Do Electric Cars Have Alternators? Can They Charge EVs?

Alternators are an integral part of a car – they keep the 12-volt battery charged and also power the starter, lights, locks, and more. This makes them a regular fixture in most vehicles. Are electric cars included?

Electric cars don’t have alternators. Electric vehicles are designed so that they don’t need to convert mechanical energy to electrical energy to keep batteries charged. Alternators are most useful in fossil-fuel vehicles. Installing one in an electric car is possible but unnecessary.

In the rest of this article, I’ll cover all you need to know about alternators. You’ll find out why they’re not a common fixture in electric cars, whether they’re used in hybrid cars, and whether Teslas have alternators.

What Is an Alternator?

An alternator is a type of generator responsible for producing the electricity stored in a car battery. It keeps the battery charged and powers the core components of the car. 

It’s called an alternator because it converts alternating current generated by the vehicle engine to direct current for the battery and your car’s electrical components to use. Your battery will run out if the alternator isn’t working. In that scenario, the car will stop working.

In the past, cars featured DC generators. They were swapped out because alternators were lighter, more reliable, and could deliver more power overall. 

Green-Turbo

I also researched and discussed if Can Electric Cars Have Turbo? Feel free to check it out!

Alternators are positioned in front of engines and are connected to the vehicle’s crankshaft via a drive belt. The belt rotates parts of the alternator as the engine runs to generate electricity and keep the battery charged.

They are extremely durable and can last more than ten years. However, the drive belts connecting them to the engine can wear out quickly. 

When the alternator gets faulty, it won’t generate enough electricity for the battery to meet the car’s electricity demands. The first sign of a problem is the dashboard warning light. If you ignore that, the vehicle will stop working after a while.

Electric cars don’t have alternators because they don’t need them. Combustion engines need alternators to keep your 12V batteries charged and power critical components in the vehicle.
Photo: @amynapaloha via Twenty20

Why Don’t Electric Cars Have Alternators?

Since alternators are so important, you may be wondering why they aren’t available on electric cars.

Electric cars don’t have alternators because they don’t have an engine to generate alternating current. They feature DC to DC converters which are generally better than alternators.

As we mentioned above, the energy that powers an alternator comes from the mechanical energy created by a fossil fuel engine during combustion. Electric vehicles were developed to stop fossil fuel burning, so they don’t come with such engines. Instead, they feature a rechargeable battery that powers an electric motor.

These vehicles have DC to DC converters to change the direct current generated from one voltage to another. They are better than alternators in many ways. 

First, they’re compact, so they won’t add to the weight of the vehicle. They’re generally more efficient with reduced lost energy. You also don’t have to worry about maintenance because they don’t come with any moving parts.

 AlternatorDC/DC Converter
SizeBulkyCompact
EfficiencyLow efficiencyHigher efficiency
Moving PartsBelts, bearings, and pulleyNone
LifespanUp to 10 yearsUp to 30 years
Table showing the differences between alternators and DC/DC converters

Why Can’t an Alternator Charge an Electric Car?

An alternator can’t charge an electric car because it needs power from the motor to work. Such a setup in an electric car will lead to a net loss of energy.

You should keep in mind that an alternator takes more power to run than it produces because it’s not a perpetual motion machine.

If you’d like to find out if Electric Cars Have Catalytic Converters, check this article that I wrote. The answer is abvious but I also discussed hybrids.

Can You Put an Alternator on an Electric Car?

In theory, you can put an alternator on an electric car. However, doing so is unnecessary and may adversely affect your car parts. It’s also unlikely to generate enough electricity to power the car.

To put an alternator on an electric car, you have to use the car battery to spin the vehicle motor and then spin the alternator to generate electricity. You’d end up using some electricity to make more electricity, but there’d be a lot of conversion losses in the form of vibration, heat, and noise.

You’ll also only end up generating electricity smaller than the one you used in powering the alternator.

You may also fail to generate the right voltage required to power the car’s components. In a fossil fuel car, you only need to generate enough power to charge a 12V system. For an electric car, the battery pack is generally over 300VDC. So, a DC/DC converter is always the more efficient solution.

Do Teslas Have an Alternator?

Teslas don’t have alternators. They’re designed like other electric vehicles and work with DC to DC converters. The converter transforms the high voltage current from the main battery pack to a lower voltage enough to charge the 12V battery powering elements like the lights and radio.

As discussed above, you can’t install an alternator in a Tesla either because it won’t generate enough electricity to move the car.

Do Hybrid Cars Have Alternators?

Hybrid cars don’t have alternators. They have multiple motor/generators (M/Gs) that are designed to produce the voltage required to power the car. The M/Gs and a DC/DC converter are linked together in a specialized system known as a planetary gear set. 

Hybrids come with two batteries: the main battery pack and the auxiliary 12 volts unit. The main battery packs have a voltage of up to 288 volts. In some vehicles, the voltage can be transformed to as high as 500 volts with the help of a voltage booster.

The M/Gs lower the power from the battery pack to the 12 volts needed to power the auxiliary battery, which powers the electronic accessories in your vehicles. It’s not uncommon to find people referring to M/Gs as converters because they ensure the auxiliary battery and other such items can be charged safely without damage.

The M/Gs in some vehicles look like an alternator in appearance. You can find these in some General Motor models. However, they work nothing like alternators – they don’t have any spinning parts as they quietly convert voltage.

So, if you get a signal on your dashboard saying that your 12V auxiliary battery isn’t charged or is getting discharged, you shouldn’t go looking for an alternator. Look at your planetary gearset, especially the DC/DC converter. You’re likely to get a warning if a converter is malfunctioning.

In such cases, you should look at the wire first. If you’re not car savvy, call in a professional to check out the cause of the warning. In some cases, they may be false positives.

Can an Alternator Run an Electric Motor?

An alternator cannot run an electric motor. The alternator system needs an energy source to work. It can’t power a motor without energy coming from either a battery or a combustion engine.

Remember, if you power the alternator with a battery, it’ll generate less power than you’ve got in the battery. If you don’t intend to use a combustion engine and fossil fuel to power your alternator, it’s best to install a DC/DC unit to run your electric motor.

Do Teslas Charge While Driving?

Teslas don’t charge while driving unless you activate the regenerative braking function. The technology saves some of the energy used in breaking to recharge the car’s batteries.

Braking leads to some energy wastage. Regenerative braking ensures that some of that energy can be converted and reused for charging the vehicle. 

This feature is common in many modern cars, both conventional and electric. In fossil fuel-burning cars, the energy saved is used to power various systems in the car, reducing the workload on the engine while saving fuel. In such cars, the system works in the background, and a driver will rarely notice.

In Teslas and other electric and hybrid vehicles, regenerative braking is a lot more prominent. In these models, the brake regeneration will help charge the main battery pack as the car moves.

How the Regenerative Braking Process Works

The electric motor you’d find in a Tesla operates in two directions. One direction is responsible for driving the wheels and moving the car, while the other is responsible for recharging the battery.

As soon as you move your foot off the accelerator pedal and onto the brake, the motor will change directions to start delivering energy back into the battery.

As soon as the mechanism is engaged, you can feel the car slowing down. The sensation felt in regenerative braking while in a Tesla is slightly less pronounced compared to what you’d feel in other electric vehicles. Different manufacturers have different interpretations of how much regenerative braking is allowed when it’s activated. 

You can also tailor regenerative braking according to your own preferences. 

So, you can set it to the maximum setting if you want the car to harvest the highest possible percentage of lost energy. You’d feel the sensation strongest in that setting. You can also keep the setting in the middle for a more balanced approach. If you have a car charging source at your destination, you can turn off the mechanism entirely.

If regenerative braking is engaged, you can see the car brake lights come on as it starts to slow down. You may see the lights even when you’re not touching the brake pedal if you’re using the cruise control system with the regenerative braking activated. The car will monitor the one in front with built-in sensors, activating the braking system when necessary to keep pace with its speed.

Pro Tip:

If you’re on cruise control, you’ll see the speed that you’re going at in the little blue circle. On the left you’ll see the speed that you’re going at and on the right you’ll see the speed limit for the street that you’re on. If you tap max speed on the street that you’re on the car will automatically set the cruise control speed to that exact limit. If you speed up and tap on the speed that your currently driving at, the car will automatically set the cruise control speed to that speed.

The one major downside to regenerative braking is the brake pad feel, which can take some time for you to get used to it. If you find it a bit frustrating, you can turn it off and charge your Tesla using standard charging systems.

Check out this YouTube video for more information on regenerative braking:

Where To Charge Your Tesla

You can charge your Tesla (and other EVs) at home, at work, or in other designated charging stations along your route. Just as many workplaces are now making provisions for EV charging stations, service providers are also installing some to attract more clients.

For example, service stations now offer EV charging docks. Supermarkets and retail parks are also adding them to give the car owners a reason to visit and stay long enough to shop.

This arrangement is a win-win for all parties. The customers get to recharge their vehicles or top-up, while the supermarkets get more money from extra purchases the customers are likely to make the longer they’re inside the retailer.

You can also check car dealerships as some of them now allow members of the public to use their charging stations. Hotels, restaurants, beauty parlors, etc., are all places you can charge your Tesla.

Some of them will allow you to charge for free as long as you’re a paying customer. If that arrangement isn’t available (or you’re not a customer), you can consider going to a charging station where you have to pay to charge your vehicle.

The bottom line is that EV car charging stations are almost everywhere now. Your car will most likely never run out of juice with a little bit of planning and awareness. You can also choose to install a charger at home – that said, keep in mind that it will cost between $600 and $1000 for a basic unit.

How Long Will an Electric Car Battery Last on One Charge?

An electric car battery will last between 250 and 400 miles on one charge, depending on the size of the battery installed. A top-of-the-line EV like the Tesla Model S can last more than 400 miles on a single charge.

However, you should keep in mind that the numbers are rarely exact. There are many factors that will come into play to influence how long your car battery will last, so you need to always be proactive to ensure your car battery won’t die in the worst possible moment. 

Factors that can affect the battery lifetime include your driving approach, the roads you frequent (highway or dirt roads), components you use in the car, etc.

Are Alternators Better Than DC/DC Converters?

Alternators aren’t better than DC/DC converters. If you look at their functions separately, an alternator is generally less efficient. However, it works well in combustion engine vehicles.

DC/DC converters are unbeatable in electric or hybrid vehicles. However, engineering DIY experts can experiment with both options.

Final Thoughts

If your electric vehicle develops battery or charging issues, take it to a repair shop for a professional diagnosis. In many cases, the problem typically lies elsewhere instead of in the DC/DC alternator equivalent.


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Erwin Meyer

I'm passionate about Tesla and electric vehicles. I was a TSLA shareholder before the hype and still am. I also believe in Tesla’s speedy mission to accelerate the world to a sustainable future.