• Mar 20, 2014
The AAA sent out a new press release today warning about the effects of extreme temperatures on electric vehicle range. The numbers are kind of astounding: "nearly 60 percent lower in extreme cold and 33 percent lower in extreme heat." Wow, right? Well, sort of.

The AAA ran a simulated EV test using a dynamometer and a climate-controlled room set for three temperatures: cold (20 degrees F), warm (95) and hot (105). In the tests, the "average EV battery range" for the three temperatures was 43, 69 and 105 miles, respectively. While we certainly agree with the AAA that EV drivers need to recognize that range will drop in the winter, there's more to the story.

The image shows the distances driven in my 2007 Honda Fit after four different tanks.

The image above shows the distances driven in my personal 2007 Honda Fit after four different tanks. I took the top two pictures last summer, when it was warm, and the bottom two in February, when it was most decidedly not. The tanks on the left were when I was driving normally and the ones on the right were where I was much more careful, shifting to N and coasting long before coming to a stop and accelerating slowly, for example. In the worst case, my roughly 9.5 gallons took me just 310 miles. In the best, 384, a 74-mile per tank difference. These were not scientific tests, but are enlightening nonetheless and show that temperature and driving style affect all cars, not just EVS.

You can test this out in your own car, no matter what the powertrain. The EPA also has a helpful resource about Fuel Economy in Cold Weather for gasoline and hybrid vehicles. The upshot is that a decrease of about 12 percent is common for gas cars (at 20 degrees F compared to 77 degrees) and about 32-33 percent for hybrids. The EPA also explains why cold weather impacts your efficiency, and some of the reasons do not apply to EVs:

"Engine and transmission friction increases in cold temperatures due to cold engine oil and other drive-line fluids.
It takes longer for your engine to reach its most fuel-efficient temperature. This affects shorter trips more, since your car spends more of your trip at less-than-optimal temperatures. ...
Colder air is denser, increasing aerodynamic drag on your vehicle, especially at highway speeds.
Tire pressure decreases in colder temperatures, increasing rolling resistance.
Winter grades of gasoline can have slightly less energy per gallon than summer blends.
Battery performance decreases in cold weather, making it harder for your alternator to keep your battery charged. This also affects the performance of the regenerative braking system on hybrids."

So, yes, make sure you've got enough juice in your battery to get home this winter. It's just as important as making sure you've got enough gas.
Show full PR text
Extreme Temperatures Affect Electric Vehicle Driving Range, AAA Says

New study conducted by the AAA Automotive Research Center shows electric vehicle driving range can be nearly 60 percent lower in extreme cold and 33 percent lower in extreme heat.

ORLANDO, Fla., March 20, 2014 /PRNewswire-USNewswire/ -- Electric Vehicles (EVs) are energy efficient and environmentally-friendly with the added benefit of reducing fuel costs for motorists. But, just as motorists need to know how far the gas in their tank will take them, EV drivers need to be aware of how far their vehicle can travel on a single charge. According to new AAA research conducted with the AAA Automotive Research Center in Southern California, electric vehicle range can be reduced by an average of 57 percent based on the temperature outside.

"Electric motors provide smooth operation, strong acceleration, require less maintenance than internal combustion engines, and for many motorists offer a cost effective option," said John Nielsen, managing director, AAA Automotive Engineering and Repair. "However, EV drivers need to carefully monitor driving range in hot and cold weather."

To better understand the impact of climate on electric vehicle batteries, AAA conducted a simulation to measure the driving range of three fully-electric vehicles in cold, moderate and hot weather. Temperature made a big difference in driving range for all three EVs.

Vehicles were tested for city driving to mimic stop-and-go traffic, and to better compare with EPA ratings listed on the window sticker. The average EV battery range in AAA's test was 105 miles at 75°F, but dropped 57 percent to 43 miles when the temperature was held steady at 20°F. Warm temperatures were less stressful on battery range, but still delivered a lower average of 69 miles per full charge at 95°F.

AAA performed testing between December 2013 and January 2014. Each vehicle completed a driving cycle for moderate, hot and cold climates following standard EPA-DOE test procedures. The vehicles were fully charged and then "driven" on a dynamometer in a climate-controlled room until the battery was fully exhausted.

AAA has initiated several projects including mobile recharging units and EV charging stations to support members who drive electric vehicles. EVs provide owners with many benefits, but every motorist needs to be aware of conditions that can impact vehicle driving range. EV drivers need to plan carefully in hot and cold weather. Mapping tools such as the AAA TripTik® Travel Planner pinpoint charging stations to keep motorists on the go.

Additional information regarding AAA's electric vehicle testing is available on the AAA NewsRoom.

As North America's largest motoring and leisure travel organization, AAA provides more than 54 million members with travel, insurance, financial and automotive-related services. Since its founding in 1902, the not-for-profit, fully tax-paying AAA has been a leader and advocate for the safety and security of all travelers. AAA clubs can be visited on the Internet at AAA.com.


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  • 47 Comments
      Rotation
      • 9 Months Ago
      It's not nearly as important to be sure you've got enough gas because you can pick up gas along the way easily.
        Spec
        • 9 Months Ago
        @Rotation
        And you start with a tank that holds much more gas. So yeah, it certainly does effect gas cars too but it is much more important issue with EVs due to the limited range and long charging time. EVers can't stick their heads in the sand about this. It needs to be addressed with good thermal management systems. For example, thermal management systems should keep batteries warm with an electrical heating system when the car is plugged-in during cold weather. Grid electricity is cheap and if the weather is cold, EVs should use grid electricity to keep the batteries warm to ensure good operation.
      Jim Illo
      • 9 Months Ago
      "So, yes, make sure you've got enough juice in your battery to get home this winter. It's just as important as making sure you've got enough gas." While true, there are some big differences between ICE cars and EVs. First, no EV has a 350+ mile range, but most ICE cars do. Second, gas/diesel stations are ubiquitous, fast-charge EV stations not so much. Third, gas stations 'recharge' and ICE car at a rate of over 100 miles per minute, vs. the vast majority of electric charging stations that charge a rate of less than 1/2 mile per minute. Even Tesla Superchargers only recharge at a rate of 8 miles a minute in ideal circumstances. That being said, the convenience of having a home fueling station (i.e. an outlet) is why I have a Chevy Volt.
        Greg Glockner
        • 9 Months Ago
        @Jim Illo
        Spot on. An EV is perfect for around town, especially when you have access to charging at the destination. EVs besides Tesla are not well-suited to long distance driving, and even a Tesla is less convenient than a traditional fueled vehicle over long distances.
        RyanC
        • 9 Months Ago
        @Jim Illo
        Thank you for that last comment. The great thing about an EV is that you wake up every morning with a "full tank." Not sure what your commute is like, but if you had charging abilities at work and at home, you could foresee-ably use no gas during a standard work week, assuming you don't travel.
          Jim Illo
          • 9 Months Ago
          @RyanC
          You're welcome. :) I'm pretty much the ideal customer for the Volt. I have a 20-mile round-trip commute. I occasionally have some side-trips after work, but rarely go more than 40 miles on a weekday. Once or twice a month we have a 120-mile round-trip to visit family (where I sometimes fully recharge). And three or four times a year we do a 400-mile weekend trip in the Volt to visit family. Even before I got the Volt, we always rented a larger vehicle for longer vacations (to bring all our toys, and to minimize the impact of a breakdown far from home). Just checked Voltstats, and I'm at 83.7% electric in over 34,000 miles.
        Aaron
        • 9 Months Ago
        @Jim Illo
        A SuperCharger at the newly-raised 120kW rate charges at around 270 miles per hour or 4.5 miles per minute. That's faster, in one minute, than my car with its 120V EVSE in one hour!
          Jim Illo
          • 9 Months Ago
          @Aaron
          Actually, full charge in 90 seconds wouldn't work for us. Our 400-mile family trips are usually round-robin, i.e. we don't cover the same route on the way home. As I understand it, Tesla's swap stations require you to come back to the same station and switch back to your original battery. But a 50+% charge in 20 minutes will actually work for us because there are Superchargers along both routes.
          Jim Illo
          • 9 Months Ago
          @Aaron
          I guess I was being generous at 8 miles per minute. Just did a search: the new 135KW Superchargers can charge at rates up to 370 miles per minute, or just over 6 miles per minute (of course that's with a nearly fully depleted battery - it slows down substantially once the battery gets over 75% charged). Even though I like the convenience of my Volt, to be honest if Tesla does bring out 200+ mile range car under $40,000 it may be my next car.....
          Joeviocoe
          • 9 Months Ago
          @Aaron
          Tesla doesn't "require" you return to pick up your battery. It was mentioned specifically that other arrangements could be made to send the pack to your final destination. Of course, that type of need will likely cost more than gasoline for that trip. But I think the idea is,... if you want speed like gasoline pumping, you can pay equal for it. Which is still a great deal if you have options to only pay for swaps when even 30 minutes is too slow. All in all... the OPTIONS are what give us freedom. Even if swapping winds up twice as expensive as Gasoline... EV drivers can limit themselves for when they absolutely need to be in a rush.
          Joeviocoe
          • 9 Months Ago
          @Aaron
          Full charge in 90 seconds work for you? Swap Stations trials in California in a few months... tentatively.
      Ryan
      • 9 Months Ago
      That drop in EV miles seems a little much. Especially with an insulated pack and heating pads. Now, running a heater inside the cabin will cause the numbers to drop that much. And yes, I do notice the same thing with my Saturn ICE car. In the Summer I can go about 25% further on the same amount of gas on the same highway trip.
        Aaron
        • 9 Months Ago
        @Ryan
        One thing EV drivers must adapt to is minimal use of the heater. Just for giggles, I turned my heat way up on a below-freezing day. My range dropped about 40%. If I kept it at "at least I'm not gonna get frostbite" heat levels, I only notice a 10-15% drop in range. (i-MiEV with old-style resistive heater)
      Jon
      • 9 Months Ago
      What a silly article. Yes cold affects ICE's too but the point is if your EV runs out of juice you are SOL. Places to quickly refuel your ICE are fast and plentiful. And from 100 miles of range to 40 is a much bigger deal than going from 380 to 310. I'm pretty sure you will still make it home from work. I as big an EV advocate as there is but this article is just pointless trolling.
        Aaron
        • 9 Months Ago
        @Jon
        If your EV runs out of juice, the driver did a poor job of planning his trip.
          Jon
          • 9 Months Ago
          @Aaron
          Obviously. The point is that cold weather effect on range is still a much bigger deal to an EV than it is to a conventional vehicle. Look, I am a huge EV advocate. I have done EV conversions. You can still be an EV fan without being blind to the negatives.
      2 wheeled menace
      • 9 Months Ago
      It's the use of battery power for heat that "kills" range. This problem is solved with an external liquid fuel heater. Oldschool EVs used kerosene/propane heaters to get around this.. the solution should be soobvious that it isn't even discussed, but hey, why not make people fearful of electric cars... oil execs gotta put caviar on the table, ya know..
        Harry
        • 9 Months Ago
        @2 wheeled menace
        2WM, I don't know about BEV's, but my Volt goes from 46 miles of range down to 26-28 miles when the temps are between 15 and 25 degrees. I use the heat on Eco 1 or 2 only, which doesn't seem to affect the draw on the pack much at all, maybe 10% of the resting rate of draw. At a stop, my car usually draws at a 0.5 kW rate. In the winter cold, whether I use heat on Eco 1 or 2 or not, the Volt draws at a 2.0 kW rate. If you you use Comfort the draw goes up to 3 or 4 kW rates. Eco 1 and 2 seem to draw around 150 to 250 watts, respectively. Those figures are just estimates, of course, but they seem to be what my dash shows on cold days. It doesn't appear that the heater is the reason the range drops, it is something else.
        Spec
        • 9 Months Ago
        @2 wheeled menace
        It is a tough call. Adding such a heater would help range but adds complexity, cost, maintence, etc. to the vehicle. It is probably worth it in really cold places but not worth it for milder places. Make it an option.
        2 wheeled menace
        • 9 Months Ago
        @2 wheeled menace
        I'd think that gaining ~20% of your range back and putting less wear and tear on your battery would be worth some awkwardness.
        2 wheeled menace
        • 9 Months Ago
        @2 wheeled menace
        Yes, the automakers *should* install them at the factory. But they also should design EVs much better. A lot of production EVs are still kind of half-assed compared to what they could be. You could definitely install an aftermarket heater properly if you know what you're doing, but i know what you mean about deadly. There are two types of propane heaters for example.. one that is a more expensive dual stage type, and the other that, well, has tons of warnings about indoor usage that if ignored, would be a suicide machine.
        karlInSanDiego
        • 9 Months Ago
        @2 wheeled menace
        Fiat 500e (via Bosch) has this already (liquid cooled/heated battery and motor), and they already clarified that this gave them much less variance with temperature. Focus has same ideology. Reading the AAA article: "Tests were conducted on a 2013 Nissan Leaf with a factory heating unit dedicated to the battery pack; and a 2012 Mitsubishi iMieV and 2014 Ford Focus Electric with dedicated active thermal management (heat and A/C) for the battery pack." Nissan(optional and used in this test), Mitsubishi (optional and not used in this test???) and Tesla have battery heaters dialed in as safety measures against battery freezing (activate at 20 degrees F) and only active when plugged into the wall. Think if this like an electric dipstick traditionally used in extreme temps to keep oil warm enough to function at startup. None appeared to have attacked the thermal management as a way to ensure consistent range in varying temperatures. Ford, like Fiat uses liquid cooling and it's active while the car is operating. Did two cars let the third down, dropping all three's avg. because they aren't active or liquid, or in iMiEv even included? Study should have taken the time to break out the results by car, as this will become an important differentiator between designs.
        Joeviocoe
        • 9 Months Ago
        @2 wheeled menace
        For the automaker to install a fossil fueled heater in an EV would also cause a legal/regulatory battle against getting full Zero Emissions credits and other incentives.
        Actionable Mango
        • 9 Months Ago
        @2 wheeled menace
        "the solution should be so obvious that it isn't even discussed" If the solution is so obvious, the automaker should install one at the factory. When people stick a third party heater into a car it will be awkward at best, and dangerous or lethal at worst.
      Electron
      • 9 Months Ago
      I wonder which models were tested. From what I could find Model S could loose up to 25% of range in winter, nowhere near the 60% AAA is throwing around. A lot also depends on preheating the car and the battery, did they do that? Or do we have to put this one in the same category as AAA's support for the oil industry's war on ethanol?
      Marco Polo
      • 9 Months Ago
      The AAA is simply stating the obvious. Battery performance suffers in extremely cold conditions. That's hardly a new fact. I don't understand why anyone would criticise the AAA for providing such information. EV technology is not so fragile, that any negative observation should be automatically attacked. The degree of heat or cold affecting an EV's battery performance, is dependant of a wide range of factors, but it's part of the learning process of EV ownership. If this degree of range efficiency is a real problem, then an EREV might be a better choice. I try to avoid the Northern hemisphere winter as much as possible, but this year I spent December in the UK. I was interested to see how the cold weather affected the performance of my EV. Even with the heating operating the LERR only lost about 8-12% of it's 200+ range. Considering the extra power used by the 4WD, that small drop in battery range, isn't bad for such a large vehicle. EV ESD technology is evolving rapidly and each generation, will be more robust and store more energy than the previous generation.
      Aaron
      • 9 Months Ago
      I like the shots of winter/summer/normal/hypermiling. So, why does your power steering fail in the winter? (Just kidding!)
      BipDBo
      • 9 Months Ago
      "So, yes, make sure you've got enough juice in your battery to get home this winter. It's just as important as making sure you've got enough gas." No, it's much more important because gas stations are everywhere. Also, if you drive an EV other than a Tesla, your warm weather range is only around 80 miles. Most gas cars have a range of at least 300 miles. If you get, low, you just pull into the next station and leave with a full tank in about 5 minutes. Not a problem. I'm an EV fan, but this is a fanatically dishonest and stupid article.
        itsme38269
        • 9 Months Ago
        @BipDBo
        Gas stations are everywhere? How about in your garage? Is there a gas station there? In fact, in cold weather, gasoline vehicles will be more affected, on a cost basis, than EVs will be. Here's the stats on it: http://news.fleetcarma.com/2014/01/16/cold-weather-fuel-efficiency/
          BipDBo
          • 9 Months Ago
          @itsme38269
          AAA is making the warning based on the probability of EV drivers getting stranded because of an unforeseen drop in range. While it is convenient to charge at your own home, you can't charge in some stranger's garage away from your home, so your statement is meaningless in the context of range anxiety, which is what AAA is addressing. They are not talking about convenience or fuel cost. Their just trying to sell towing insurance by putting the fear of the very real possibility in your head of being stranded in the freezing cold with a dead battery.
        thecommentator2013
        • 9 Months Ago
        @BipDBo
        While that might be right, but who needs a range of 300mi+ on a daily basis? Most people have a commute of around 40mi+/-. That's why an EREV makes so much sense. If yo don't believe it it's because you don't have one. Those who do confirm my statement. With an EREV you have no such thing as range anxiety and you hardly have any fuel consumption. Best of both worlds so to speak. It's just hard for people to realise.
      o e
      • 9 Months Ago
      unless we invest hundreds of billions of dollars into the building of new nuke plants and new fossil fuel plants..... the electric car is DOOOOMMMMEEED ! ! ! p.s. dont forget the new power transformers... OR the stringing up of new high voltage power towers and transmission lines... can you say HUNDREDS OF BILLIONS ! ! Fact, there is not enough mineable lithium on earth currently available to meet CURRENT requirements for 10s of millions of electric cars ! ! SOOOO, until there is a new kind of battery that uses VERY little lithium or no lithium, we are just spinning our wheels here. It is not some piece of cake operation to recycle waste lithium into next generation batteries either. SCALE, SCALE SCALE, the factories that would have to be built would take YEARS to get up and running to scale up to the size of transitioning America to electric cars. People have this idea that is simple or easy to change fabrication methods over with a flick of a wand or a snap of a finger. CREDIT, where will 100,000,000, yes where will 100 million car owners get the cash or credit line for a new car that is electric.... AHHHH yes catch 22. If america transitions to electric cars 2 horrible things happen, the " haves" will be fine, there will be a glut of gasoline cars on the market. BUT even the haves will have to eat crow when it comes to trading in their gas cars. The problem will be the people that are on the bottom rungs of the economic ladder will be least able to switch over to electric cars. 1st they have no credit to get a new car, SECOND they dont have the income that would alow them to buy such a LUXURY, 3rd gas prices will go up !! When demand starts to dip for gasoline and production is lowered prices will go up for gasoline !! If about 50 percent of americans by some credit and income miracle are able to buy an electric car the 50 percent that have gas cars will pay more for gasoline. An oil and gas refinery have SET COSTS, those set costs of production are ABSOLUTE, thus as the gasoline production is scaled down the cost per gallon goes UP ! ! Banks will have no choice but to raise interest rates on car loans for gasoline cars, realizing that more of their clients money will go to the gasoline charge, and THUS THE RISK OF THE LOAN GOING INTO DELINQUENCY BECOMES GREATER ! !
        Joeviocoe
        • 9 Months Ago
        @o e
        You don't even know how much lithium is currently used. Everything in your post is just wrong,.... in fact, opposite of reality. TROLLING alert!
      brotherkenny4
      • 9 Months Ago
      AAA is called a club, but is a business. They are not independent of the financial alterations that EVs will have on various vested interests, including themselves. Additionally, the general intelligence that EV drivers have (the evidence is they don't believe the false rhetoric and fear mongering that has surrounded the EVs) does not make the EV drivers likely to see AAA as a reasonable organization to join, because their existence and purpose is financial, and even before EVs fearmongering, driven by fear of what is out there on the road. In other words, AAA exists because of the imagined fears people had of breaking down on the road, and "Oh my, what ever shall I do if that happens".
        karlInSanDiego
        • 9 Months Ago
        @brotherkenny4
        Correction. AAA is not a traditional business. From their website, and from personal experience with them as a long time member: AAA, a not-for-profit, fully tax-paying corporation, is a federation of affiliated motor clubs with more than 1,100 offices in the U.S. and Canada. It offers personal service through its network of more than 40,000 full-time employees. As a motor club, they do not try to grow their profits and pay their owners or shareholders because it has neither. Of course, they have to pay their employees and keep their books working so they have to balance costs with fees, but they are not-for-profit. Also, your assessment that their members are imagining they need their services is an ignorant one. I use them often with my classics and often enough with my moderns, and they save me from getting my ass kicked with gnarly towing rates, once I got RV/Motorcycle and extended tow range coverage. Their motorcycle insurance rates were half that of Allstate, so they got that business from me now too.
      scotty Ø
      • 9 Months Ago
      I've seen similar MPG differences with both my Fiesta and Focus. Both get several MPG less during winter months than in summer.
        Letstakeawalk
        • 9 Months Ago
        @scotty Ø
        Try a warm-air intake to increase cold weather mpg.
          karlInSanDiego
          • 9 Months Ago
          @Letstakeawalk
          Cold air creates more power not less, because the charge is more dense, so it increases your compression increasing your efficiency per stroke. The only benefit you might get from a warm-air intake is to help get the rest of the engine/cat up to temperature where both work better. An infinitely hot motor (so no energy is lost to heating it) with infinitely cold charge (assuming your fuel wouldn't freeze) would create the ideal efficiency and power. Obviously, real world pisses on that formula a bit.
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