The Science of Range Understanding Factors that Impact EV Driving Distance

What You Need to Know about EV Range and What Affects It

• An electric vehicles range refers to the number of miles an EV can travel on a fully charged battery, or a single charge.
• While an automaker may advertiseand the EPA will confirma certain range for a vehicle, that number represents an ideal or theoretical distance it will travel on a charge. Much like with a gasoline-powered car, real-world factors can lower what is achieved compared to the EPA estimate.
• Everything from tires to weather to driving style may lower an EVs rangeor possibly extend it.

If you own a gas vehicle, youre familiar with the routine: When the gas gauge drops, you pull over at a gas station, fill up, and hit the road. Its an easy process that takes a few minutes, and other than the hit on your wallet, its relatively painless. Electric vehicles arent quite so simple in this area. When an EVs batteries are depleted, you need to find a charging station, plug in, and wait. How long you can travel between charging sessions varies from vehicle to vehicle, but while range isnt everything, its certainly a number worth digging into.

What Is Range?

Range refers to the number of miles an EV can travel on a fully charged battery. People often say single charge, which means the same thing. In the early days of electric vehicles, low range estimates were quite common, as battery and efficiency technologies were still taking shape. Today, there are still several EVs on sale with range estimates of around 200 miles or less, and while some are on the more affordable end of the price spectrum, many are expensive. The break down in price seems to happen along the lines of premium versus everyday brandsjust as it does for gas-powered vehicles.

When you see an advertisement for a new EV, you'll likely also see notes from the Environmental Protection Agency (EPA), which estimate the model's miles of range. The agency tests vehicles in a variety of situations that include highway driving and other situations so that car shoppers can make an educated decision. Rather than give a fuel economy rating, the agency assigns a range number that it feels accurately and fairly reflects an EV's capabilities.

What Impacts EV Range?

Automakers are well aware of the fact that many people are skeptical of EVs because of range concerns (also called range anxiety) and charging times. So, while it will soon be possible to buy nearly 10,000-pound giant electric pickup trucks, most electric vehicles are designed with aerodynamics and efficiency in mind.

Tires Can Help Reach Long Range

Your tires impact quite a bit more than ride quality and handling, especially for EVs, where they can have a noticeable influence on range. Specialty tires and tires that are over- or under-inflated can create more rolling resistance, which negatively affects range. Tire makers have worked with vehicle manufacturers to develop tires specifically for EVs. Low rolling resistance tires and other efficiency-focused tires help improve range but may negatively impact handling and ride quality because of reinforced sidewalls and special tread patterns.

Weather Matters

When the weather changes and temperatures drop or climb significantly, electric vehicles can lose as much as 25% of their advertised range. In gas-powered vehicles, the engine generates heat, much of which is excess and can be used to heat the passenger compartment.

Electric vehicles, on the other hand, do not have that benefit and have to use electricity for everything, and powering climate controls can put a big strain on the battery. Automakers are working to lessen weathers impact on EV range with heat harvesting technologies and more, but there is still progress to be made.

Your Driving Style Is Important

One of the most important factors in EV range has nothing to do with the vehicle or how it was made. Its you. Your driving style has an outsized impact on EV range and can be the tipping point between reaching a vehicles advertised range numbers or falling well short of the target. Quick acceleration is a big selling point for new EVs, as many can meet or beat the 0-60 mph times of exotic supercars, but taking advantage of that acceleration can greatly reduce the range in a negative direction. Driving smoothly is the key to achieving the best range.

What Affects Electric Car Range and How To Maximize It

For drivers of electric vehicles (EVs), range is a primary focus. As EVs become more popular and charging stations become more widespread, range concerns continue to dwindle. But those looking to switch to an EV still want to be confident that their vehicles range can get them where they want to go and back. Drivers want to know not just How far can I go? but also How can I go farther?

Understanding Electric Car Range

EV range, put simply, is the distance a car can travel on a single charge. EV efficiency is reported in miles per gallon of gasoline equivalent (MPGe). These estimates, provided by the Environmental Protection Agency, are just that: estimates. According to the agencys website, your mileage WILL vary. And while the MPGe numbers can be helpful, often the more important number for drivers is simply the estimated single-charge range.

According to a J. D. Power report on EV ownership, range is the most important factor in customer satisfaction. In fact, the report states that, accuracy of the stated battery range and actual battery range experienced by the owner account for about 20% of owners overall satisfaction. Those estimates matter. Its all about peace of mind for the driver: You want to know exactly how far you can go between charges.

4 Primary Range Factors

There are a number of factors that affect EV range. Fortunately, some can be improved by drivers:

1. ) Speed

Unlike internal combustion engine (ICE) vehicles, EVs fare much better in city driving. Their ability to regeneratively brake helps maintain a charge while operating in stop-and-go traffic. However, according to Car and Driver, no EV has yet lived up to its estimated range at highway speeds. The Audi e-tron performed best at 75 miles per hour, achieving 93% of its Environmental Protection Agency estimated range. If you are consistently logging highway miles, it is important to factor in your EVs ability to maintain range at speed.

2.) Weather

Extreme temperatures can have a significant effect on EV range for two reasons. First, an EV batterys ability to hold its charge is negatively affected by very low temperatures. Both efficiency and the ability to rapidly charge can be affected by freezing temps. Additionally, operating your EV in hot or cold climates also means you will be operating your cabin climate controls. Keeping your vehicle warm or cool affects range, as it draws on the battery power.

3.) Charge Capacity

It sounds obvious, but EV range is also affected by how full you charge your battery. Automakers implement complex battery systems that limit maximum charge in order to prolong overall battery life. Essentially, your EV will not regularly be charged to 100% capacity. This becomes especially important to consider on a longer trip, since many rapid-charge stations can quickly bring an EV up to 80% in as little as 30 minutes.

4.) Battery Age

As a battery gets older, it loses some maximum charge potential. However, this should not deter potential drivers, as the rate of degradation is only about 2.3% per year, and with proper maintenance it can be even lower. And with a federally mandated eight-year, 100,000-mile battery warranty, you can reliably expect an EV to perform well for many years.

EV Range Compared to ICE Vehicles

It is important to keep in mind that traditional ICE vehicles are affected by the very same factors as EVs. And while some factors affect one or the other type of vehicle more, it should offer peace of mind to potential EV drivers that EV range concerns are not new.

For example, running the air-conditioning or operating in very low temps has a similar impact on ICE vehicles: The US Department of Energy (DOE) claims that at 20 degrees Fahrenheit, ICE vehicles can lose up to 24% of fuel economy on short trips. And as already stated, while EVs fare well in city driving, ICE vehicles experience significant hits to fuel economy in stop-and-go traffic. The most common difference that drivers will experience is access to charging or fuel. As EV charging stations become more widespread, range will continue to shift from a necessity to a luxury.

How To Maximize Electric Car Range

While some impacts on EV range are beyond a drivers control, there are many steps you can take to ensure maximum efficiency.

Vehicle Preconditioning

If you are driving in extremely cold or warm temperatures, it is an excellent idea to precondition your vehicle while it is still charging. While it is still plugged in, turn on either the A/C or the heat and allow the vehicle to get to a comfortable temperature. Many EVs even have a system to input a desired temperature and expected departure time to properly precondition the cabin. This allows your vehicle to efficiently maintain the cabin condition instead of altering it while using battery power alone.

Regenerative Braking

Take advantage of your EVs regenerative braking system. When you lift your foot off the accelerator in an EV, the electric motors operate as generators while slowing the vehicle. If you set your EV to its maximum regen setting, you will experience positive real-world range effects.

Routine Maintenance

Making sure your EV is operating properly will benefit your range. Maintenance for an EV is slightly different from maintenance for traditional ICE vehicles. Every 7,500 miles, you should be routinely checking components for wear, rotating tires and checking fluids. Like with any vehicle, making sure tires are properly inflated and drivetrain components are functioning smoothly will help efficiency. Additionally, as your battery ages, refurbishing dead cells to maintain maximum capacity will help keep your range closer to its original number.

Matching Your Vehicle to Your Needs

Before purchasing an EV, take into account the various factors that affect range. Do you drive in a cold climate? Do you routinely log highway miles? Will you have reliable access to charging at work? For example, if you know you will operate your EV in cold temperatures without access to charging throughout the day, it is a great idea to get an EV with a range that exceeds your actual daily mileage.

Final Thoughts

While there is no doubt that range continues to be the primary consideration for both current and potential EV drivers, automakers continue to bring increased efficiency to consumers. Innovations are allowing vehicles to maximize their climate controls and mitigate range loss from extreme temperatures. Charging stations, like those provided by EV Connect, are becoming more prevalent, helping to assuage range concerns. And EV batteries are becoming more powerful with less degradation, meaning your EV will carry you great distances for years to come.

Sources

Environmental Protection Agency (EPA) - Explaining Electric & Plug-In Hybrid Electric Vehicles

US Department of Energy Alternative Fuels Data Center (AFDC) - Electricity Basics

US Department of Energy Fuel Economy - Fuel Economy in Cold Weather

Consumer Reports - Buying an Electric Car for a Cold Climate? Double Down on Range

Car and Driver - EV Range: Everything You Need to Know

Road Show by CNET - EV range: Maximize an electric car's potential

7 Factors That Affect Electric Vehicle Range

There are many factors that affect electric vehicle range. Just like with ICE (Internal Combustion Engine or gas) vehicles, electric vehicles (EVs) experience reduced efficiency during certain conditions. While some of these factors can be mitigated through driving behavior, most are just the realities of real-world driving.

The EPA may rate a vehicle for a certain efficiency, say 141 MPGe (Miles per Gallon Equivalent) for the Tesla Model 3 Standard Range Plus, but in reality, the range may be lower due to these particular factors.

Factors That Affect Electric Vehicle Range:

1. Speed

Speed kills. Tongue-in-cheek joke aside, driving at high speeds (65+ MPH) reduces the electric cars efficiency. The reason for this is the faster you drive, the more work the electric motor has to do. Anecdotal data from Teslike shows the impact on range from increasing speeds as shown in the below image.

As you can see, the Model 3 Standard Range Plus with the aero wheels has an EPA rating of 240 milesthough currently it is now rated at 250 miles. At 65 MPH the range is right at the current EPA rating. However, at 70 and 75 MPH the range decreases to 232 and 213 miles, respectively.

In essence, expect about 15% loss of range when driving at 75 MPH. This is consistent with my 2017 Chevy Volt. The Volt is rated at 53 miles per charge (its a plug-in hybrid so there is another 350+ miles of gas range after the battery is depleted). At speeds of 75 MPH I routinely see only 44 miles or so.

2. Wind

Another factor that affects electric vehicle range is windheadwind that is. This one is fairly straightforward. The higher the headwinds, the more resistance the vehicle experiences, therefore, the motor has to work harder to combat the negative effect. Unfortunately, there is not much data behind this yet to put a quantitative percent decrease per wind MPH.

3. Payload

Like wind, the more payload the more the motor has to work to offset the weight. There is minimal data to, again, quantify this as a percent decrease per payload weight. However, it is safe to say the more passengers and cargo you load into the vehicle, the less efficient the EV will be.

4. Tire Traction

Poor tire traction results in less efficiency. The three factors that contribute to tire traction are tire quality, tire inflation, and road conditions. If you are driving an EV with tires that are at the end of their life and the roads are wet from rain, then you can expect the range to slightly decrease.

Additionally, under-inflated tires will not only not perform as well, but will also not be as efficient. Poor tire traction will not impact range as much as speed, however, it still plays a part in range loss.

If you are in need of new tires, check out Tire Rack. Tire Rack is an online tire store where you can find the best tire deals. You can even ship the tires to your address or your preferred tire shop for easy installation.

5. Cold Weather

The cold ambient weather is unfriendly to electric cars. Specifically, EV batteries are not fond of cold weather. This is because they need to operate at a neutral temperature. Excessive cold, or excessive heat, will result in loss of range.

During cold ambient temperatures, the battery will need to use energy to heat itself up. With an ICE vehicle, the engine block creates a vast amount of heat (that is wasted to the environment), which can heat up the cabin, fuel, or other vehicle parts and functions. Naturally, the ICE vehicle warms itself up for optimal operation. With an EV, that heat needed to warm essential parts and functions must be created using energy from the battery.

During cold weather (below 50 degrees Fahrenheit), you will start to find a slight drop in range due to the battery needing to warm up. Below 30 degrees, the range loss becomes more apparent. In a study by AAA, electric cars experience a range loss of 12% in 20 degree F temperatures. And that is with the HVAC (Heating Ventilation Air Conditioning) off.

This leads to the next factor that affect electric vehicle rangeHVAC.

6. HVAC

Utilizing the HVAC, or heating in this case, during cold ambient temperatures will result in range loss. Simply put, using the heating system uses energy, therefore, range is lost from the battery using energy to heat the car rather than to move the wheels.

A typical car heating system consists of a radiator, water pump, thermostat, blower motor, and coolant. With an ICE vehicle, the natural heat byproduct from the engine is used to heat the cabin. With an EV, that heat must be created (so to speak). Energy from the battery, just like when the weather is cold, must be used, but in this case, to warm the cabin.

Per the aforementioned AAA study, EVs can experience as much as a 41% loss of range when using heating when ambient temperatures are 20 degrees. It is important to note that that decrease in range is coupled with HVAC use and ambient temperature rather than a multiplier to the previous cold weather section. Regardless, it still can be eye opening. ICE vehicles, too, experience similar, but not as drastic, loss of efficiency with both cold weather and HVAC use.

Lately, electric cars are outfitted with heat pumps rather than the electric resistance heater to combat this loss of range during heating use. Essentially, a heat pump is like a refrigerator, but in reverse when heating (see above image).

Vehicles like the Kia Niro and Tesla Model Y have a heat pump, which can be as much as 350% more efficient than electric resistance heaters. This significant increase in the efficiency of the heating system will result in much less loss of range during cold weather HVAC use.

7. Battery Degradation

Lastly, battery degradation is a major factor that affects electric vehicle range. A brand new electric car will have a State of Health (SOH), which is the amount of battery energy available compared to when new, of 100%. Therefore, battery degradation, obviously, will not have any impact on the range since there is none at this point.

However, over time the battery slowly loses capacity. Unlike cell phone or laptop batteries, electric car batteries include a Thermal Management System (TMS). This ensures the battery to last as long as possible.

The subject of battery degradation can be quite extensive. Check out an article dedicated to just this topic here: Electric Car Battery Degradation.

Back to the subject of factors that affect electric vehicle range, EVs experience around 2% of battery capacity loss per year. There are many factors that increase or decrease this statistic so it is important to read the battery degradation article to learn the specifics.

Closing Thoughts

While this list may seem long to some, there are several things drivers can do to reduce the loss of range such:

• Wear a jacket instead of using the car heater
• Drive under 70 MPH on the freeway/highway
• Accelerate slowly
• Pre-heat the cabin while still plugged in to reserve the battery for the trip
• DC Fast Charge only when you need to
• Upgrade to the heat pump trim if available (e.g. Kia Niro EV)
• Replace weathered tires with new
• Properly inflate tires

With this information, EV drivers should be better prepared to hit the roads without unexpected loss of range. Typically, I use a 25% range loss during a winter season long trip. This rule of thumb is subject to change as previously mentioned, however, it gives me a good starting place of how much range Ill have given the applicable factors (e.g. cold weather, heater use, highway speeds, etc.). Your specific results may vary.

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