Did you know that car batteries charge while driving? As long as the engine is running, as long as the rotor revolves inside the stator, and as long as the alternator is provided with the proper amounts of mechanical energy, the batteries will charge.
This article will help you understand the basics of charging a car battery. Still, it will also be a huge help in choosing the right charger for your car battery, taking all the proper measures to maintain it, reading the values properly during, pre, and post charging, and most importantly, will help you treat your car battery the way it needs to be treated.
Of course, we will not go over the deep physics of how car batteries work using physical formulae, graphs, and complex diagrams. That would be too boring. But expect us to be covering all the basic principles and mechanics so that by the end of this post, you’ll have a comforting familiarity with what charges the car battery and how to care for your battery the right way.
Table of Contents
What Is The Car Battery Charging System?
Each of the Individual cells will have a positive electrode and a negative electrode floating in a pool of electrically charged and ionized electrolytes. If it’s a lead-acid battery, sulfuric acid will be one of its main components.
But that is just the battery and not the whole battery charging system, which has many different components than just the battery.
The charging system essentially allows you to keep the battery charged for as long as the cars’ engines are running. This is important since if the battery’s charge is not maintained constantly, it will run out so quickly you’ll end up motionless in the middle of a highway.
That is why they say never to keep the car’s headlights turned on when the engines are not running. It’s because the headlights will suck up a lot of charge from the battery. And in the absence of a proper charging system, the main component of which is the motors, the battery runs out almost instantly.
So what is the car battery charging system? It essentially consists of several parts. The main ones are the alternator, the motor, the wirings, the electronic control unit or the ECU, the regulator (the computer in modern cars).
The motor provides the mechanical energy for the alternator and drives it to help it generate electrical current. The electrical current needs proper wiring to be directed to the computer and the battery so that there is minimal loss of voltage/current and maximum input for the computer to compute and battery to recharge.
The computer does exactly what it sounds like it does. It constantly computes if the battery needs recharging, and if so, how much recharging. So in a way, it regulates the flow of electrical energy from the alternator to the battery and makes sure the battery is getting just enough, but not too much to cause malfunctions.
How Does The Alternator Work?
Think of the alternator as a mini generator built into your car as a part of its mechanics. It converts the engine’s mechanical energy to electrical energy for the battery?
Could we be more clear with easier-to-understand terms? Sure.
As the motors of your engine revolve, it creates energy. That is called mechanical energy. It’s nothing more than the mere revolution of the motors. Anything that moves is said to possess mechanical energy.
The basic principle is that it generates electricity as you move a magnet through a loop of wire. The amount of electrical energy generated depends on the number of loops of the wire, the conductance of the wire, and the magnet’s strength.
The alternator consists of a stator and a rotor. The stator is a stationary set of wire coils. The rotor is an electromagnet. As the electromagnet revolves inside the stator, it generates electricity in those coils of wire. This electricity makes its way to the computer and eventually to the battery to recharge it.
The alternator also consists of a rectifier, which converts the generated alternating current from the coils to the direct current needed for the battery. Alternating current (AC) is a bi-directional current; it changes its direction depending on how fast the rotor revolves inside the stator. Therefore, it needs to have a single direction to charge the battery. The rectifier does just that.
Here’s a video of the process.
Do Car Batteries Charge While Driving?
Driving ensures that the alternator gets all the mechanical energy it needs, so yes, Car batteries charge while driving. If they didn’t, your car would start malfunctioning within just 20 minutes of driving.
How To Charge A Car Battery
Step#1 - Getting ready to charge
Charging a car battery is easy. But you must come prepared. You must know that to charge a car battery; you must get it out first. Wear proper, insulating gloves because you can easily shock yourself if you’re a newbie. We don’t want that now, do we?
Make sure you have all the necessary tools to access the battery. Then, locate where the battery is sitting in your car (under the seat, in the trunk, or with the main engine) and get it out carefully and gently.
Step#2 - Get that battery charger
Plug in the positive terminal first and then the negative terminal (recall the principle). Set the charger to the slowest charging rate possible, and start it.
If it’s a reconditioning battery charger, you don’t have to worry about the timing. But if it’s a normal battery charger, set a timer according to the battery charger’s specifications, and don’t forget to check on the battery as soon as the timer goes off. Remember, this is very crucial, as even a tiny amount of overcharge can ruin your battery forever.
Step#3 - And that is it
When charged, remove the negative terminal first and then positive after turning the battery charger off.
Carefully place the battery back in the car and connect the positive first and negative later. Make sure all the headlights and lamps of the car are turned off unless you want to be shocked or something.
Frequently Asked Questions
How long do you need to drive a car to recharge a dead battery?
If the battery is completely dead, you might want to recondition it since it will not hold a charge no matter how long you keep driving the car.
However, if your battery is still new and healthy, 30-50 minutes of driving should be enough to charge the battery completely.
How long does it take to charge a car battery while driving?
The usual consensus is 30 minutes of driving to squirt enough charge into the battery. However, the number still depends on your battery’s overall health and condition and how long it has been sitting idle.
How to charge a car battery without a charger?
You can quickly charge a car battery without a charger using a Jumper cable available for $15 to $20.
Just make sure both the cars are turned off. Connect the positives of both the batteries. Same with the negatives. Start the car with good batteries and let it pour some charge into the bad batteries of the car requiring a charge. Let it run for over a minute or two, and then start the car with a bad battery. It should work.
Once the engines are roaring, 30 minutes of the drive should be enough to r-charge your batteries fully.
How do you know if your charging system is bad?
You know that the car’s charging system is bad because even after you have replaced the batteries, they do not hold the charge or are not fully charged no matter how long you drive. So, in this case, the only possible explanation is that the charging system is bad.
What causes the charging system to fail?
It’s usually a broken alternator belt or one that is worn out so much it keeps on slipping. It also depends on the quality of the belt because it needs to spin the alternator fast enough to generate the proper voltage.
How do I check my charging system?
You can easily check your battery’s charging system by using a car battery tester. Just connect the terminals to all the right places. It doesn’t depend if the battery is inside or outside the car since many battery testers can function both ways.
The battery tester should give you pretty solid results about the health of your battery and the charging system.
What will happen if the charging system fails?
You will end up stuck in the middle of the road, asking strangers to jump-start your car.
Do car batteries charge while the engine is idling?
Yes, the batteries will charge as long as the motors are running.
Are Fast Chargers Worth It?
Yes, they are if you want to save time, have some extra cash to spare, and need to get things quickly.
Conclusion
There are so many things when it comes to charging a car battery. Although we might not have covered everything in detail, we’re pretty confident we have told you enough to ensure you are confident enough when looking and analyzing your battery next time.
James is an engineer and a professional blogger. He has gained extensive experience over the years, handling all types of power projects. He loves to share his experiences with all things related to batteries, generators, and other power-related topics.
