AAA Posts Results From Extreme Temperature Electric Vehicle Range Study (w/infographic)

MAR 20 2014 BY ERIC LOVEDAY 31

AAA Study Shows EV Range Varies Dramatically Depending on Outside Temps

AAA Study Shows EV Range Varies Dramatically Depending on Outside Temps

“Electric Vehicles (EVs) are energy efficient and environmentally-friendly with the added benefit of reducing fuel costs for motorists.”

That’s the positive opening statement from a AAA press released titled “Extreme Temperatures Affect Electric Vehicle Driving Range.”

It goes all downhill from there though.  AAA continues:

“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.”

How did AAA arrive at that “range can be reduced by an average of 57 percent” conclusion?

Here’s the testing methods, as detailed by AAA:

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.

Do AAA’s percentages jive with what you’ve experienced?

AAA Range Infographic

AAA Range Infographic

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31 Comments on "AAA Posts Results From Extreme Temperature Electric Vehicle Range Study (w/infographic)"

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I wouldn’t say 43 miles at 20 degrees is accurate. During this past brutal winter in Chicago, when it was routinely below zero, I averaged 50 miles range with the heat set to 72 degrees.

Actually I found the triple A study the most accurate I’ve seen to date. Those figures mirror mine, but in stop and go rush hour traffic is when I get ridiculously low mileage, much less than a gasoline car would be.

Hats off to triple A to do a realistic study and not sugar-coat things.

That’s because, in stop and go traffic, your EV battery is taxed much more to keep you warm (simply due to your trip taking longer). In an ICE, this time has a much smaller effect since the engine is always spewing heat (wasted in warm weather) which can be used to keep you warm, regardless of trip duration.

I have a Ford Focus, btw

So… if you lost some 35% in worse weather, let’s say it’s 30% in 20-degree weather. They state a loss of 57% on average across 3 cars – a sum of 171%. Take away 30%, we’re at 140% on 2 cars.

Either these two cars (one of them being 2013 Leaf with improved weather-control efficiency) lost 70%, or their test is rigged.

Also, note that they don’t use the EPA range as reference – but rather some ideal “hypermiling” scenario in which the FEV, the Leaf and the lowly MiEV manage to average 105 miles per charge together.

A more realistic – and fair – description would be to say “you can exceed EPA range by 20-30% under ideal conditions, and come 20-30% short under very poor conditions.”

But that’s old news.

+1. Your conclusion is spot on!

That is true except at 43 miles compared to an average of 73 miles to 84 miles of BEV EPA range, that would be a drop of 42% to 49%, NOT your 20-30%.

I doubt it’s “rigged”, but it’s hard to get dyno tests “right”. There’s no true aero on a dyno, so they have to account for “drag” and other parameters like the curved tire patch from drum diameter artificially. It seems they created (or chose) a drive profile that wasn’t quite like the EPA cycle, but it’s not clear what it WAS like. It’s a losing game, since for ANY drive profile they choose, somebody will raise their hand and say they personally drive their car differently. Still, it’s nice that they tried to run all the cars against an objective procedure. I wonder if they added in the “right” terms to account for the missing resistances for each car, though. It’s a big project to try to get it all correct. That may explain their reluctance to release detailed results and just sharing aggregate numbers.

Is that in your Volt or your Roadster?

I assume this is for me: the volt is the most drastic since someone told me the heater is at least 6000 watts, plus with battery only operation the battery also must be heated in cold weather. Its not any ‘defect’ or anything, its just the nature of the animal. Electric heat (around here anyway), is very expensive, and even more so when you consider the charge/discharge inefficiencies, plus battery heating requirement. The roadster is normally not too bad, but in VERY cold weather it is almost impossible to charge. First thing is the trunk won’t open to get the adapter cable, second is the charge port door wont come on in cold weather (I have an unheated garage), since the switch has frozen in the closed position. A hair dryer at 1500 watt for 10 minutes usually thaws things out enough to work. But heating in the Roadster cabin is easier since it is diminutive. The impossibility in VERY cold weather is that the battery heater is only around 900 watts. It spends almost all its time heating the battery to prevent Lithium plating so that very little time is left over to actually charge the battery. Surprisingly, other… Read more »

It varies with battery chemistry particulars and whether or not the battery is thermally managed.

i would also point out that simple math has shown that, despite the decrease in range in plug-ins in cold weather, they actually save MORE money in cold weather compared with gas vehicles than they already save in warm weather.

It’s a bit non-intuitive given the huge efficiency hit, but it continues to be that much more efficient in cold weather than burning dino juice.

This is a great point, and one that is lost on all but the most resolute enthusiasts. However, cost of ownership and range are separate concerns. It’s of little consolation if one bought a BEV for their commute only to discover they cannot make the trip during the winter…

HI Brian

Got a question for you… How big is your solar system on your house? I’m getting bids for different systems as I’m going the solar pv route for my house.

Hey Bill,

I have 16 panels rated at 230W each, for a total of 3.68kW DC, or 3.119kW AC. Good luck with your surveys – I had a lot of fun digging through the analysis the various companies did for mine.

Thanks for the sizing information Brian! I tried American Freedom here, the guys came to the house, but had never seen a split-bus loadcenter before. I tried to explain to them that I was fully compliant with the NEC article which said the bussing has to be rated at least 83 1/3% of the overcurrent devices feeding the bus due to the solar generation and all other sources, but we’ve only agreed on 2 points so far, seeing as I don’t want any bandaid and bubble gummed supply side splices: 1). They had no problem installing a 3800 watt inverter (16 amps). 2). There are 2 inspectors that have to approve the system. If I can convince BOTH of them I’m in compliance, they will install a larger system. They will also allow me, for a discount, to provide the AC feed. So I’m getting something, even if it is only 3800 watts. Due to having 2 EV’s I’d really prefer a 5400 or 7000 watt system since the NY State tax credit is up to $5000 and the current NYSERDA credit is up to 7000 watts ($7000). It will be more old fashioned than yours since it will have… Read more »

The guy finally talked to the inspector, who will only allow 16 amps into the bottom of the lighting bus, which is beyond brain dead. I asked to speak to the inspector, but the installer didn’t want to for fear of being charged $, so I’m not sure the inspector realized what I have. He would alow a supply side spice so that’s what im doing. Seeing as I have 5 disconnects and am adding a 6th – they be ‘commonly grouped’ and I still have 6 disc or less. I have to redress things in my panel prior to pullingthe meter to attach 3 bugs to the main wires. I just ordered a revenue meter and round socket from Hialeah Meter.
From there it goes to another main lug panel, since I was told I need more than one inverter.

Just found the NYSERDA credit is $1 / watt up to 25000 (raised from 7000). Unfortunately, the 25% NYS tax credit is still capped at $5000, so the optimum ‘sizing’ is $20,000 after the NYSERDA credit, so I’m hoping for an 8000 watt system costing ‘only’ $28000, since that would bring the total cost down to exactly $20000 and i’d get the full credit. Doing the AC work myself should lower the cost enough to make this possible
.

What this article is missing is the data behind each individual EV. As all EVs are not the same and an ‘average’ between the three vehicles is useless.

So far we know AAA tested a 2013 Nissan Leaf, a 2012 Mitsubishi i-MiEV, and a 2014 Ford Focus Electric.

Knowing which is best in 75, 95 or 20 degrees would be helpful when shopping for an EV based on your clement.

Yes, the smaller the battery, the larger effects from cold. Chemistry considerations aside, even just considering the proportion of energy consumed to keep the battery and/or passengers warm… this will impact the range of an EV with a smaller battery much more than one with a larger battery.

In a Model S, with its much larger battery, I’m sure the effect is not at all near the AAA “average” of 57%.

Agree …

Were individual results for each EV posted, or just the average of the fleet?

It’s like the saying average US vehicle sold last year attained 24.8 MPG. Meaningless MPG values to both F150 and Prius owners.

Yes . . . not a single person drives this ‘average EV’. Give the data for the individual cars separately.

Ugh, seems like it’s a rotating duty among mainstream bodies in publishing doom-and-gloom EV stories with headlines as eye-popping as possible.

Where are the details on “stop-and-go”? Is it like one’s ordinary urban driving – or more like the Atlanta mega-jam on its snow day this winter?

How much of the battery was drained by heating/cooling while stuck in a jam – and how much because efficiency had really decreased?

Who cares. put that “57%” on top to get some ratings, point out to “additional information” which doesn’t exist on their website to get even more traffic (I checked, no additional information).

Yes, cold weather degrades performance, but 57% sounds like a rigged test to me, and absent additional details that is my working assumption.

They also likely didn’t pre-heat or pre-cool

What car gets 105 miles? A Coda??

Simply not fair of AAA, to take ideal instead of EPA range as the start point. Consumers will now take 57% from the more common EPA value (and be wrong).

Focus Electric owners are pretty consistent about 58-60 mile range at 12 to 20 degrees in Michigan, with heater on low.

Temps over 95 report a -7 range reduction to 72-75 mile range with air set at 70 degrees.

My Volt gets the same numbers as the AAA. 73klm in summer and 33klm in winter, but i’m in Quebec and have to use winter tires. Buyers need to take those numbers as fact to choose the right car for the’re needs.

I wonder what the battery efficiency will be like with the batteries presently in development, [lithium/air/metal]?

I suppose for approx EPA 75 rated range models it’s meaningful to test with city scenario and that is good to know but but not that meaningful for EPA 100+ rated EVs. Once range gets beyond a certain amount a highway driving scenario becomes more important and the values are much less impacted by extreme whether.

Either way, both values (city and highway) should be reported separately to be more useful and representative.

Actually, that’s about right. During the polar vortex, when it was about 4F, my friend drove his Think City really hard to test its range, and I decided to do the same thing in my 2012 Leaf. The only problem is that you can’t separate the temperature effect on the battery directly from the extra energy drain due to climate control (unless you’re willing to drive around in an unheated car at 4F).

I drove at hard highway speeds with the CC set to be a comfortable 76F, seat heating on high and steering wheel heat on. I wanted to get a worse case estimate. My range was just over 40 miles, while under ideal conditions, it’s a comfortable 80.

So, worse case, it’s possible to cut the range in half, but that’s if you’re totally oblivious to your surroundings. With a bit of common sense, you can take a more modest range hit.

I think that, at least for me and my 2012 I-MiEV, the 57% reduction (while using heater)in the coldest weather and city driving is pretty spot on. This winter has been consistently cold, below the usual cold temps we see in Philly. I more or less drove with the heat off almost every day(I NEVER had it running the entire commute)and on the best days I was seeing 50 miles range. In warm weather, pleasant temps, my back road commute was yielding 80+ mile range.
Lou