How Do Electric Cars Work? An In-Depth Guide

Electric cars are powered by storing energy from the electrical grid in batteries, then using that energy to drive electric motors that make the car go. Electric vehicles use energy stored in batteries to power electric motors. They make use of the relationship between electricity and magnetism: When an electric current flows through a wire, it creates a magnetic field, and vice versa. An electric motor works by running current through a coil of wire to spin magnets, and a generator — like the alternator in a traditional car — generates electricity by spinning magnets inside a coil. This is why EVs can recapture energy to charge their batteries.

Of course, the motors can't generate enough electricity to completely recharge the system, so electric cars need to be charged up by another method. This means plugging them in and charging the batteries with energy from the electrical grid.

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Comparison with conventional fuel-powered vehicles

An internal combustion engine, or ICE, burns some type of combustible fuel (usually gasoline, but diesel, ethanol and other fuels are used, too) to generate the energy needed to move a vehicle. Beyond the whole "intentional fire" thing, there are some very important differences between using combustion and electricity for power.

  • Gasoline, the most common ICE fuel, has a much higher energy density than current EV batteries. That means a battery pack needs to be much larger and heavier than a gas tank to provide an equivalent amount of energy. But ...
  • Internal combustion engines are far less efficient than electric motors. The majority of the energy they generate burning fuel is lost as waste heat. In fact, only about a quarter of the energy stored in the gasoline winds up being used to move the vehicle. Electric cars, by comparison, are about 90% efficient.
  • An internal combustion engine can't recapture energy — you can't un-burn gas. But electric motors can also act as generators, meaning that they can add energy back into the batteries while slowing down the vehicle. That's part of what makes them so efficient. It's also why hybrid cars offer big efficiency gains since they can recapture some of the energy the gas engine produces as electricity.
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Components of an electric car motor

Electric motors are relatively simple mechanically since they don't require multiple moving parts. When current passes through a wire, it creates a magnetic field that exerts a force. If you've ever played with magnets, you know that the like poles repel each other while opposite poles attract each other. If you were to put a magnet inside an electric field, it would align itself with the field and then stop moving when it reached equilibrium. But if you keep the field switching back and forth, you can keep the magnet rotating by preventing it from ever reaching equilibrium. Switch the field faster than the magnet is spinning, and it'll spin faster to catch up, giving you acceleration.

In practice, electric motors are a bit more complex than that explanation suggests, but both direct current (DC) and alternating current (AC) motors use the same trick of rapidly switching the polarity of an electromagnetic field to generate motion.

So the opportunities for direct mechanical wear in electric motors are limited, and there's no combustion and no exhaust gases. It also means the power an electric motor can exert is determined by the strength of the magnetic field (which is determined by the amplitude of the current), not its rotational speed. Gasoline engines, conversely, need to expend energy to get themselves up to a minimum rotational speed before they can generate full power.

Because of the way electric motors operate, there are certain advantages to using an alternating current motor. AC motors can produce more power and operate more consistently when exposed to vibrations and other adverse conditions common when driving. They're also lighter, but they're more costly to produce.

Batteries

By far the most common type of battery currently used in electric cars is lithium ion (Li-ion). Lithium-ion batteries use an alloy of lithium and other metals in a liquid or polymer electrolyte solution to store charge.

Some older EVs used nickel-metal hydride (NiMH) batteries, but these batteries, while inexpensive to make, are heavier, less capable of discharging energy quickly, and more prone to damage from overcharging and to losing charge capacity.

In an electric car, lithium-ion batteries have lots of advantages. Saving weight is one, and easier, faster charging is another. Being able to discharge energy more quickly also means they can provide stronger acceleration.

Currently, a number of manufacturers and researchers are working on solid-state batteries, which still use lithium but don't require a liquid electrolyte solution. They promise significant weight savings, better energy density, faster charging, and less risk of fire due to damage. We won't really know how they perform until they're available in cars, which won't be for several years. At the time of writing, Nissan has committed to the fastest timeline, promising solid-state batteries in 2028.

Kilowatt-hours

Battery capacity is measured in kilowatt-hours, or kWh. This is very different from the way gasoline is measured, in gallons, because it doesn't have anything to do with weight or volume, but with how much actual energy is available. Usually, kWh is used as a measure of work. You see it most commonly on your utility bill, where it indicates how much power you used.

For example, a 300-watt space heater would need to run for just over three hours to use 1 kWh, while a 60-watt lightbulb would need to run for more than 16 hours. The average American household uses about 30 kWh a day.

The efficiency of electric cars is best measured as the number of kWh it takes to travel 100 miles, or kWh/100 miles. Just like on a gas car, more "fuel" doesn't always mean more range; efficiency plays a major role as well.

It's important to note that charging speeds use kilowatts, not kWh. A watt measures the rate at which energy flows; a kWh is a way to measure how much energy has flowed.

Voltage: 400 volts vs. 800 volts

Different electric car platforms are capable of handling different voltages. By increasing the voltage, you can increase the power (wattage) without increasing the amount of current (amperage). This means less heat, less need for cooling, lighter-weight components and more efficiency. One of the most important advantages of EVs with 800-volt architecture is faster charging … assuming you can find a powerful enough charging station.

For the most part you'll see 400-volt or 800-volt cars, although there are a few outliers. The Lucid Air uses suspiciously specific 924-volt architecture. Some vehicles, like the Hummer EV, use 400 volts for driving and 800 volts for charging. Some have variable limits, like the Porsche Taycan, which can temporarily charge at up to 1,000 volts.

Ultimately, the higher voltage systems offer weight savings and improved performance but come with a higher price tag.

Power inverter

Batteries require direct current (DC) to charge, and they release stored energy as direct current. But the power that comes from your wall socket for Level 1 or Level 2 charging is alternating current (AC). The motors in electric cars run on alternating current (and recapture energy as alternating current) since alternating current lets them provide more torque and more consistent operation regardless of conditions.

Power inverters convert DC to AC and vice versa — although they do much more than that. That means they're a necessary component for driving your electric car and for charging it at home. They convert energy coming from the battery to a form that's usable by the electric motors, and they convert energy recaptured by the motors, or energy coming from a Level 1 or Level 2 charging station, into a form that's usable by the battery.

Inverters are also capable of adjusting the frequency and amplitude of their output, which allows them to control the power and speed of an electric car's motors. Alternating current comes in pulses, and when the inverter converts DC to AC it can control the frequency and amplitude (think, strength) of the pulses it outputs. Increasing or decreasing the frequency of the pulses increases or decreases the speed at which the motor turns, and increasing or decreasing the amplitude of the pulses increases or decreases the torque the motor generates.

Benefits and limitations of power inverters in electric cars

Power inverters allow electric cars to charge from a household outlet or Level 2 charging station. They increase the range and efficiency of electric cars by allowing for the use of AC motors and allowing the motors to charge the battery.

Power inverters also add weight and cost to electric cars, and they are another potential point of failure should anything go wrong. They're also a major chokepoint in the system: Because all current flowing between the charger, motors and battery must go through the inverter, the limits of the inverter are also the limits of the car's performance for both acceleration and charge time. That's why Level 3 fast-charging stations provide direct current, bypassing the inverter and allowing much faster charge times.

Charging port

The charging port is where the plug from a charging station can be connected to an EV. What type of port you have will determine what kind of charging station you can connect to or what kind of adapter you'll need to charge. Fortunately, you only really need to worry about one choice: Are you getting a Tesla, or literally anything else?

In the United States, you're only likely to come across three types of charging ports on an electric vehicle: CCS, Tesla and CHAdeMO. CHAdeMO only appears in the U.S. on the Nissan Leaf, and it's headed the way of the dodo (at least in this country), so we won't spend time on it. Tesla, unsurprisingly, is used by all Tesla models. It's a single plug that can handle Level 1, 2 and 3 charging, which certainly makes life easy.

All other EVs being sold in the U.S. have CCS, or combined charging system, ports. This combines a Level 1 and 2 charging port, poetically named the SAE J1772 connector, with two high-speed charging pins (hence "combined"). Basically, if you're charging at home, you'll just plug in to part of your port. If you're using a public fast charger, you'll have a chunkier plug that connects to both parts of the combined port.

While CCS charging stations are currently capable of charging at a speed of 350 kW, your car may not be capable of accepting charge that quickly. With a little research, you can find out how fast your vehicle can charge when plugged into an appropriate DC fast charger.

Controller

The controller is the name for the electronics package that connects the batteries and motor or motors. When you step on the gas, apply the brakes, or switch into reverse, it's the controller that feeds current to the motor for acceleration, reverses the flow for regeneration, and even reverses the motor's direction of spin so you can back up. When using AC motors, the controller includes the car's inverter.

Charging an electric car

Now that you've got a better grasp of an EV's mechanical bits, let's talk about charging, from the various types of chargers (both home and public) to how long you can expect charging to take.

Types of charging stations

There are only three types of charging stations, but in practice, things aren't really that straightforward. The three types are Level 1 (110-120 volt), Level 2 (220-240 volt) and Level 3, or DC fast charging. That last one is where things get tricky, as fast-charging stations can technically have a voltage cap of anywhere between 480 volts and 1,000 volts, meaning a DC fast charger may be capable of delivering up to 360 kW of power, but some Level 3 stations may only deliver a peak of 50 kW.

If your EV can accommodate very fast charging, you'll need to make sure you find a Level 3 fast charger that's actually outputting enough power to take advantage. Many charging networks will let you check speed ranges of charging stations through their apps, but many will also charge extra for high-speed charging.

Tesla remains an outlier. While Teslas can use Level 1 and 2 chargers, they use Tesla Superchargers for fast charging. These charging stations operate at 480 volts but provide different amounts of power depending on the version. Version 1 and 2 Superchargers provide 150 kW, while version 3 provides up to 250 kW. Tesla claims a forthcoming version 4 will increase charging speed even more.

Home charging options

Home charging is generally done with a Level 2 charging station, a special piece of equipment that should be installed by an electrician. Level 2 charging stations require a 240-volt circuit, so if your home already has special plugs for an electric dryer, heater or water heater, you shouldn't have any issues. If your house doesn't have any 240-volt outlets, you'll need to consult an electrician to see if one can be installed.

Level 2 charging stations can be installed indoors or outdoors, so whether you park in a garage or in a driveway or carport, you should still be able to charge your EV. While not remotely as fast as a public DC fast charger, a Level 2 charging station should be able to refill the battery on most electric cars if left plugged in overnight.

It is possible to use a Level 1 charger, which only requires a standard 120-volt outlet. Many EVs come with adapters that let them plug in to a typical outlet to charge. Just be aware that charging speeds are painfully slow with a Level 1 charger — even if you plug in overnight you may not add more than 30 miles of range.

Public charging options

When charging in public, you'll usually find Level 2 charging stations and Level 3 DC fast chargers. While there are a handful of CHAdeMO stations, most public fast chargers will use CCS (see the "Charging port" section above). If you own a Tesla, you'll have access to the Tesla Supercharger network. Tesla has also recently opened its charging stations to other EVs.

You may live somewhere with access to free or municipal charging stations, which will almost always be slower Level 2 stations. But for the most part you'll be charging at public stations owned and operated by a charging network. These stations allow you to pay as you go, but you can also sign up directly with one or several networks to make paying easier and maybe even save a bit of money on charging.

Remember, if you want to take full advantage of your car's max charging speed, you'll need to find a public DC fast-charging station with an output that matches or exceeds your car's spec.

Charging time

If you're charging with a Level 1 charger, you can expect to add 3-5 miles of range per hour, and with a Level 2 charger you can expect to add 25-30 miles of range per hour. These speeds are pretty consistent because the wattage of these charging stations and the capacity of the car's onboard power inverter are predictable.

For Level 3 fast charging, things are a bit more complicated. Most manufacturers will advertise a predicted maximum charging speed, usually from zero to 80% of max charge. These predictions are based on a Level 3 charging station with sufficient power output operating in ideal conditions, and you may not match them in real life.

Theoretically, you should be able to calculate your total charge time based on just the power output of the charging station and the total battery capacity of your vehicle. But things aren't that simple.

When you first plug in, there's a conditioning time required before your battery can accept max charge speed. Max charge speed also only generally occurs for a brief period of time, which can vary depending on conditions and charge level. Charging speed also decreases as the battery passes 80% of maximum charge. Moreover, even a charger that claims a specific power output may not always operate at that output, and you won't know until you're plugged in. Level 3 charging time, in short, is relatively unpredictable.

Advantages and disadvantages of electric cars

How are we doing? Hopefully you're a lot closer to understanding how electric cars work than you were before we started. Now that we've covered the major points, let's go back to the beginning. We mentioned that there are plenty of reasons why EVs are the next big thing, but there are some drawbacks too. Here's a full analysis.

Environmental benefits

Electric cars can bring significant benefits to local air quality if adopted at scale, and they also significantly reduce greenhouse gas emissions compared to gasoline-powered vehicles. The former may seem obvious, as EVs have no tailpipe emissions and produce no particulate or gaseous exhaust. That means fewer pollutants that have been linked to cancer, respiratory and cardiac issues, developmental delays, cognitive impairment and a plethora of other health concerns.

The latter — greenhouse-gas reduction compared to gasoline vehicles — is more nuanced. Local pollution from mining the materials needed to produce batteries is an issue, especially in countries with lax regulations. It's worth noting that these materials are in high demand even without considering the electric vehicle market, but as EV production scales up, this concern will only intensify.

It's also true that EV production creates more greenhouse gases than ICE vehicle production, in particular from battery manufacturing. EVs can potentially create up to 80% more carbon emissions during production, but once the vehicles hit the road it takes an average of about 15,000 miles for an ICE vehicle to surpass an EV in net emissions. The U.S. Department of Energy performed a study in 2022 and found that, on average, an EV in the United States creates 3,932 pounds of carbon dioxide equivalent per year. Gasoline vehicles, by comparison, create 11,435 pounds per year. Even when using electricity derived from coal plants, an EV creates fewer net carbon emissions because it uses energy so much more efficiently than a gasoline vehicle. Of course, electric cars can be charged using clean energy like solar, wind, hydro and geothermal power, meaning they can run as cleanly as the grid that charges them. That's an advantage an ICE vehicle can never have.

Cost comparison between charging an electric car and refueling a conventional vehicle

Gas and electricity prices both fluctuate, and DC fast chargers can have higher charging costs, especially during peak use hours. But the cost per mile of fueling an EV will almost always be less than the cost per mile of fueling an ICE vehicle. This is especially true if you can charge at home, as residential electricity rates are significantly lower than what you'll pay to use a public charging station.

If you live somewhere with access to very inexpensive gas and access to DC fast-charging stations, there may be some times where the cost to fuel per mile is greater using the Level 3 charger than it would be to buy gas. But while gas stays the same price all day, charging gets less expensive off peak hours, so you can save a bit by planning ahead of time when you'll charge up.

Ultimately, EV owners will save money compared to ICE vehicle owners when it comes to fuel. If you want to learn more, check out our article on the cost of charging an EV versus buying gas.

EV maintenance benefits

Electric cars are significantly less mechanically complex than ICE vehicles, although to varying degrees. Some EVs use simple transmissions, and most have other moving parts connecting the motors to the wheels. But the engines and transmissions of gasoline cars have thousands of moving parts, each of which can be a failure point, and as a result these cars require significantly more maintenance and upkeep to stay in good working order.

Electric motors also don't use oil the same way an ICE does, as you have probably surmised. Electric motors have bearings that may be greased, but grease doesn't degrade or require replacing like oil in a gasoline engine. Engine oil loses its lubricating ability relatively quickly, getting loaded up with contaminants even when an engine is operating perfectly. That's why oil filters need to be regularly replaced with engine oil.

Furthermore, with an electric car there are no timing belts/chains to replace, no spark plugs, no rings that can degrade or slip, no intake ports to clean, no exhaust pipes or mufflers to rust or perforate, no catalytic converters … the list goes on.

Indeed, the primary maintenance needs of electric cars are simply brakes and tires. Tires, in particular, can wear out faster on electric cars due to the extra weight of many EVs and their ability to apply immediate big torque on acceleration. Brakes, however, may last longer on EVs if regenerative braking is used heavily.

Battery packs do degrade over time, losing charge capacity, and they may eventually fail. But in most cases, this degradation shouldn't impact day-to-day driving for quite some time. Battery warranties are also commonly 100,000 miles and 10 years or more, generally longer than the warranties for gasoline engines.

If a battery pack does need replacing outside of warranty, the cost can range massively, from about $4,000 up to $20,000. Considering an average cost between the two extremes, and the savings on regular maintenance and repairs, an electric vehicle still costs less to maintain over its lifetime than a comparable gas vehicle.

Driving experience

Depending on how an electric vehicle is set up, it can feel more or less like a traditional ICE vehicle. The most noticeable difference when you get into an electric car will be the lack of noise and vibration from the powertrain. In fact, EVs are so quiet that they're legally required to have speakers that make an artificial noise at low speed so pedestrians have a chance to hear them coming.

Another key difference is the lack of gear changes. Electric motors can spin much more quickly than a gasoline engine, and they produce more consistent power regardless of the speed at which they're spinning. Electric motors also produce torque instantaneously from a stop, where a gasoline engine needs to rev up a bit to reach its peak torque output. The immediate torque and lack of shifts make for smoother driving and a feeling of instant acceleration.

The other major difference is regenerative braking. Most electric cars let you select how much or how little regenerative braking you'd like when you lift off the accelerator pedal. So if you'd prefer a more traditional feel, you can turn regenerative braking down so the vehicle will coast and only slow when you apply the brakes (when it will use a combination of regenerative and physical braking). But for the full EV experience, you can turn regenerative braking all the way up, which means the throttle becomes less an accelerator pedal and more a speed selector pedal.

This is called one-pedal driving, and it's not possible in every EV. Not all EVs have strong enough regenerative braking, and not all will be able to bring the vehicle to a full stop with regenerative braking. But in a vehicle where it's possible, the instant you lift off the pedal, the car will slow in accordance with how much you've lifted. So you use the pedal to select a constant speed, reducing pressure to maintain a slower speed and pushing down to maintain a higher speed — as opposed to a gas-powered car, where you would hold the pedal down to accelerate and then reduce pressure to maintain the speed you've reached.

Range limitations

Many people cite range anxiety as either a major concern in choosing an EV or a reason not to buy an EV at all. There are several reasons range anxiety is such a big problem for electric cars.

Gasoline cars are very flexible. Increasing or decreasing the size of the fuel tank to increase or decrease range doesn't have a large impact on vehicle weight or cost, and doesn't change how long it takes to refill by very much. Also, filling up even a large tank with gas only takes a few minutes.

In an EV, only so much can be done with aerodynamics and efficiency to add range; beyond that, the only solution is to add more battery cells. Not only is that a significant added cost, extra batteries also need a lot more space, and they add a lot of extra weight (which in turn hurts the vehicle's efficiency).

More batteries also mean more charging time, which is less of a problem if you have easy access to DC fast chargers, but that access is inconsistent nationally. Right now, the fastest-charging EVs can add a maximum of 15-20 miles per minute, significantly slower than refilling a gasoline car. And if you can't find a fast charger, or don't have a car capable of such high-speed charging, you might be stuck at a charger for a while to recharge enough to reach your destination.

Until there's more charging infrastructure, or new battery technology that can improve range and charge times, EVs will have limited appeal for people who need to drive long distances or who live in areas with few public charging options.

Charging infrastructure

Charging infrastructure is one of the biggest hurdles for EV adoption. At issue is both the number of charging stations available and their reliability. In our own extensive real-world testing of electric cars, we've experienced plenty of issues with charging stations operating at lower speeds than advertised, or not working at all. And with limited numbers, there can sometimes be wait times for charging stations in high-traffic areas. However, the number of charging stations is growing rapidly, and the bipartisan infrastructure law has allocated funds to build an additional 500,000 charging stations.

But if you have, or can install, a charging station where you live, infrastructure becomes much less of an issue for day-to-day life. If you can plug in at night and your commute doesn't involve significant distances every day, you'll basically wake up every morning with enough range to get through your day and get home again. As commuter cars, EVs have a massive edge over ICE vehicles in terms of convenience.

Edmunds says

Whew! So that's how electric cars work and why you may or may not want to consider buying one. If you're interested in making the switch, check out our list of the best electric cars. Or, if you've got severe range anxiety, head over to our real-world range test to see which electric cars can actually go the distance.

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