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Tesla Model S range reduction due to cold weather (An Informal Study)

We have a lot of people reporting, on numerous threads, that the Model S has range reduction issues in cold weather. I would like to collect some data to determine, in the real world, how the Model S performance fairs at different temperatures. To do this I need data (from you). If people with a dedicated electric meter can post power usage information I would be happy to crunch the numbers and maybe we could determine some real world information about this issue.

I would like to determine 1) power overhead to run the car. i.e. the Model S reports how many KWh it consumes when "on", but doesn't report how many KWh when it is "off", 2) Estimates of wh/m while driving. and 3) Charging efficiency. I would like to determine all three of these as a function of temperature. If this thread decides to try to derive additional results I will be happy to add them to this list.

What I would like people to post is. 1) Time covered by your report (in hours). The period reported should start and end with the car fully charged (either standard or max range setting). 2) Miles/KM driven. Please specify units. 0 means you were just charging for the time covered. 3) Power consumed as indicated by your dedicated utility meter, for the time covered (i.e. end meter reading - start meter reading). 4) What Model S said it consumed for the time covered (You might consider using the A or B trip meter. and 5) You best guess of what the average temperature was for the time covered. 6) Anything else you think is important.

Ideally I would like this study to last for 1 year (that may be asking to much.... but I can ask).

I will set up a public spread sheet to allow all of us a chance to review and comment on the analysis of the data.

You'll need cabin temp for a complete picture.

Where your lights on?
When started was the power limiting bar displayed on your clock?
Was the regen limiting bar displayed?
Was the cabin brought up to temp before you set out(unplug)?
Asking for science of course.

maybe ask Tesla for the logs of the test cars?

-28C is damn cold. Not sure what I would expect there, but it was probably struggling to stay warm.

@nickniketown - since you decided not to buy a car, whose experience are you reporting? Does he work for the NYT? :)

@nickniketown, You've noted repeatedly in other threads that you don't have a Model S...are you just taking a guess, or mocking the original question??

nn;
please try to get out of SMS mode when posting here.

Thought this was appropriate to repost here. Hope it's okay with theaustin...

TheAustin | FEBRUARY 16, 2013 NEW
I took a drive into New York City from the Hamptons a few weeks ago, a trip that is almost exactly 100 miles...In weather that was cold and windy in the mid-20's, I used 130 miles of Rated Range to go 100 miles (almost identical results there and back, and I had a passenger on the way back).

Earlier this week I replicated that same trip, although the weather was in the mid 40's...My actual mileage was pretty much exactly 1:1 with my Rated Range, which made me very happy. I assumed that Rated Range was going to be over-estimated, but in certain conditions, it ends up being a very realistic real-world estimate.

FYI, for 75% of the drive both times, I had the car on cruise control at 65 mph, had the heating set between 70-72, and used the seat warmer for part of the time, and had the radio on the whole time (And, did not have the car operating in Range Mode).

The difference in mileage on the colder drive appears to be pretty consistent with then 25% cold weather range loss figures quoted, and I'm OK with that. And I'm glad that I now have an idea of what my car can do in ideal conditions, and less than ideal conditions..

@BrianN, nn doesn't have a non-SMS mode!

I have the same observation with my model s 85, in the -20c weeks in Montreal.

I did a 38 mile(each way so 76 total) overnight trip a few weeks back at an average of 34 deg F with no overnight charge. I started with 242 rated range and when I got back I had 142 miles of rated range.. And I drove pretty aggressively; and when at highway speeds I was generally doing somewhere between 60-75. I didn't pay attention to Wh/mi usage. But this suggests somewhere on the order of a 20% reduction due to cold weather, no? I guess it's hard to nail down what component was due to driving and what to weather though. Oh and no wind and 21" wheels, cabin was at 70 and DRL were on.

Brian H - i don't think it's an SMS issue with nn, I think ESL is the TLA (three letter acronym) that may apply here.

I'm not sure nn. I think we'd need many more data points to answer that question. But I assume that's what the original poster dtesla is trying to do!

I'm configuring my MS & looking for some suggestions. Hopefully I'm in an appropriate area on the forum. I'm in Southern Ohio where we get a few extremely cold days but normal winter weather is in the 20-35F range. There aren't any super-charger stations around here and probably won't be for the foreseeable future. Occasionally I'll be charging away but most of the time at home. I plan on having a 240v line installed in my garage. Would I be gaining anything by configuring with the dual charger?

A second question I have is in regard to tires. I'm ordering the car with the (standard) 19" all weather tires and am wondering how satisfactory they are for the colder weather. Would it be advantageous to also spring for a set of winter tires? Snow is not a huge problem in that we get a good blast only a few days each year.

Thanks for any tips!

@bottesini - the only thing dual chargers gives you is the ability to charge up to twice as fast as a "regular" NEMA 14-50 240V/40A outlet. To do this you'll either need to buy an HPWC, or find a public J1772 outlet that supports 70 or 80A.

So...if you can think of a situation where either (a) you come home with an empty battery and need to charge quicker than 20 mph, or you think you will have access to 70A J1772 outlets and care about charging faster than otherwise, then yes, dual chargers make sense. If you plan to recharge overnight, and maybe at work, then dual chargers don't make sense.

I'm in Florida, so I'll leave others to answer the tire question.

It seems a bit strange to me that @nickniketown has never mentioned in any other thread that he has a family member who owns a Tesla. He recently showed up and only has negative things to say. I firmly believe he is simply here to get his kicks or get some quotes for his next article.

For 2000 or so miles I have averaged 400 KWh/mile in temperatures hovering about 32F, mostly 70mph driving with heat at 72, radio on, lights on, one passenger, moderately hilly terrain. Now that it's up to 45-50 degrees, it seems like I'm closer to 350 KWh/mile for the same trip. There are some shorter around town trips thrown in, but I'm not sure those are any easier on the battery since younare constantly re-heating the batteries.

sancann;
to be fair, nn has mentioned his brother several times. He has problems maneuvering far out of Quebec City with it. Maybe now the Sun Country Highways 90A system runs across the country he'll {selfsnip}.

I just took my 60kWh car on a 182 mile trip to do some wine tasting in Hermann, MO. I started the trip with 197 rated miles. The car was still charging to max range when I unplugged it. The interior was preheated to 68F (my preferred temp). It was 10am when we left. I had limited regen because the charge was so high. My wife and I both used the heated seats at setting one.

The first 40 minutes, ~36 miles was to my in-laws. It was mainly highway at 65mph hilly at the end. I used cruise control the whole way. The last 5 miles of that trip I had a 298 average watt/mile. I was impressed.

The next ~20 miles was driving my in-laws up to a local RV camp store where they said I could get an adapter to go from their TT-30 to my 14-50 so I could charge at their house if needed. (it didn't work)
Speeds were between 40-65mph with a few lights. I did floor it once to show them the acceleration. The aggressive driving and stop and go pushed my average w/m to 344.
We left here at 1:30pm

After that it was 45 miles to Hermann. My wife's feet were cold because she talked with her step-mom outside while her dad and I played with the adapter for an hour trying to figure out why it wouldn't work.... so she cranked her heat up to 74.
5 miles of this trip was at 70mph. The rest on Highway 100 was ~60mph.
We arrived in Hermann, MO with 80 miles of rated range left. From here we parked and walked the strip sampling wines and beer for about an hour or so. It was 2:30ish pm when we parked.

At 3:30 I noticed the battery was getting cold because when I check on the car thru the app it was at 76 miles. When we finished up our beers we went to a winery which was a few miles away. It was very close (a short walk up a hill) to an RV campground. I plugged into a 14-50 and started charging at 4pm.
I unplugged at 4:53pm with 101 rated miles. Temps outside had dropped to 32F. I drove a few miles thru town back to a restaurant for dinner. The car sat unplugged until 6:30pm when we headed straight home in 28-30F temps. Heat set to 70 and seats on setting 1. I forgot to note the rated miles when we left.
The total distance back home was was about 76 miles.
40 miles around 60mph.
36 miles around 70mph.
The car reduced my power somewhere are 15 rated miles but I was very close to home at this point.
When I shut the car off at 11 rated miles the car instructed me to plug in.

My total average watt/mile for this trip was 344.
I used a total of 62.7kWh.

I never had any range anxiety because I knew there were dozens of RV campgrounds along the entire drive.

Hope this helps.

Thanks Sudre_

@Oliver - worse than reheating the batteries, you are reheating the cabin. When I was on an out-of-town trip where it was below freezing the whole time, I made lots of 1-5mi trips and my energy use was around 900Wh/mi, just because the heater was running full blast all the time.

@HH - having it not plugged in overnight means you are losing 100W or so from keeping the electronics running, plus whatever it had to use to keep the battery warm.

@jat - I think there is a very large amount of fresh air circulation (anyone know if recirculating the air on a cold day improves range?). Just turn on the heat with the remote app and stand outside the car door, and you will be met with a blast of warm air. I suspect this continues at speed. The Model S may be a bit more 'perforated' than some vehicles. I do notice influx of cold air at odd times (for example, when I am passing a bus or truck, in a severe cross wind) that I haven't seen in other cars. That's why I made the assumption that it's more heating the batteries than the cabin, but it's likely a bit of both.

O

@Oliver - on the other hand, once it's warm the fan turns down and so presumably the 'lost' warm air is also reduced. Certainly it's true that the fan speed goes down once it's warmed up. This may explain why 'Range Mode' has slower fan speed as well.

Oliver;
recirculating the air on a cold day will fog/frost your windows, since the humidity inside will spike. Warmed outside air gets very dry, which is best for clear windows. Though it may may your skin crinkly!

The heat load for warming the cabin air isn't much, but the air must gradually warm up all the surfaces it's touching, too. Which cools it back down, etc.

Here's my cold story from yesterday. Car is in a garage overnight and it was WINDY on Sunday night in NY. Woke up to 15oF outside.

Full charged at 7am (standard charge) - 234 miles (vs 240 when around 30oF outside)

Drove 55 miles at 80mph with comfortable heat setting inside (71oF) - 143 miles when i arrived (now 8am). 91 rated miles used.

Got in car at 5.30pm (parked outside now 30oC) - rated range is 113. Lost 30 miles of range (probably 8-10 from normal sitting unplugged all day and 20 from cold)

Drove home 55miles at 80mph and had 65 rated range left upon arrival. Regen took a good 15 mins to kick in but only used 48 rated miles to go 55 actual so got some of the "lost miles" back.

All in all, I used 139 rated miles to go 110 actual miles and sit all day with fast (not aggressive!) driving style.

It's so fun to drive.

I hate reporting other people's comments, but this thread is a great place to consolidate related info...

I was at the Milford supercharger today and they were setting up for the shoot. Looks like they finished up and documented another failure to reproduce Broder's problems:

http://search.cnbc.com/main.do?target=all&categories=exclude&keywords=tesla

This was the most balanced report I have seen yet.

I took my 60 kWh from Northern NJ to central Connecticut and back in 40ish degree weather no problem. The supercharger was terrific for topping off. A few observations:

Using eco mode on the climate control, and cruise control at 70, the range was exactly predicted by my rated range. Very accurate.

Coming back using non eco mode, driving without cruise control, going 70-75, the range was 80% of rated range.

Supercharger data on a 60 kWh vehicle: 326 V, 60 kW, 185 A.

This car is just terrific. It was a pleasure to take it on its first road trip, and I had no range anxiety. I got a special laugh out of the BMW passenger taking video of the MS on I-95.

You beat me to it!

Some data (rough -- I'll post more exact numbers as the weeks progress, if that helps):

I've had my 60kwh Model S for two weeks. I live in Chicago, where it's been around 9 to 30 deg F. I charge it up to around 180 miles of rated range on standard charge (out of the 230 if I did it at max range) every night, in a cold garage, so I start my day at around 176-183 depending (not sure if the fluctuation is due to the cold or not). I drive approx. 20 miles to work, and when I park in my garage my rated range is between 146 and 152. I drive another 20 home, and by the time I park back in my garage I'm around 110-115. So I'm obviously depleting more than the 20 miles of charge per trip, but I can't (yet) determine if this is due to the cold weather, or how I drive (I like getting the car up to around 80mph on the highway, and I have the heat on 70-72 deg F, and the music blaring...). My % of miles driven to miles depleted is on average 60%.

Long way of saying: the range is not entirely 'accurate,' but I'm not disappointed, either -- sort of like having an ICE rated at 25mpg and being surprised at getting only 18mpg (which was what my old BMW did, the way I drove it). I'll see how this ratio is in warmer weather -- maybe I'll only deplete 25 miles for every 20 I drive, instead of the 30-35 I've been depleting so far. Regardless, the car is amazing, fantastic, and a pure joy to drive.

Once, you drove to live. Now, ...

@Brian H: Just to be clear, there seems to be a higher rate of air exchange in the Model S than I have experienced in other vehicles (although vehicles I have owned have been exclusively German, with the exception of the smart, which is a French car made by Germans). The doors appear to allow considerable flow of air outward, and there is considerable variability in air entering the vehicle depending on the microenvironment around the car.

As such, I suspect that the effect of turning down the fan has less to do with saving energy from the fan itself, and more due to having to heat less air that is just going to flow out through the doors. That being the case, as well as the fact that it takes time to heat the surfaces, it does seem like it would be more helpful to be able to turn on the seat heaters and defrost prior to entering the car via the app. Hopefully this is in the works (although if they wait much longer, maybe they could just as well wait until the fall...)

One other thing to note on the cold weather range, I have noticed a significant improvement in energy utilization after about 2000 miles. This may be driver related, as I learn how to manage the energy use, or weather related (we had a cold January in Seattle) but I also do believe there is some break-in period that may improve the efficiency as well. So Kudos to Consumer Report to allow the car to break in prior to testing....

O

First, thanks for everyone's support. I'm glad to get the feedback from everyone.

Last week (2 hours short of 7 days to be exact) I drove my MS 254 miles. My power meter said I used 111 gross KWh, while the MS reported 82 net KWh used. The average temperature was 35F.

I like reading the details about your trips. So I'm not asking you to stop. I just want everyone to realize that I'm a volunteer and I won't spend the time to figure how to get all of your details into a spreadsheet. Just trying to set some expectations on what the results will look like.

Many posts talk about expected verses actual range. Does the thread what the experience is different then what the Go Electric page predicts? is this something we should track? Personally I think when I turn the heater, etc. on the predicted range should change.


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