Consumer Reports - Winter chills limit range of the Tesla Model S electric car

[Hut]

What are the Rated Range under these scenarios?

1. Full Standard Charge for a 85 kwh pack --> 240 miles?
2. Full Range Charge for a 85 kwh pack --> 265 miles?
3. Full Standard Charge for a 60 kwh pack --> 187 miles?
4. Full Range Charge for a 60 kwh pack --> 208 miles?

 

[RDoc]

What are the Rated Range under these scenarios?

1. Full Standard Charge for a 85 kwh pack --> 240 miles?
2. Full Range Charge for a 85 kwh pack --> 265 miles?
3. Full Standard Charge for a 60 kwh pack --> 187 miles?
4. Full Range Charge for a 60 kwh pack --> 208 miles?

It greatly depends on the tires, temperature and if you are using cabin heating, assuming driving on dry roads.

 

[Hut]

It greatly depends on the tires, temperature and if you are using cabin heating, assuming driving on dry roads.

I understand that you may not get the Rated Range.

However, I would like to know what does the meter say after you done a full charge under those scenarios.

 

[vfx]

Hi RDoc. I agree that you don't want to do a lot of range charges. But I still feel that when any source publishes "how far an EV can go" for a long-distance EV (I might agree with you for a limited-range EV like the Leaf), it should include the range number. Just driving around town (when, indeed, they shouldn't do a range charge), nobody cares about the range number, because they're not going to stretch it. When you care is when you are on a road trip, and that is when you do range charge. I don't think (?) anybody was calling for regular range charges; they were just noting that when you care about the top range is for a trip when you will do the range charge.....

Putting it another way.

When doing long drive that is EXACTLY when you do a range charge. Indeed that's why it exists, for those infrequent trips.
Both the NYT and now Consumer Reports have commented on battery degradation by doing a range charge. It may be true but It should be made clear to them it's needed for Supercharger testing.

 

[jerry33]

When doing long drive that is EXACTLY when you do a range charge. Indeed that's why it exists, for those infrequent trips.
Both the NYT and now Consumer Reports have commented on battery degradation by doing a range charge. It may be true but their misplaced caution is excessive.

There are a couple of conditions to be met when writing one of those screen warnings:

1. It has to be short or folks won't read it at all.

2. It has to be strong enough so that it won't be ignored.

Unfortunately, these two requirements means that the uninformed will not use it at all, as opposed to using it when the situation requires but not every day. Probably the best way to address this is to have a "See more" on the warning screen that opens up a full discussion of the effects and when it should and shouldn't be used.

Of course, a complete manual would do the same thing, although I'm given to understand that most people don't read the manual.

 

[Doug_G]

Thanks for the report. I am a bit surprised at that as I would feel comfortable driving 200 miles on a range charge anytime the temp was above 20. And I am in Minnesota. I am eager to get warmer temps this spring so I can test tis out up here.

Heck, I've already driven 190 miles at temperatures as low as 0F. It requires a little care but isn't difficult.

 

[dsm363]

One of the NT Times picks for top comment says a lot about their response to this:

twenty-ninerReal, WorldNYT Pick
Just out of curiosity, did the Consumer Reports article titled "Winter chills limit range of the Tesla Model S electric car" unleash an army of nippy sycophantic attack nerds? Some quotes from the article:

"In the end, I made it with no need for a rescue, rolling on for three miles on empty. All in all, I covered 176 miles during a typical winter day in the Northeast and not too far off the 188-mile range initially projected."

"The "projected" range was even scarier at 15 miles left after cold soaking at 30° F through the night."

"To be clear, cold temperatures, need for cabin heat, and a high portion of freeway driving, which minimizes the opportunity for regenerative braking, are the most adverse conditions for any electric vehicle."

"Any potential EV buyers in the Snow Belt should consider our experience; winter exacts a tough toll on range."

These tend to corroborate Mr. Broder's general experience. L-i battery performance does not degrade linearly as temperatures decline. There is actually a knee curve right around freezing where performance starts to degrade exponentially.

Bottom line, save .75$ on the dollar (and spare your local land fill from being filled with toxic L-i cells) and buy a more thermally-efficient modern diesel, which also happens to be produce less CO2 per kilowatt than a coal/gas power plant charging a giant copper top.

 

[Kevin Sharpe]

What are the Rated Range under these scenarios?

1. Full Standard Charge for a 85 kwh pack --> 240 miles?
2. Full Range Charge for a 85 kwh pack --> 265 miles?
3. Full Standard Charge for a 60 kwh pack --> 187 miles?
4. Full Range Charge for a 60 kwh pack --> 208 miles?

Here the range figures for the 85kWh pack...

 

[brianman]

Kevin, can you provide the specific link rather than just the domain. Thanks.

 

[RDoc]

Heck, I've already driven 190 miles at temperatures as low as 0F. It requires a little care but isn't difficult.

What kinds of speed did you do this at and what did you do for cabin heat?

 

[CapitalistOppressor]

Agreed... they also need so stop talking about 300 miles estimated range because it generates a climate of mistrust IMO.

I've agreed with this statement since the EPA tests came out. The past few days though I've been engaged in trench warfare across the interwebs over the NY Times report, and while slogging through arguments over what happened its become increasingly clear that the Model S might have a fairly substantial reserve once you hit zero.

I actually want to start a thread on this issue when I get home this evening and can search for the one or two other instances where folks have driven the car till it just stopped. In the cold it looks like Broder might have driven ~20 miles after reaching zero. If true (I need to review the graphs), that's not nothing and it gets a 265 mile car a lot closer to being a 300 mile car. Sure, it's highly inadvisable to access that power, but it would be interesting to know how much is there in an emergency.

 

[Lunar]

I actually find this article a bit annoying. Yes, it is mostly positive and definitely attempts to be factual but there are relatively serious errors and certain points of emphasis that reflect badly on the car. First, the headline is negative:

Winter chills limit range of the Tesla Model S electric car.

A truer headline would be "Winter Chills Barely Effect Range of Tesla EV" Unfortunately a headline is often the only thing most people see in an article. This one just makes everyone go - "Oh, the NYT article must be right." Also, I can't believe that a car editor does not understand he needs to charge fully before making any long distance road trip. How many more times will this crucial mistake happen? It is the only reason the car range fell anywhere near 0 in the first place but most people won't understand that. Nor will they understand that it was wrong to compare the milage the reporter got with the EPA rating since that EPA rating is based on maximum charging. So, because he got that lower milage figure, he felt okay using the negative headline figuring the difference was because of the temperature but of course that was not true. I believe it is an honest mistake but extremely unfair to Tesla and really needs to be corrected since it creates a negative take-away for the casual reader that is simply false. I hope it is clear to everyone here that the warning on max charging is only meant to discourage doing it everyday - not to keep people from doing it ever. The car is designed to be charged fully when taking a long trip which just doesn't happen that often for most families.

 

[Doug_G]

What kinds of speed did you do this at and what did you do for cabin heat?

I use the Range Mode heat. It doesn't affect your range by much, and is quite comfortable. I'd rather slow down a little than turn the heat off!

Speed depends on conditions. On one trip I was doing 50 mph but that because of horrible road conditions and traffic! Usually I do 55 to 60.

On my last trip I was doing 67 at 3 degrees F, while drafting a truck (about a second behind), and was actually getting Rated Range!

(Units all converted to American-ese for your convenience.)

What I do in practice is drive for a while, look at how my Projected Range is stacking up, and adjust my speed to maintain a 20 mile reserve.

 

[100thMonkey]

Honestly I'm a bit surprised that folks feel so positive about this article. I've been a customer of Consumer reports for many years and I expect better.

-the guy violated rule number one in the owners manual for standard operating procedure by not plugging in over night, it's in bold print. this is a good test to see what people can expect on overnight trips, but when trying to test the everyday range, it produces a misleading number.

-Aside from not getting a full charge, not plugging in left the battery much colder than it would have been in day to day use, charging in accordance to the manual.

-his assessment of total range is rather bogus. it's no small mistake to refer to the EPA rating and not start with a "Max Range" charge. given the weight of Consumer Reports opinion for a lot of people, they really shouldn't be this sloppy!

-The whole bit about improving range by braking more and thus somehow generating more energy is so off the wall it suggests this guy truly has little understanding about what he is doing.

- To test the car's max range, it seems only logical to not only give in a "max range" charge, but to also adjust the settings to "Range Mode". A "max range" charge and "Range Mode" are two different things! Range mode is designed to maximize range regardless of state of charge and from what I can tell so far, combined with a few other adjustments can make a substantial improvement in range, depending on just how cold it is outside.

- Ev's are made with a prewarming capacity specifically to minimize energy use and extend range. I've found using range mode and setting the thermostat to 71 and putting the climate control mode to defog (with power defrost off) and leaving the fan on lowish makes for an enjoyable and long range ride with little to no fog on the windshield, assuming I first start with prewarming the car. This is such an improvement over our Nissan Leaf, I see it as no small achievement.

it's clear to me that Tesla needs to improve the manual with a section specifically for getting the best range in cold weather, perhaps even include such a run down on a brightly colored piece of paper that goes at the top of the stack of manuals in the glove box and is gone over during orientation. Ev's, even the Tesla S, require some adjustment in use patterns as compared to ICE vehicles to utilize their full capacity. If these adjustments are made stupidly clear in a neat summary, the folks doing the reviews are going to continue to fumble and miss the opportunity to realize and convey the car's true potential.

 

[CapitalistOppressor]

Honestly I'm a bit surprised that folks feel so positive about this article. I've been a customer of Consumer reports for many years and I expect better.

-the guy violated rule number one in the owners manual for standard operating procedure by not plugging in over night, it's in bold print. this is a good test to see what people can expect on overnight trips, but when trying to test the everyday range, it produces a misleading number.

-Aside from not getting a full charge, not plugging in left the battery much colder than it would have been in day to day use, charging in accordance to the manual.

-his assessment of total range is rather bogus. it's no small mistake to refer to the EPA rating and not start with a "Max Range" charge. given the weight of Consumer Reports opinion for a lot of people, they really shouldn't be this sloppy!

-The whole bit about improving range by braking more and thus somehow generating more energy is so off the wall it suggests this guy truly has little understanding about what he is doing.

- To test the car's max range, it seems only logical to not only give in a "max range" charge, but to also adjust the settings to "Range Mode". A "max range" charge and "Range Mode" are two different things! Range mode is designed to maximize range regardless of state of charge and from what I can tell so far, combined with a few other adjustments can make a substantial improvement in range, depending on just how cold it is outside.

- Ev's are made with a prewarming capacity specifically to minimize energy use and extend range. I've found using range mode and setting the thermostat to 71 and putting the climate control mode to defog (with power defrost off) and leaving the fan on lowish makes for an enjoyable and long range ride with little to no fog on the windshield, assuming I first start with prewarming the car. This is such an improvement over our Nissan Leaf, I see it as no small achievement.

it's clear to me that Tesla needs to improve the manual with a section specifically for getting the best range in cold weather, perhaps even include such a run down on a brightly colored piece of paper that goes at the top of the stack of manuals in the glove box and is gone over during orientation. Ev's, even the Tesla S, require some adjustment in use patterns as compared to ICE vehicles to utilize their full capacity. If these adjustments are made stupidly clear in a neat summary, the folks doing the reviews are going to continue to fumble and miss the opportunity to realize and convey the car's true potential.

I agree that its not a perfect article. But he was pretty clear that he was simulating a short (~90 mile) trip out of town, in the cold, to a location that didn't have a charging station. In fact, its pretty obvious he structured the entire article to address the bogus NY Times article. The bottom line in his testing is that a full standard charge (which he explains, while contrasting it to a range charge) would allow the car to travel ~180 miles despite an overnight stay (in the cold) without access to an outlet.

Consider: Broder states that he left Milford with 185 "rated" miles, stayed at a hotel overnight, and failed to make it back to Milford while describing all of the stupid things he did to try to mitigate his problem (whether advised by Tesla or not, they were stupid). Consumer Reports went through the trouble to simulate that trip, and then explained how the overnight range loss is partly illusory and how you should just drive through it.

Consumer Reports even made the effort to debunk the use of "Rated Range" that Broder relies upon, and gives an extensive discussion about how accurate "Projected" range was in this circumstance. This article was a head to toes takedown of Broder.

Sure, there are nits, and Consumer Reports certainly isn't representative of the state of the art when it comes to cold weather driving in the Model S, but their review clearly demonstrates how the Model S actually performs on the trip that Broder failed at. I'd suggest sending them a note with your observations so they can attempt to improve upon their performance. Frankly, from what I've read they are one of the few media organizations which made a real attempt to refute Broder and establish a realistic baseline for the particular conditions that Broder screwed up with.

 

[Andrew Wolfe]

I think that the "regen" issue, both in this article and in the NYT article where the guy thought it was a good idea to do some stop and start driving, highlights a difference between the Model S and other electric cars.

Most electric cars (especially the Leaf and to some extent the Roadster) use much less energy/mile on city streets than at 65MPH. The Model S does not - it uses a lot more.

Obviously, this not due to regen magic, but the combination of very high efficiency at low speeds plus good regen efficiency. For some reason, the Model S is different. I would postulate that it is because of the very high mass and the large amount of energy it takes to get moving.

In a Leaf, if I have been driving at 65 and think I have 10 miles left, I can pull off onto an urban surface street, with lights and stop signs, and turn that into 15 miles of range. In a Model S, it turns into 7 or 8. I don't think journalists understand that yet.

 

[TonyWilliams]

I think that the "regen" issue, both in this article and in the NYT article where the guy thought it was a good idea to do some stop and start driving, highlights a difference between the Model S and other electric cars.

Most electric cars (especially the Leaf and to some extent the Roadster) use much less energy/mile on city streets than at 65MPH. The Model S does not - it uses a lot more.

Obviously, this not due to regen magic, but the combination of very high efficiency at low speeds plus good regen efficiency. For some reason, the Model S is different. I would postulate that it is because of the very high mass and the large amount of energy it takes to get moving.

In a Leaf, if I have been driving at 65 and think I have 10 miles left, I can pull off onto an urban surface street, with lights and stop signs, and turn that into 15 miles of range. In a Model S, it turns into 7 or 8. I don't think journalists understand that yet.

The Rav4, at over 4000 pounds, does significantly better on the freeway at 65mph than around town.

In the LEAF, I could easily match the 4 miles per kWh (250w per mile) at 65mph (without a heater) on nice days that I could also do around town. On the Rav4, it's not even close; I average 2.7 (370w per mile) around town and 3.4 (295w per mile), again, without heater on nice days at 65mph.

 

[ElSupreme]

I tried to register on Consumer News so I could post the following, but the confirmation email never got through to my inbox. I went through the process twice and tried two different email addresses: no dice. So if someone who has registered successfully wants to post my comments (or your version of them), feel free...

"Those of us who have been driving a Model S through the winter (I live in Colorado) applaud you for ‘telling it like it is’ without undue drama. Winter driving takes a toll on range for all vehicles, a toll that we often overlook when driving gas-powered cars with their imprecise, analog fuel gauges (and with a gas station on every corner).

A couple of observations: almost all of the loss of range at highway speeds is due to increased aerodynamic resistance, which increases as the square of velocity. Regenerative braking has nothing to do with it, as you implied in the article; in fact, hypermilers go out of their way to avoid regenerative braking because all regen can do is recapture a portion of the car’s kinetic energy, energy that was expended from the battery to get up to speed in the first place. Regen braking is a good thing, because otherwise you’d be throwing away all that energy in the form of heat generated by using the normal friction brakes, instead of putting some of it back in the battery pack; but it’s no perpetual motion machine."

I had this problem also. I had to try to sign in and fail. They give you a link to 'resend' your login information. Then you will get the email. But wait, there is more. The link they give you will be broken, you have to copy and paste the url into a browser. Then you are free to login and post your response.

Looking it appears that my post made it out of moderation so you might actually get up there.

 

[jcstp]

I read the answers!
You guys did a great job!
Even a uneducated person could understand it all!

I am curious if they will do a 2nd test, applying the hints of their readers (commentators!) ;-)

 

[aaronw]

Actually the power to maintain speed is based on the cube of the speed so it's even worse.

From http://en.wikipedia.org/wiki/Drag_(physics)#Power