings are worn, you will hear these unusual noises which will alert you that there is something wrong. If the alternator is severely damaged and has caused damage to the engine, you may hear rattling noises from the engine due to broken engine bearings. When this happens, you may have to deal with a very expensive repair bill.
How will you know if you have a bad battery?
To help you determine whether a problem is caused by a bad alternator or battery, here are the common signs of a bad battery:
- Your battery is old.
A conventional car battery usually lasts for about three to five years. If your car battery is way older than that, then it means it is due for a replacement. A replacement is necessary since the old battery has lesser ability to hold a charge.
- Clicks but the car won’t start.
If you hear a click or there is a long crank when you turn the key in the ignition but the car won’t start, it can be an indication that you have a battery problem. However, this problem can be also caused by issues with the starter. You can try to start your car by giving it a jump start. It is best to have it checked so you’ll know what caused the problem.
- Engine is slow to start.
This is one of the obvious signs of a bad battery. When you turn the key in your ignition and the engine cranks, but makes a sluggish whirring sound for a much longer time than usual before the engine starts, then it is an indication that you have a bad battery.
- Corroded battery terminals.
When you do a visual check and you notice that your battery terminals are corroded, then it means that your battery has been compromised since this can impede electrical energy. This keeps your battery from getting a proper charge. You will have to have it checked by a professional or have it replaced.
- Battery is warped.
If you notice that your battery is warped or distorted in any way, then it means that it is due for a replacement. You should have it replaced immediately.
So how can you tell if it is the alternator or battery?
You can jumpstart your car to know whether the problem is caused by a bad alternator or battery. If the engine starts after the jumpstart and it keeps on running for a long period, but after turning it off the engine won’t start again, then the problem is your battery. You can have it tested or replaced immediately. If after jumpstarting your car, it starts but will turn off immediately, you may have a problem with your alternator. This means that the alternator has failed to recharge the battery.
If you notice any symptoms of a bad alternator, it is important to have it checked right away. This is because a faulty alternator can cause issues to your car battery since after the battery has successfully started your engine, the alternator will take over and charge the battery while the car is running.
If the alternator fails to do its job due to some problems, the battery will compensate for it and will supply the needed power instead of the power generated by the alternator. Since the battery is not designed or made to provide power for a long period, it can cause it to wear out, draining the power it has. When this happens, your car will stop to function.
Hopefully this article has answered your questions or any confusions about the car’s alternator or battery. However, bear in mind that no matter what caused problems to your car, you need to have it checked immediately to prevent any further damage.