Is Your Alternator Enough?

Most people just rely on their vehicle’s alternator to keep the battery charged, but is it enough? Before we answer that question, let’s talk a little about what an alternator is and what it does.


Many people don’t think about their alternator until it goes out, but it has a pretty important job sitting under the hood. The alternator is a small electrical generator that provides electricity to your car by converting mechanical energy to electrical energy. The alternator provides current to the spark plugs, lights, A/C, sound system, and more. For a car part that is about the size of a loaf of bread, the alternator does a lot of work.

What Does the Battery Do?

So, at this point, you may be thinking, I thought the battery did all of that! Actually, the battery really only has two jobs: powering electronics when the vehicle isn’t running and starting the engine. Once the engine starts, the alternator takes over and supplies the electricity that your vehicle needs.

If you had to rely on your battery to run your car, you would only get a few miles down the road. Anyone that has had an alternator go out on them knows the feeling as you see your lights begin to dim and you lose power to your engine, with it finally stalling out. It doesn’t take long once the alternator quits for the rest of the vehicle to also shut down.

If the alternator is working correctly, it not only supplies power to the vehicle, it also sends voltage to the battery to charge it. Most batteries have a voltage of around 12 volts, whereas the alternator’s output is between 13 and 15 volts. 

How Does an Alternator Work?

Earlier we said the alternator was a small electrical generator, but what does that mean? The alternator is pretty simple in its construction: a voltage regulator, a stator, a rotor, and a diode. That’s it. When the engine is running, a belt turns a pulley on the alternator, causing the rotor to quickly spin inside the alternator. The rotor is made up of a magnet or group of magnets and is inside a stator, which is a nest of copper wires.

The magnets spinning inside the copper wire creates electricity through electromagnetism. The electricity that is created is sent to the diode which changes the current from AC to DC, the current used by the car battery and the rest of the vehicle.

After this step, the voltage regulator steps in. The voltage regulator shuts off the electrical flow to the battery if the voltage gets too high. If the battery is overcharged, it can burn out. As the battery voltage lowers, the regulator allows the current to flow back to the battery, helping it maintain a useful charge.


An alternator cannot do everything a charger can. For starters, an alternator can charge a battery with a low charge, but it cannot charge a dead battery. As we said above, the battery’s job is to start the engine and then work as an electrical load balancer. The alternator runs the electrical system of the vehicle from the engine to the wiper blades to the seat warmer, while keeping the battery topped off.

Most vehicle batteries are “full” at 12 volts, but if the voltage drops to just under 10 volts (less than a 20% loss), the alternator won’t be able to keep up on charging it and the battery’s cells can be damaged. If the alternator can’t charge a discharged battery, it definitely can’t bring a dead battery back to life. 

Some people think that they can just drive around and recharge their battery, but this isn’t the case. In most instances, it will only provide a surface charge to the battery, which is pretty much worthless. In worst case scenarios, the alternator can be damaged or even completely destroyed. This is why it is important to invest in a CTEK Smart Charger.

If you have to constantly charge the battery, either your alternator or your battery is about to die. It’s important that you fix the problem before you are stuck with a car that won’t start or run.


When you use a CTEK smart charger to charge your vehicle’s battery, you not only charge the battery, but the charger will also test the battery and rehab it if it is damaged. When your battery goes through the desulphation process with a CTEK charger, it can extend the life of your battery 2-3 times. Most batteries last 3-5 years, so you can see what a benefit this can be. 

When the battery is attached to a CTEK smart charger, the battery will be run through a 4 to 8 step charging process. The charger will monitor the battery throughout the process, making sure the right step is being used: desulphate, revive, charge, condition, and maintain. By having a healthy battery in your vehicle, you will save yourself stress from having a dead battery, avoid the cost of buying a battery and having your vehicle towed, and keeping more batteries out of the landfills. 

A CTEK smart charger is designed and engineered to allow you to set and forget it for months without harming the battery. You don’t have to worry about connecting it wrong or being injured by a spark. The smart charger will tell you if it’s connected wrong and will protect your battery and the Smart Charger won’t spark no matter what. All of the CTEK products are easy and safe to use for every level of expertise.

Contact us today to learn more about our line of smart chargers and find out which one is best for you. We look forward to doing our part to keep your vehicle running well.