You should find out the reasons why car battery dies to avoid the inconvenience of being stranded with a car that won’t start. Our article will delve into the world of battery drainage to help you understand why your car’s power source is failing.
This issue may be caused by simple oversights or complex issues within the car electrical system. Sometimes the car refuses to start yet you it had a perfectly working battery when you parked it.
Most drivers experience a dead battery once in a while. It is not an abnormal occurrence. However, there is cause for alarm if this happens many times.
Why car battery keeps dying.
You can personally resolve some of the issues that we are going to discuss below. Before deciding that its car battery replacement time, ensure that you look into items on the following list.
The car battery sustains the car’s electrical operations when the engine is off. It powers interior car accessories and other electrical appliances like the vehicle’s lighting.
Further, it is very essential during the process of starting the engine. Therefore, when the car won’t start, most people suspect the car battery. However, the cause could also be ignition system problems.
a]. Loose or corroded battery connections.
Car battery corrosion appears on the battery terminals. Car battery corrosion refers to the accumulation of crystal like substance around the battery terminals.
Battery corrosion is caused by a chemical reaction between the terminals, surrounding air and the sulfuric acid electrolyte inside the battery. That’s why it’s referred to as battery sulfation.
If its left for a long time, car battery sulfation will hinder the flow of electric current. Therefore, it’s a disconnection of the battery from the car’s electrical system.
Causes of car battery sulfation.
Car battery corrosion takes a while to form as it starts small and builds up within a span of days. Because the chemical reaction takes time but this depends on a number of things.
- Exposure of the battery to moisture.
- High humidity weather conditions.
- Poor car battery maintenance.
- Impurities on the battery terminals.
- Loose battery terminal connections.
How do you treat a corroded car battery?
This will require you to constantly perform a battery inspection. It will help you to note when the battery terminal crystallization starts to form.
Next, you need to clean the corrosion off the terminals. Otherwise, the corrosion will interfere with the battery voltage that reaches the electrical system.
There are two basic cleaning agents that you can apply in the cleaning process. These are inclusive of a special battery terminal cleaning product and a mixture of baking soda and water. Start by disconnecting the car battery terminals properly and then use a brush with strong plastic bristles to scrub.
b]. The battery is weak.
A weak car battery will not serve the purpose you need it to in the vehicle electric system. It is unable to hold battery charge for a substantial amount of time.
Therefore, battery discharge is common when your car battery is weak. Battery depletion happens at the slightest use of its voltage. Oftentimes, the car won’t jumpstart for you when you have a weak battery.
However, if it happens to jumpstart successfully, the alternator will charge the battery. But once the engine is off, that charge will be lost to battery discharge. At this stage, it’s safe for you buy a new car battery.
How do you know if you have a weak car battery?
The following is a lost of some things that will show you that your car battery is weak.
- Dimming headlights, interior lights and dashboard lights.
- Difficulties when starting the engine.
- Frequent jumpstarts.
- The battery faces performance problems during cold weather.
Weak car battery causes.
There are a few things that can cause the battery not to hold charge for a long time. Some of them can be avoided, hence, prolonging your car battery lifespan.
- Old battery will experience battery discharge.
- Insufficient charging by a faulty charging system.
- Defective battery.
- Car battery failure.
- High electrical load.
c]. Parasitic drain.
Parasitic drain involves the slow continuous loss of car battery charge when the car engine is off. Remember that when the engine is off, the car’s charging system is not functioning.
Therefore, any electric current demands within the vehicle will be met by the car battery. Full car battery charge amounts to 12.6V. This is enough to cater for any electric demands when the engine is off but only for a limited amount of time.
The amount of time varies depending on the car battery guide that’s provided when you buy a new car battery. Alternatively, you can find this information within the car owner’s manual.
What causes a draw on a car battery?
When referring to car battery parasitic draw, the factors at play are quite a number because every car and battery is unique. However, this list will show some of the common causes of parasitic draw.
- Faulty electrical components that draw charge from the battery.
- Overuse of electrical accessories when the car engine is off. For example by leaving lights on.
- Short circuits that draw power from the car battery.
d]. Faulty charging system.
A vehicle’s charging system is an electrical system component whose function is to charge the car battery when the engine is running. Additionally, it supplies electric current to the car’s electrical appliances.
What are the components of a vehicle charging system?
Note that it’s functional only when the engine is running. Vehicle charging systems consists of Voltage regulator and the alternator.
The voltage regulator monitors electric current flow from the alternator to the car battery and other electrical appliances. Therefore, it prevents car battery overcharging as well as undercharging.
Secondly, the alternator turns the alternator pulley so that electric charge generation can take place. It’s also known as the car generator. Once electric current production takes place, its supply goes to all appliances including the battery.
What are the signs of car charging system failure?
Failure within the car charging system will cause the car battery to die due to inadequate recharging. In fact, this may also lead to a bad car battery that is prone to battery discharge.
Investigate the car charging system whenever you observe any of the following things;
- Car battery electrical charging system warning light.
- Dim and flickering interior and exterior vehicle lights.
- Depletion of car battery charge hence causing engine starting difficulties.
What can drain a car battery when the car is off?
Car battery drain could be as a result of a faulty electrical system, oversight or a defective battery. Cars experience power drain during storage when the engine is off. Because the charging system is active when the engine is running, therefore, there is no voltage drop.
a]. Parasitic drain.
Parasitic draw refers to the continuous use of battery charge when the engine is off. Electrical system appliances are usually responsible for this issue. For example, leaving lights on, alarm systems, vehicle sound system among others.
If you don’t turn them off when the engine is not running, they will cause car battery drain. Therefore, the battery will die when the engine is off.
b]. Short circuit.
They are a result of electrical system malfunction whose cause is faulty wiring, loose battery cables connections and faulty electrical system components. When a short circuit happens, it leads to the creation of unnecessary power paths which drain the battery.
c]. Extreme temperatures.
The car battery shows negative performance during extreme temperatures. Whereby, high temperatures cause battery degradation while extremely cold temperatures alter the battery’s internal components. Therefore, causing the battery depletion when the car engine is off.
d]. Old battery.
An old battery refers to a case whereby the car battery’s lifespan is over. Most car batteries last between 3 to 5 years. Such a battery is susceptible to car battery drain when the engine is off.
e]. Electrical system malfunction.
There are a few electrical system components that can malfunction within the car. For example, faulty voltage regulator, faulty starter motor, alternator problems. They will cause power drain during storage when the engine is off.
What are the main causes of battery failure in a car?
Battery failure refers to a situation where the car battery is not able to supply power to the electrical system components. For example, the headlight bulbs and other electrical appliances. This is a result of the following issues which are similar to the causes of battery drain.
a]. Battery age.
If you’re using a battery for more than 3 to 5 years, it will start to fail your electrical system needs. That’s because the battery will be unable to hold charge for a long time. It will be susceptible to battery discharge and you will have to jumpstart your car multiple times.
b]. Improper battery maintenance.
A car battery guide advocates for proper car battery maintenance in order to achieve performance and lengthy lifespan. There are batteries that require regular maintenance while others don’t require maintenance.
However, regular inspections will help you to identify any issues that may be present. For example, battery corrosion buildup and loose car battery cable connections.
For regular maintenance batteries, ensure that the electrolyte levels are sufficient. Neglecting these maintenance requirements will cause car battery failure.
c]. Insufficient charging or overcharging.
This may result from a faulty charging system. This is in relation to alternator problems. Further, this may result from a faulty voltage regulator. Incase you have a new car battery, these will cause gradual battery degradation and eventually leading to battery failure.
d]. Deep battery discharge.
A car battery discharge refers to situations where the battery voltage becomes used up completely until none is left. When this happens oftentimes, it causes car battery degradation. Meaning that the next thing will be battery failure.
e]. Excessive vibration.
Excessive vibrations means that there will be physical damage to the car battery. There are many causes of car vibrations, however, not all of them affect the car battery.
When the battery is rocked while in its slot may lead to battery failure. Because the vibrations cause loose battery connections and they interfere with the chemical composition of the battery. A combination of these two factors leads to battery failure.
f]. Electrical system malfunction.
Electrical system issues result from components that are not in the right condition. For example, wiring, charging system problems, cables, appliances, fuses amongst others.
If there is a problem within these components, it leads to car battery draw. Next, this causes battery depletion and it has to be jumpstarted multiple times. Therefore, leading to battery degradation and failure.
Reasons why car battery dies while driving?
The vehicle’s electrical system components get power from the alternator when the engine is running. Therefore, a case of the battery dying when you’re driving is a rare occurrence. However, this list shows you what causes this rare occasion. In case this happens, a battery warning light will show up on your dashboard.
a]. Alternator problems.
The alternator is turned by the alternator belt in order to keep your car alive when the engine is running. It is a generator that produces electric current for the car battery and other electrical accessories.
A faulty alternator will not produce sufficient power. Therefore, this electric current will not be enough for recharging the car battery and for use by electrical appliances. In such cases, gradual car battery drain will occur and eventually, the battery will die.
b]. Faulty alternator belt.
The alternator belt connects to the engine’s crankshaft and its purpose is to drive the alternator. For the purpose of producing electric current when the engine is running.
Some people use the term alternator belt to refer to timing belt. In some modern cars, they are one and the same thing. However, there are car engines that have both of them to serve different purposes.
If the alternator belt is worn out, loose or broken, there will be interference of electric current generation by the alternator. This will cause the car battery to die when you’re driving.
c]. Electrical system overload.
High electrical load in relation to the overuse of electrical accessories may interfere with the vehicle’s charging system. That’s because it overwhelms the alternator’s charging capacity.
Therefore, the overuse of electrical accessories will drain the battery at a faster rate than the rate at which alternator charges it. This will cause the battery to die while driving.
d]. Battery age.
Old batteries will not hold charge for a prolonged period. This is despite being under constant charge by the alternator when the engine is running.
The car battery drain within old batteries will occur at a faster rate than the charging rate. Therefore, the car battery will die even when you’re driving.
e]. Electrical system wiring issues.
Electrical system problems associated with faulty wiring will cause the car battery to die when you’re driving. Faulty wiring leads to issues such as short circuits. These will cause a car battery drain hence causing the car battery to die when you’re driving.
How do I know if my alternator is draining my battery?
The alternator is a generator whose responsibility is to produce electric current for use by electrical system components when the engine is running. performing a simple test will show you whether the alternator is draining your car battery.
There are occasions when car battery drain occurs due to a faulty alternator diode. This is one of the causes of a parasitic drain. If this happens, the following are some of the different amperage battery drain tests that you can do.
- The amperage battery drain test.
- Voltage drop battery drain test.
- The bad alternator diode test.
- Car battery hydrometer test.
These tests will point you to what is causing voltage drop in your car battery. They will require you to use a digital multimeter. A multimeter will cost you around $20 dollars.
a]. Prepare for the test.
These are the things you will do in order to find the correct measurement. Failure to do this will give you a false reading. Therefore, do the following things;
- Turn off all the accessories and lights and remove the key from the ignition.
- Next you will disconnect one of the battery cables. If you’re unaware of the right cable to disconnect, this guide on how to charge a car battery will inform you.
- Clean the battery and remove corrosion from the terminals.
b]. The bad alternator diode test.
A bad alternator diode also referred to as a faulty voltage regulator is one of the causes of battery drain overnight. It also causes your lights to appear dim and the dashboard display will be flickering.
A diode will convert the alternate current coming from the alternator into direct current. A diode allows one sided flow of electric current. That is from the alternator to the battery and other electric appliances. Furthermore, it prevents current from flowing towards the alternator from the battery and other circuits.
If there is a failure of the diode it interrupts continuous flow of electric current to electrical appliances. Therefore, leading to dim lights and battery drain when the engine is off. The following steps will help to determine if your alternator diode is faulty.
Step 1.
Make sure that the battery terminals are connected. Also ensure that the connection is fitting and there are no corrosion that could interfere with the current flow. Adjust the voltmeter reading to a low setting on the alternating current voltage scale.
Step 2.
While the battery is connected, start the engine and let it run for a minute or two. This is in order to allow the alternator time to generate sufficient voltage for the battery and other electrical appliances.
Step 3.
Touch the multimeter probes to the battery terminals. Make sure that the engine is still running. Match the multimeter’s terminals to the battery’s terminals. That is the positive multimeter probe should be on the positive terminal and the negative probe on the negative terminal.
Step 4.
This is where you assess the reading. The presence of the slightest alternate current indicates faulty diodes. Where the amperage reads over 0.5 Alternative Current Voltage, there are more than one faulty alternator diodes. Therefore, a replacement of the alternator rectifiers or the diode will have to take place.
c]. The amperage battery drain test.
The goal of this test is to locate voltage where there should be none. For this test to be successful you will need to use an inductive ammeter capable of reading DC milliamps.
Make sure that no circuit is active when conducting this test. Because an active circuit puts the ammeter at risk of damage. Another precaution will involve the use of a memory saver. Whose purpose is to preserve the settings of your car’s computer and electrical appliances.
This type of amperage battery drain tests is suitable for older model vehicles. Older models were equipped with one or two computer modules. Newer cars usually have more than two control modules.
Therefore, conducting the amperage battery drain test may take up to 30 minutes before starting. Because that’s how long it takes for the multiple control modules to turn off.
Once they’re off the test may start. However, one or more of the control modules may awaken during the test.
Step 1.
Start by disconnecting the negative battery cable from the terminal. This move disconnects voltage flow to and from the battery.
Step 2.
Connect the positive cable of the multimeter to the battery’s negative terminal. Set your multimeter to the highest setting on the direct current amperage scale. Turn on the multimeter.
Step 3.
The next step is to adjust the scale on the multimeter. Make sure that your meter’s display reading is zero. Adjust the meter’s dial to a lower amperage scale.
Continue with adjustments until a voltage is detected. Vehicles without any parasitic drain will have a voltage that’s around 50 milliamps. But this varies depending on the year of manufacture because modern cars might exhibit a higher amperage.
However, on a vehicle with parasitic drain, the voltage reading will be much higher than 50 milliamps. If you’re using GM vehicles, the maximum draw will be obtained by dividing your reserve capacity 4.
d]. Car battery hydrometer test.
This is the best battery health check procedure. The results you obtain inform you about the condition of your car battery cells, whether your car battery is fully charged or it needs charge.
This test can only be done on batteries that need frequent maintenance because they have removable caps. However, a free maintenance car battery will require you to visit professionals who can test it for you.
A hydrometer is a tool that tell you if your battery needs charging or it’s defective. Car battery problems are difficult to diagnose especially problems that relate to parasitic drain.
e]. Voltage drop battery drain test.
The amperage battery drain test is very effective in modern vehicles. However, earlier car models have several computer modules that stay active 30 minutes after turning off the engine. Therefore making the amperage drain test in-effective.
In fact, one of these multiple modules could be causing the battery drain. Therefore, disconnecting the battery when conducting an amperage battery drain test may shut them off completely. In which case you will not get the correct test results and the drain will continue as soon as you reconnect the battery.
For those reasons, we recommend a voltage drop test. It is an effective method of identifying a faulty circuit that works for both earlier and modern vehicles. First, ensure that your car battery is fully charged. Secondly, make sure that the digital multimeter probes can reach the test points on each fuse.
Step 1.
Prepare your vehicle for the test. Read the owner’s manual to confirm the amount of time that every computer module takes to shut down completely. Further, confirm whether either of the modules has an on and off cycle. Voltage drop reading should take place when these computer modules are off.
Step 2.
Your digital multimeter device has a millivolts scale that you’re going to adjust. After setting it to millivolts scale, turn on the multimeter device.
Step 3.
This is the testing phase. You will begin by testing the fuses for the stereo, dashboard clock or computer circuit. They usually have a small current passing through them.
Use either of the multimeter probes to touch one test point at the back of the fuse and place the other probe on the other fuse test point. Afterwards, watch you multimeter’s display.
Note the readings somewhere because they will act as a reference. There is current flowing through the test points therefore, the reading you obtain is important for a successful test.
Test the fuse box under the hood then test the fuses under the dashboard. Note any voltage drop amount, the amperage rating and the circuit it protects. You will find the problematic circuit where the amperage rating exceeds the normal current draw of your vehicle found in the owner’s manual.
If you find that there is no voltage drop, then your vehicle may have a faulty charging system or a defective battery. Alternatively, a voltage drop will trigger you to find potential short circuits or wiring problems.
How do I know if my alternator is bad?
A bad alternator will not generate sufficient voltage for electrical appliances and it will cause inadequate recharging of the car battery. There are several things that will point to a bad alternator. We will list them below.
a]. The smell of burning rubber.
This burning rubber smell will originate from the engine area. It will be an indication that the alternator itself is overheating. Alternatively, it will tell you that the alternator belt is slipping.
b]. Strange noises from the engine area.
Pay close attention when you start the engine and identify whether there are whining, squealing or grinding noises coming from the engine area. Such noises are an indication of worn out bearings or faulty belt tensioner.
c]. Malfunctioning electrical system.
The alternator, sends electric current to the vehicle’s electrical system. For this reason, you will notice that the components of the electric system are misbehaving. These are inclusive of the stereo, dashboard gauges, malfunctioning power windows and door locks. This is a result of inconsistent power supply by the alternator.
d]. Defective battery.
A faulty alternator will interfere with the battery charge that’s being delivered to the battery. Meaning there will be inadequate recharging of the car battery.
Therefore, you will face a weak or dead battery and vehicle starting problems. Once you undertake battery replacement and the new battery keeps dying, investigate the alternator.
e]. Battery warning light.
Every vehicle has a battery warning light that comes on momentarily when you start the engine. However, if this dashboard warning light stays illuminated after the engine starts, it indicates a problematic battery. Alternatively, it could also indicate that there is a problem with the car’s charging system.
f]. Dim and flickering lights.
Ensure that the engine is running before making this observation. You may notice that the dashboard lights, interior lights or headlights are dimmer than usual and they’re flickering. This is an indication of insufficient power supply by the alternator.
How do I know if my starter is draining my battery?
When your car starter is faulty, it will cause engine starting issues as well as battery charge depletion. There are tests and signs that will point out the issue of a problematic starter.
The starter consists of small motors that are powered by the battery in order to start the engine. A starter solenoid supplies voltage to the car engine’s starter motor. When you turn on the ignition, the engine cranks and turns over thanks to the starter.
This is possible because the starter turns the internal combustion engine to initiate operation. The different types of starters are inclusive of hydraulic, pneumatic, and electric starters.
How can I test my starter?
There are a few tests that you can conduct to determine the condition of your starter. You can conduct a bench test but such tests will require the use of a special device. If you’re not well equipped to perform these tests, get a professional to do it for you. The other tests will involve checking the pinion and electric circuits.
a]. Checking the pinion.
This is one of the simplest tests. Turn on the headlights to ensure that the battery is functioning. Next, try to start the car. If the car engine cranks like its about to start and the headlights turn dim, the starter pinion is faulty. It could be stuck.
However, if the car just makes a clicking sound and there is no engine cranking, the problem could be the battery. Even the headlights may fail to light up in this case.
Next, try turning the pinion stub using a spanner. Use your owner’s manual to locate these parts. The starter motor is housed within the cylinder and it’s bolted to one side of the engine block. The pinion stub is a small square stab that sticks out of the end of the cylinder. Use the wrench to turn it until it can move freely. Afterwards, try starting the vehicle again.
b]. Test the electrical system.
First start with a visual inspection of the battery terminals. Presence of any corrosion or dirt accumulation could be interfering with the transfer of voltage to the starter. Clean the terminals and reconnect them then start the engine again.
i]. Battery test.
Use a multimeter to test the battery. Set it to the DC setting and the dial to 20 volts. Place the red multimeter probe on the positive battery terminal and the black probe to the negative terminal. If the reading is above 12 volts, the battery is in a good condition.
ii]. Solenoid test.
Perform a visual inspection of the solenoid after concluding that the battery voltage is okay. If the car will not start yet the battery is okay, the problem could be the solenoid. A visual inspection will determine proper connection of the wires running to it. Next use a circuit checker to ensure that the current is running to the solenoid. The circuit tester should light up to confirm that there is a flow of current.
iii]. Bench test.
This involves removing the starter completely. Leave this job to the professionals if you’re not confident in your abilities. Unbolt the starter from the engine block and disconnect its wiring. Make sure that you mark all the wiring so that you don’t get confused when reconnecting it.
Next, you will need jumper cables. Connect one end of the positive jumper cable to the car battery and the other end to the thick positive post on the starter solenoid. Connect the negative cable to one end of the starter and the other end to the negative battery terminal.
Afterwards, get an insulated wire and strip both ends. Using one stripped end, connect it to the small terminal on the starter. Make sure that you hold the starter in place because once its connected, it will move around and produce sparks. Connect the other end of the stripped wire to the positive battery terminal and the starter pinion will start moving. However, if the starter is faulty, it will not move.
How do I know if my starter is damaged?
The different signs of a bad starter are inclusive of the following.
a]. Noise from the starter.
There are unusual noises that could come from the starter when you hit the ignition switch. If these noises are not followed by an engine crank then turn over, the starter has a problem.
b]. Lights are on but the car won’t start.
In this case, you will notice that the headlights and other vehicle lights will turn on. However, the engine will not crank nor will it turn over. In fact, even the dashboard lights will be operational while the engine refuses to cooperate. Try starting it several more times and see if there will be a change.
c]. Oil on the starter.
During routine engine checks, you may notice that there is some oil stains on the starter. This will prevent it from proper operations. It results from oil leakage. Therefore, clean the starter and investigate the oil leakage issue.
d]. Funny odor and smoke.
When something is burning around the engine during the starting process it will produce a strange smell. If the condition is worse, you will note smoke coming from the engine.
Stop attempting to start the engine immediately. Exit the vehicle as fast as possible and call a professional to investigate the issue.
e]. The engine refuses to start.
This is an obvious indication that you’re having a faulty starter. However, a few other things could cause this problem. Therefore, a thorough investigation of the issue should take place first before making a conclusion.
What can damage a starter?
- Corrosion on car batteries.
- Oil leakage.
- Faulty fuse and bad relay.
- Problematic parts of the starter.
- Car battery corrosion.
- Dirt or accumulation of corrosion on the starter.
- Faulty wiring to and from the starter.
Signs of a bad car battery vs alternator.
In order to know the difference, you will have to be aware of the different signs of a bad battery and a bad alternator. We will provide a suitable list below.
| Signs of a bad battery | Signs of a bad alternator |
| 1. Clicking sound during engine ignition. | 1. Battery warning light stays illuminated. |
| 2. Slow engine cranking without turn over. | 2. Brighter than usual or dim headlights. |
| 3. Battery or check engine dashboard warning light. | 3. The smell of burning rubber. |
| 4. Swollen battery case. | 4. Noises under the hood. |
| 5. Irritating smell of sulfur like rotten eggs. | 5. Weak battery that dies repeatedly. |