You are certain that you left your car with a full battery, and suddenly it won’t start. Your battery charger says fully charged, but the car won’t start. What could cause this?
There are a couple of causes for this, and we will go through the most common ones. Sometimes, a dead battery sends a readout but cannot start the engine. Then, there are problems with corroded battery terminals. Often, loose connections or a power drain from other electrical components can cause this problem. Last but not least, a faulty starter or an alternator can cause this problem.
When your car gets into this state, it is important to diagnose the underlying issues. That is the best and the most economical way to get your car back on track. We will go through the diagnostic process and answer the most common question relatable to this issue. Stay with us.
Types of Battery Chargers and Its Indicator Accuracy
There are several types of battery chargers that work on different principles:
- Electrical chargers. These are the most common chargers that can tune up the battery quickly. There are a number of chargers, and you should choose one based on your battery. Check the amp hour rating of your battery, and choose a charger that has between 10% and 25% of that rating.
- Solar-powered chargers. These chargers are more expensive and not as strong as electrical chargers. But, they are good at maintaining the battery power.
- Trickle chargers. They are used to supply the battery with a continuous power flow. It is a good choice if you are not planning to drive for a long time.
- Battery maintainers. Like trickle chargers, battery maintainers keep the battery alive when it has not been used for some time. The main difference between trickle chargers and maintainers is that you do not need to disconnect the maintainer once it has finished charging.
The indicator is used to show the amount of voltage and power left in the battery. The battery measures amp hours that go to and from the battery and approximately measures how much capacity it has left.
The issue with the battery charger indicator and its accuracy is often connected to the battery and its state. If the battery is unloaded and hasn’t been used for some time, the indicator can show a realistic value.
The temperature also impacts the battery voltage level readout. A cold battery that is 50% full will have a higher voltage than the same battery at a hot temperature.
Common Reasons for Car Not Starting with a Fully Charged Battery
Battery Terminals
Corroded battery terminals are a common issue that can cause problems in starting a car. If these terminals are exposed to water or other outside factors, that can result in corrosion. If the corroded battery terminals are the issue, they can cause resistance. In case of resistance, the battery may be unable to deliver current to start the engine.
Battery terminals can also be loosened, causing the same problem. If you notice this issue, address it and then try to start the engine.
Starter Motor and Ignition Switch Concerns
When you turn the ignition key on, the starter turns over the engine. If you have a bad starter, even a good battery cannot start the engine.
Also, an ignition system is a common culprit in these situations. If you can turn on the lights but not the engine, then you probably identified the ignition as a problem.
Electrical System and Fuse Problems
A faulty alternator is almost always the cause of this problem. The alternator is charging the battery while the engine is running. A bad alternator sometimes can keep 13 volts when the car is running but cannot supply them when starting the engine.
A blown battery fuse controls the flow of power in the circuit. They protect the circuit from high currents and power surges. In case it blows, then the car won’t be able to crank.
Fuel System Issues Affecting Car Start
If you cannot start the car, a blockage in the fuel filter or the fuel lines can be the cause. If the fuel is not reaching the engine, then it cannot run. Check the fuel system, beginning with the fuel tank. Check the fuel supply lines for any damage.
Check Out the Causes Why My Car Wont Start But Fully Charged:
How To Check If Car Battery Is Dead or Giving False Positive?
The most precise and easy way to check your car battery is with a multimeter. It is a cheap (around $10) tool that is easy to use.
- Remove the surface charge of the battery. To do so, the battery must experience a load of 20 amps for 3 minutes. Turning the high beam on your headlight will do the trick.
- Do a visual check of the battery and terminals. The terminals should not be covered in yellow or white corrosion. If so, that can be the source of the problem.
- Adjust the multimeter. Set it to a range of 20V DC volts
- Connect the multimeter. To do so, connect the negative (black) cable from the multimeter to a negative terminal on the battery. Connect the positive (red) cable from the multimeter to the positive terminal on the battery
- Check the multimeter readouts. A healthy car battery will show an output of around 12.5V. If the value on the multimeter is between 12.3V and 12.5V, it could use a charge. If the readout is below 12.2V then you have a faulty battery
- Turn on the car while the multimeter is still connected. A healthy battery will show a value of at least 10V. If the multimeter shows less, then the battery is not strong enough to power up the car.
Steps to Take If Your Car Won’t Start
There are a couple of makeshift solutions that can get your car to start.
If the car clicks but won’t start when you turn the key, you can do three things:
- Cycle the key. Turn the key to the starting position 10 times, then wait 5 minutes. If, after that, the engine won’t start, proceed to the next step.
- Tap the battery terminals. If you are stuck in the middle of nowhere without tools, you cannot fight the corrosion. The only thing you can do is tap the terminals and hope that they will get better contact. To do this, use the heel of the shoe.
- Finally, try tapping the starter. To do so, use a tire iron. Sometimes, the problem can be in the starter electrical contacts. Tapping the starter may resolve this issue and get the starter working again. If this proves to be a problem, it would be a good thing to check the contacts and replace them if needed.
If there is no clicking sound when you turn the key, try shifting the shifter. Move it to the neutral position, then try to start the engine. If that doesn’t work, move the shifter to the park and try again. Sometimes, the problem is in the transmission range selector, and this way, it can reestablish electrical contact.
Check Out Car Battery Drains Overnight Or After Days Of No Use! PARASITIC DRAIN:
When to Seek Professional Assistance
If none of the options above doesn’t help, then you may have a problem with a dead battery. The only solution is to call the tow truck and transport the vehicle to the mechanic.
Tips To Avoid A Car Battery Fully Charged But Car Won’t Start
Some car components have a work life, and you cannot do much to prevent failure. But there are other ways that you can postpone or avoid problems with a full battery that cannot start the car.
- Keep the battery safe from debris and humidity. Those can cause corrosion.
- Change the fuel filter regularly. If a fuel filter is blocked, the fuel cannot reach the engine and start the car.
- Do not let the fuel tank go empty. Without any fuel in the tank, the engine cannot start.
FAQs
What Voltage Is a Car Battery Considered Dead?
The car battery is considered dead if charged to less than 12 volts. A 12V battery reading on the multimeter is a sure sign that you need a new battery. There is no point in powering up a battery with this low readout.
Will a Battery Charger No Longer Charge a Dead Battery?
The battery charger may be able to charge a dead battery. You can choose a jumpstart, which will get your car rolling, or a slower, safer charge. The slower charge can take up to 24 hours, but it is a safer way to keep a healthy battery.
Can a battery be too dead to start
Yes, a battery can be too dead to jump-start. In most cases, a drained automobile battery can be jumpstarted. But, if there is no way to start the battery, it is too dead.
Can a Car Battery Test Good But Can’t Hold A Charge?
Yes, a car battery test can be good, but it still cannot hold a charge. Usually, the reason for that is an old and weak battery. Other reasons include a defective starter, faulty alternator, or a problem with the battery fuse.
Final Considerations
If you are having problems with the battery, but it shows that it is charged, you are dealing with a weak battery. The reasons can be in the battery itself, but sometimes the cause for this state is components like an alternator or a starter. It is worth checking the battery connections for rust, and while you are at it, take a look at the battery fuse.
In case you cannot determine what the problem is with the battery, test it with a multimeter. If it shows values below 12V, you are dealing with a dead battery. If you cannot handle this problem yourself, contact the mechanic and get your car back on the road!
