How Temperature Affects EV Range

How Temperature Affects EV Range

How Temperature Affects EV Range: It’s well established that cold weather takes a toll on the range for electric vehicles, because the car must manage both battery and cabin temperatures, causing a significant drain. But by how much? And what about warm weather? Over the past year, Consumer Reports sought to answer these questions by conducting seasonal testing on popular new all-wheel-drive EVs: the Ford Mustang Mach-E extended range, Hyundai Ioniq 5, Tesla Model Y Long Range, and Volkswagen ID.4 Pro S.

Each car was tested in the exact same manner, by the same drivers, driven in a caravan on three different days: a frigid one, a mild one, and a warm one. We found that cold weather saps about 25 percent of range when cruising at 70 mph compared with the same conditions in mild weather. In the past, we found that short trips in the cold with frequent stops and the need to reheat the cabin saps 50 percent of the range.

Unlike a gas car, where the heat is free, coming from the engine, an EV has to produce cabin heat and manage an optimal battery temperature with energy that comes from the battery, in turn reducing range. (It’s worth noting that gasoline engines are typically less efficient in cold temperatures, as well.)

We had an expectation that mild weather in the low 60s would provide the greatest range, but actually, the warm 80° F temps provided the longest range of the three tested conditions.

This test shows that EV range isn’t an absolute metric. Weather, hills, speed, traffic, cargo, passengers, and climate settings can have an impact. That said, this ongoing experiment provides key insights into the role weather plays with range.

What We Found

This test series underscores the importance of taking range claims as general guides and being mindful of the “moving target” nature of EV range. Another difference between ICE (internal combustion engine) cars and EVs is that during constant cruising, an ICE car attains its best fuel economy. An EV, on the other hand, isn’t at its optimal efficiency when cruising on the highway, with limited opportunity to benefit from regenerative braking—energy that’s recouped from braking and coasting that gets directed back into the battery.

Because the Environmental Protection Agency (EPA) range is based on a mix of city and highway driving, the expectation for a test like this is that the vehicles should slightly underperform their rated range age at a constant highway speed.

We found a clear trend among these models showing that under different seasonal temperatures, winter cold results in the shortest range, followed by mild temperatures. It was on a typical summer day of sunny, humid, mid-80-degree weather that we saw the longest range, despite using air conditioning.

Other findings showed that the Mustang Mach-E stood out for having the most accurate range prediction—the indicated range used vs. the actual miles driven. Its real-world range also came within 1 or 2 miles of the Model Y on every run, even though the Model Y has a higher official EPA range. Note that the Mach-E has the largest battery of the bunch, at 88 kWh of usable capacity. And the Model Y is the lightest vehicle of the quartet, differing by more than 500 pounds from the ID.4, which is the heaviest. Of the two runs we performed with the Ioniq 5, it came the closest to its EPA rating.

How We Tested

We began testing in frigid February 2022, repeating the procedure in balmy April and in August heat. Of these four models, we have results from only two seasons for the Ioniq 5 because of when we purchased our tested car. We will follow up with the Ioniq 5 in the winter.

The EVs were fully charged overnight before each of the runs and were allowed to precondition the cabin to 72° F while still plugged in outdoors. At the same time, we checked and verified the tire pressure. Heated and cooled seats weren’t used.

On the cold day, the temperature averaged 16° F (-8° C), meaning that considerable energy was needed to keep the cabin comfy and the battery pack in its ideal operating condition. The mild spring day was 65° F (18° C) during most of the drive, and the warm summer day was 85° F (29° C) during the drive. Each test day was clear and sunny.

The cars were taken on the road concurrently and driven on the same 142-mile round trip route of Connecticut Route 2 and I-91. We used adaptive cruise control set to 70 mph and the widest gap to prevent any aerodynamic trailing effect or sudden decelerations and accelerations due to surrounding traffic. The regenerative braking mode was set to its lowest setting for each car. We paused for 10 minutes with the cars off at the midpoint.

See how temperature affects the range of your EV

How far can you drive in minus 20 degrees? And how hot does the temperature have to be before it actually prolongs your EV’s estimated driving range? Explore how the weather affects your EV’s driving range right here.

EVs’ driving range is one of the most discussed subjects for people thinking about buying an EV. And with good reason. It is a fundamental different way of transportation and you wouldn’t want to end up buying a car that can’t get you to work without having to stop and charge on the way. But even if you do your homework and read up on potential EV’s estimated driving range, many other factors still play a role in deciding how many miles an EV can actually cover without having to stop and recharge.

Weather Impacts Depend on Model and Battery Chemistry

Temperature impacts battery performance differently depending on battery type and overall vehicle engineering. Features such as a heat pump, advanced battery preconditioning and even heated seats are just some of the many ways that engineers can do their best to optimize EV performance in suboptimal weather.

EV data specialists at Recurrent looked at data from all of the popular electric vehicle models. They found that EV range in hot and cold weather varies widely from one make and model to another.

Here’s how some of America’s most popular electric vehicles are affected by cold weather and summer heat.

Model Rated Range Real-World Range (70 deg F) Cold Weather Range Loss
Tesla Model 3 353 miles 339 miles 335 miles (-5% from rated range)
Tesla Model Y 330 miles 320 miles 323 miles (-2% from rated range)
Tesla Model S 405 miles 397 miles 380 miles (-6% from rated range)
Tesla Model X 351 miles 326 miles 326 miles (-7% from rated range)
Ford Mustang Mach-E 305 miles 284 miles 198 miles (-35% from rated range)
Chevrolet Bolt 259 miles  254 miles 171 miles (-34% from rated range)
Nissan Leaf 226 miles 237 miles 205 miles (-9% from rated range)
Hyundai Kona 258 miles 288 miles 240 miles (-7% from rated range)
Audi e-tron 222 miles 224 miles 206 miles (-7% from rated range)

 

The temperature affects the range

You’re more likely to turn up the heat if you’re driving around when the weather is cold, while a hot summer day nudges you to turn on the air conditioning. Both actions have a tremendous impact on your EV’s battery capacity.

Geotab, which is an analytics company, has investigated 5.2 million rides driven by 4.2000 EVs split between 102 different brands and models. The research shows that

Temperature has to a large extend the same effect on EV’s driving range across different brands and models.

Cold and hot temperatures both have a negative impact on EV’s driving range. Cold weather is the worst.

21.5 celsius is the optimal temperature for EVs when it comes to driving range.

Below, you can see how different kinds of weather affects your EV’s driving range. “Rated range” is the car’s estimated range from the manufacturer.

Don’t let the cold confound you

You will lose range – don’t be worried, be informed. As battery sizes have increased with new EV models, range loss has become less of an issue. Larger capacity means little impact on most daily trip needs, and charging infrastructure continues to expand for that occasional road trip. Knowing your daily distance needs will ensure you choose the right vehicle for you or for your fleet.

Electric Vehicles in Cold Weather

Cold weather reduces EV range, but how much depends on how toasty you keep the cabin. Sub-freezing temperatures reduce range by between 12% and 30%, but that’s without the climate control on to warm the cabin. Data from AAA found that once the heater is turned on, EV range can drop by as much as 41%. Some real-world tests have found range losses closer to 50% with below-zero temperatures. That’s not good if you travel long distances across the northern states or the Interior West. More on specific impacts below.

Electric Vehicles in Hot Weather

Yes, hot weather does reduce EV range. According to research conducted by AAA, hot temperatures don’t have quite as great of an impact as cold temperatures, but it’s still noticeable. In temperatures of 95 degrees Fahrenheit and the air conditioning on, driving range decreases  by 17% on average.

A 17% drop in range would mean that a Model Y normally rated for 330 miles on a charge would get closer to 273 miles. Not too big of a deal. For electric vehicles with less EPA-rated range, it matters more. The standard range 2022 Nissan Leaf normally gets 150 miles on a charge, but that would drop to 124 miles in 95-degree weather. Ouch.

Does Rain Affect EV Range?

Rain, snow and anything else falling from the sky does lower EV range. Why? It creates drag, and EV efficiency is all about aerodynamics. The heavier the rain, the greater the impact on range, even if temperatures are perfect for battery performance.

Speaking of which, what is the ideal temperature for electric vehicle battery performance? Geotab’s analysis of data from 4,200 EVs found that 70 degrees Fahrenheit (21.5 Celsius) is ideal for battery performance. That’s not only perfect for maximum range, it’s great weather all around. Learn more in Geotab’s full report.

How Much Does Wind Impact EV Range?

Similarly, wind’s impacts on electric vehicle range have to do with drag. Drag is in essence aerodynamic friction. Your fancy new electric car can’t slide through the air so efficiently with friction working on it.

Wind can work against you or for you. With a steady tailwind pushing you along, it’s common to exceed range expectations even on the highway. When there’s a substantial headwind, range drops, and sometimes by quite a lot. The impacts of wind on EV range are much more noticeable at highway speeds. It’s possible to gain or lose up to 20% of expected range depending on wind direction.

Why your EV is affected by temperature

It’s highly likely that your EV’s battery consists of lithium, which is sensitive to extreme temperatures. The colder the weather, the thicker the electrolyte fluent will be in the battery making it difficult to retain energy as well as passing it through the system.

Your battery’s ability to perform in hot and cold temperatures, however, isn’t the biggest sinner of them all. The biggest sinner is your car’s heating system. EVs are designed to heat or cool off the battery in order for the battery to perform at its best. And because the optimal temperature for most batteries is between 15 and 30 degrees celsius, part of the energy is used to cover this need.

The car’s heating system is also a factor when it comes to air conditioning. If you’re driving around in minus 20 degrees you will likely turn up the heat, while a hot summer day makes you crave colder air in the cabin. Whether it’s the former or the latter the result is the same: the energy is used to control air temperature in the car and not to move the car.

To what degree does temperature impact EV range?

Understand how temperature affects how far your EV can go on a full battery.

With another winter behind us and a summer on the horizon, now is a great time to reflect on the impact temperature has on electric vehicle (EV) range. Following an in-depth analysis of EV data – drawn from 4,200 connected EVs and 5.2 million trips – we are better able to understand the relationship between temperature and how far your EV can go on a full battery.

Here we reveal the optimal operating temperature, how much range you might expect to lose in the dead of winter (or the peak of summer), and key takeaways on what you can do to extend the daily range of your EVs.

We are pleased to unveil our new Temperature Tool for EV Range that helps give vehicle operators confidence in knowing the expected range for a variety of EV makes and models at a given temperature.

21.5 degrees is the optimal temperature

On average, 21.5 degree Celsius is the most optimal temperature when it comes to your EV’s driving range. It actually prolongs it. At 21.5 degrees, the car’s temperature system isn’t active and, therefore, energy is used to move the car.

EV Temperature

 

The reality of EV range

When deciding on an EV to buy, range is often the first spec that’s considered. But as EV drivers know, the officially listed range (or how far a car can drive on a single charge) is best taken as a guideline.

While a vehicle’s published range is based on standardized testing performed on a dynamometer in a test facility, EVs, like gas cars, perform differently in real-life conditions depending on terrain, passenger load, speed, driver behavior or outdoor temperature. These factors all impact the vehicle’s efficiency and therefore its range.

A vehicle’s “fuel” efficiency (where fuel in the case of an EV is watt-hour, Wh) can be described in two ways:

Fuel economy is how far a vehicle can go on a given amount of fuel (think miles per gallon); for EVs this is km/Wh (or miles/Wh).

Fuel consumption is how much fuel a vehicle needs to drive a given distance (think liters per 100km); for EVs this is Wh/km (or Wh/mile).

While both are a measure of efficiency, as you can see, one is the inverse of the other. Fuel economy prioritizes distance, whereas consumption highlights the amount of fuel needed to travel a given distance. Multiplying the fuel economy by the battery size (generally measured in kilowatt-hours, kWh) will give you the vehicle’s range.

The more energy a vehicle’s battery pack can store, the longer its range, but this is impacted by the vehicle’s design (weight, shape, size, etc.) which sets the parameters of how efficient the vehicle can be. For a bus to go as far as a 60kWh sedan, it would need a much bigger battery.

Winter weather woes

The most notorious EV range-killer is cold weather. Since EVs first came to market, a frequent knock against them was that they didn’t work well in winter. While many Canadian and Norwegian EV drivers beg to differ, it is true that temperature is a culprit when it comes to range.

Day-to-day range is affected by temperature primarily due to auxiliary heating and cooling. Energy from the battery not only powers the vehicle, but also the auxiliary systems, most notably:

Heating and cooling the vehicle cabin

Heating and cooling the battery

People often assume range loss in cold temperatures is due to reduced battery performance.

While lithium-ion batteries are more sluggish in extreme temperatures (cold temperatures impact their ability to store and release energy), this has far less impact on range than auxiliary load. Additionally, automakers have designed battery thermal management systems to keep batteries within an optimal temperature range, further minimizing loss in battery performance (but costing us auxiliary load).

We set out to fully understand the impact temperature has on range, and whether all EV models were impacted equally. To find out, Geotab looked at anonymized data from 5.2 million trips taken by 4,200 EVs representing 102 different make/model/year combinations, and analyzed average vehicle trip efficiency by temperature.

Our analysis showed that

Most EVs follow a similar temperature range curve, regardless of make or model.

While both cold and hot temperatures impact range, colder climates have a larger impact.

21.5 C (70 F) is the vehicle trip efficiency sweet-spot.

Unveiling the temperature range curve

Temperature range curve

Temperature range curve

Our data shows that most EVs follow the same efficiency curve by temperature, irrespective of their make, model or year. Note: early analysis shows there may be slight variations with a few models, and we’ll be investigating these further for future posts.

The above graph shows the range an EV will get (on average) compared to its rated range at any given temperature. At optimal temperatures, EVs are performing better than their rated range, peaking at 115% at 21.5 C or 70 F. So, most EV owners are exceeding the rated range of the vehicle in peak temperature conditions. As you turn up or down the temperature, however, the loss of range is apparent. At -15 C (5 F), EVs drop to 54% of their rated range, meaning a car that is rated for 250 miles (402 km) will only get on average 135 miles (217 km).

Cold gets a bad rap, but it turns out heat is also culpable.

Interestingly, if you look closely you’ll notice the range drops slightly faster (the slope is steeper) as you increase temperature. The real-world impact manifests less in hot temperatures, however, as Earth’s climate doesn’t often hit temperatures beyond 50 C (122 F), so we don’t know (nor hopefully need to care) what happens to our range after that point.

The cost of being comfortable

It’s no coincidence that across the board the most efficient trips were taken on days where the average outdoor temperature was 21-22 C (70-71 F). Interesting fact: this happens to be the temperature at which we humans like to keep our homes.

If you get into your car and the temperature outside is below 20 C,  you are more likely to turn on the heat; above 22 C and you’ll probably switch on the AC. Getting the cabin temperature to a comfy house-like condition draws energy from the battery that could have otherwise been used to move the car.

Like humans, batteries also like to be comfortable and function best at moderate temperatures (although they’re a bit more cold-friendly and tolerate a wider temperature range). An EV’s on-board thermal management system is designed to draw energy to warm or cool the vehicle’s battery, as needed, to ensure it operates in that ideal range. Therefore, the car is working to heat/cool both the occupants and the batteries in cold or hot conditions.

Range curve with 10th and 90th percentiles

Range curve with 10th and 90th percentiles shows the distribution of trip efficiency one might expect at any given temperature.

Our range curve is based on the average efficiency of all trips in our databases taken at a given temperature. Because these trips were made in the real world, they were exposed to a wide variety of external factors that can impact vehicle efficiency such as terrain, speed, driver habits, trip length and start-conditions (e.g., if the trip started in a climate-controlled garage).

Overall, the best performers (those in the 90th percentile) obtained 32% more range than the average, and had twice the range as those in the worst 10th percentile.

Tips to extend your EV range on hot and cold days

As outlined, the major offender for causing range loss in cold and hot temperatures is auxiliary load. Therefore, minimizing auxiliary load will help extend those miles:

Take advantage of the amenities that come with your car – heat or cool the human, not the air. Be sure to use those heated seats and steering wheel. Heating the cabin air can draw 3000-5000 watts, and is much less efficient than heating your seat and steering wheel (around 75 watts) which transfers heat to your body via conduction. Using these increasingly common features can keep you comfortable without resorting to the cabin heater. However, in very cold temperatures, minimizing cabin heating can only take you so far, and you will still lose energy from your battery thermal management system.

Pre-condition your vehicle. Just like you would before exercise, warm up before a long trip! If it’s hot, cool down. Turning on your car’s heaters while it’s still plugged in will minimize the auxiliary load by warming (or cooling) your car before it starts its trip. Take advantage of the guilt-free pre-conditioning that EVs allow. If the option is available to you, park in a temperature-controlled garage to get a similar effect.

Keep your vehicle plugged in on extreme cold or hot days. In addition to the benefits of preconditioning before your trip, automakers recommend vehicles are plugged in during very hot or very cold days when the vehicle is not in use. (Note: this is not the same as actively charging, which is better to avoid in extreme conditions, particularly heat). Having a vehicle plugged in allows the internal system to maintain battery temperature controls, prolonging the life of your battery in the long run.

Tips to prolong your EV’s driving range

If you want to prolong your EV’s driving range under all types of weather conditions, we’ve gathered a few tricks to help you get a few extra miles on the road.

Turn on the seat and steering wheel heater instead of the normal heating system. The seat and steering wheel heater uses only 75 Watts of power compared to the heating system’s 3000-5000 Watts.

Preheat the car before you hit the road. When turning on the car’s heating system while it’s still plugged into your Kia EV4 Specificationscharge point, the car uses less energy from the battery.

 

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