Winter Driving Experiences

[Doug_G]

I live north of Toronto, where we get more snow and colder weather than the city, so I have been following this thread with great interest. We also have a significant hill which is often unplowed when I have to drive to work. I have had the Model S out a few times in snow and have not, to date, been able to replicate the problems reported by some of the contributors to this thread.

When it happened to me, the two things that appeared to be required to get "stuck" were (a) worst-case slippery, and (b) car was completely stopped. At that point the TC was holding back the torque so much that the wheels didn't turn at all. To escape the situation I backed the car up until the rear wheels were on something not quite as slippery, and I managed to get it going forward at a couple of kph. The car then was able to slowly carry through. It didn't accelerate in the slightest, but it kept going.

So your hill might not be an issue unless you somehow got stopped in the middle of it. It would also have to be "worst-case slippery".

I haven't encounter any fogging up or icing up problems, but usually drive the car solo and have pre-heated the interior (while on charge) which together with a high fan speed bringing in outside air likely helps to avoid such problems. The energy consumption on the road is also significantly higher in winter (which I had expected from my experience with Prius'). When I tried to minimize energy consumption, driving about 80 km/hr in range mode, I managed to get the consumption down to about 200 W/hr per km, but after 40 or 50 km I received a cold battery pack warning, even though the outside air temperature was only a few degrees below freezing and the battery still had close to 300 km of range left? Does anyone know the implications of that warming? I arrived home shortly after receiving the warning, put the car on charge and all seems to be fine, but the warning seemed to be a cause for some concern (especially in view of the relatively warm temperature and short duration of the trip).

If you start driving with a cold pack then the car heats it, wasting lots of power, to bring it up to operating temperature so the efficiency will improve. This usually works well but can have an undesired result with the wrong "trip profile". One day I did a series of very short trips, with long stops in-between, and the consumption was ridiculously high. That's because I did a series of short trips of 2-3 km, parking in the cold unplugged for 2-3 hours between each trip (Christmas shopping anyone?). So the entire day was spent heating the pack and freezing it again. My consumption was close to 500 Wh/km that day. But I didn't travel very far so it didn't matter - I had lots of range left.

That said, my average consumption is 245 Wh/km (I've yet to reset Trip B). I've done a couple of road trips now, and I'm able to maintain much lower power consumption on the highway.

I agree that highway driving does NOT result in a warm pack. I get the "pack is cold" message even after driving for several hours at highway speeds. I believe the large surface area on the bottom of the pack results in cooling beyond what the car actually needs. That said, I was getting reasonable range so it wasn't wasting a lot of energy heating.

 

[Zas]

That said, my average consumption is 245 Wh/km (I've yet to reset Trip B). I've done a couple of road trips now, and I'm able to maintain much lower power consumption on the highway.

Thats pretty good.. i am averaging about 343 Wh/km since i got my car - but ALL my driving has been city driving ( short range - less than 20km per drive ) - with NO long drives at all.. nothing over 30km on a single trip yet - so that explains why my average is high.. as once i do some long driving trips the average will drop down..

 

[PatP]

*** IMPORTANT UPDATE - Nokian Hakkapeliitta R (studless) have been installed on my Model S ****

Today, I went to the tireshop to replace my Tesla's RECOMMENDED and TESTED winter tires:
"Outfit your Model S with 19" standard Tesla wheels, Pirelli winter-rated tires, and tire pressure sensors for the icy months ahead." - Pirelli Winter Wheel and Tire Set Tesla Motors

with

Nokian Hakkapeliitta R (studless) (yeah... $1500 on top of what Tesla sold me last week...)

First thing I realize when driving the car after leaving the tire shop is that the car feels different (less sporty, direction feels rubberish). For me it's a good sign as good winter tires always have this feeling. So, I drive for 10 minutes on the highway, car seems to have more traction but difficult to tell if this is not the placebo effect

So, I go to the same two places I went yesterday. Weather is a similar, maybe little bit colder. So, I try the first "Promenade street" test. I make sure my right-side wheels are stuck in the snow. I accelerate slowly.... crossing my fingers that my 130K$ car can be used during the 4 months of winter we have.... Guess what? The car moves forward slowly but surely! Must be to good to be true. I have to make another test...

So next, I go to the unplowed snowy school driveway (test #2). I accelerate , wheels are spinning a little bit. Car is stuck. I back-up the car just a little bit. I press the accelerator again... the car moves forward! I'm so happy!

My initial conclusion is that the recommended and tested snow tires from Tesla are just pure %&$# on Model S. My feeling is that they choose these tires as they maybe more rigid and cope better with regen. I think they made a huge mistake. Actually Tesla almost discourage you to use anything else on the car as this has not been tested...

So, I have to say that - so far - it seems Model S with the Nokian's R is performing well in the snow / ice. I will have to test in the next snowstorm on more difficult hills, but so far this is positive. I will still trade my S for AWD the day it will be become available tough. Our friends in California needs to put some real serious cold test procedures in place. I see at least 4-5 different things that should be implemented to make the car perform better in the snow. Hope Tesla will listen.

Thank you to those who encouraged me to continue posting my tests...

Happy new year!

PatP

 

[Zas]

So, I go to the same two places I went yesterday. Weather is a similar, maybe little bit colder. So, I try the first "Promenade street" test. I make sure my right-side wheels are stuck in the snow. I accelerate slowly.... crossing my fingers that my 130K$ car can be used during the 4 months of winter we have.... Guess what? The car moves forward slowly but surely! Must be to good to be true. I have to make another test...

So next, I go to the unplowed snowy school driveway (test #2). I accelerate , wheels are spinning a little bit. Car is stuck. I back-up the car just a little bit. I press the accelerator again... the car moves forward! I'm so happy!

Excellent News !.. very happy for you to find the right tires for your environment... just a question was TC ON on these tests ?.. as you mentioned your tires were spinning in the school, so that makes me think your TC was OFF ?

Also on normal roads ( no snow at all ) how was the performance vs. the Pirelli's ?

 

[PatP]

Excellent News !.. very happy for you to find the right tires for your environment... just a question was TC ON on these tests ?.. as you mentioned your tires were spinning in the school, so that makes me think your TC was OFF ?

Also on normal roads ( no snow at all ) how was the performance vs. the Pirelli's ?

Night and day. For me, now that I can compare, the Pirelli's are not acting like snow tires - they feel more all-seasons.

Yes, TC was ON. I really think removing TC is a bad idea and could even be dangerous with such a car.

 

[kevincwelch]

Would you mind posting the specs on the Nokian Hakkapeliitta R, where you got them and the price? Thanks.

 

[Zas]

Night and day. For me, now that I can compare, the Pirelli's are not acting like snow tires - they feel more all-seasons.

Yes, TC was ON. I really think removing TC is a bad idea and could even be dangerous with such a car.

Great.. keep giving us feedback on the tires.. this post will surely help those whom were worried about the car in the winter.

 

[Al Sherman]

That post is gonna sell a lot of Happa R's. You DID start from a complete stop on the hill as in the Pirelli test?

 

[PatP]

Would you mind posting the specs on the Nokian Hakkapeliitta R, where you got them and the price? Thanks.

Nokian Hakkapeliitta R - 245/45R19

Bought them from a local tire shop at around $1500 CAN.

- - - Updated - - -

That post is gonna sell a lot of Happa R's. You DID start from a complete stop on the hill as in the Pirelli test?

Yes, stopped in the middle of the hill.

Here's the video with the Nokian tires (there's less snow than yesterday but I feel positive):

Tesla Model S in the snow - Nokian Tires - Promenade Street.MOV - http://youtu.be/Zc1pJl9rj9Y

 

[mknox]

I agree that highway driving does NOT result in a warm pack. I get the "pack is cold" message even after driving for several hours at highway speeds. I believe the large surface area on the bottom of the pack results in cooling beyond what the car actually needs. That said, I was getting reasonable range so it wasn't wasting a lot of energy heating.

Doug, how big a problem (if at all) do you see this being? Although based on my delivery this won't be a problem until next winter, one of my drive scenarios is an approx. 125 mile / 200 km (one way) trip north of Toronto to the cottage. This is mostly freeway and it can get quite cold. What if the "Pack is Cold" message comes on 1 hour into the 3 hour trip? Can I keep driving? While very rare, I have seen it as cold as -40* overnight in the winter. Will a 120v supply suffice in keeping the pack warm enough?

 

[jkirkebo]

My initial conclusion is that the recommended and tested snow tires from Tesla are just pure %&$# on Model S. My feeling is that they choose these tires as they maybe more rigid and cope better with regen. I think they made a huge mistake. Actually Tesla almost discourage you to use anything else on the car as this has not been tested...

Well, they're better deliver something else here in Scandinavia. I read a test about the Pirellis, they got very high marks for performance on dry and wet roads. On snow they were considered well below average and on ice they got the worst result of all. These are tires for people living where you get snow only occasionally and who wants good dry/wet performance all year.

Tesla should IMHO offer both options, and explain the difference between them.

 

[PatP]

Doug, how big a problem (if at all) do you see this being? Although based on my delivery this won't be a problem until next winter, one of my drive scenarios is an approx. 125 mile / 200 km (one way) trip north of Toronto to the cottage. This is mostly freeway and it can get quite cold. What if the "Pack is Cold" message comes on 1 hour into the 3 hour trip? Can I keep driving? While very rare, I have seen it as cold as -40* overnight in the winter. Will a 120v supply suffice in keeping the pack warm enough?

I did Montreal-Quebec (about 240 km) with a full charge in range mode and arrived with 17 km left... Was not driving super efficiently due to snow storm and max heat due to fogging. But it was 0C.

It seems the battery pack is designed to stay cool but it's an issue in cold climate. The Roadster was a big block so much more difficult to get cold.

 

[Jeeps17]

PatP,

Thanks for the update! The Hakka R's are the tires I had planned on getting (with the Tesla rims and TPMS bought separately). I had them on an XC70, and really liked their performance.

Quick question, do you still have sandbags in your trunk, or were your tests done "stock"?

Also, have you had fogging / frosting issues with the colder temperatures?

Keep up the good "work"!

 

[PatP]

Well, they're better deliver something else here in Scandinavia. I read a test about the Pirellis, they got very high marks for performance on dry and wet roads. On snow they were considered well below average and on ice they got the worst result of all. These are tires for people living where you get snow only occasionally and who wants good dry/wet performance all year.

Tesla should IMHO offer both options, and explain the difference between them.

Totally agree... Tesla saying: "Pirelli winter-rated tires for the icy months ahead." is not very exact to say the least.... This is what happens when you live in California.....

- - - Updated - - -

PatP,

Thanks for the update! The Hakka R's are the tires I had planned on getting (with the Tesla rims and TPMS bought separately). I had them on an XC70, and really liked their performance.

Quick question, do you still have sandbags in your trunk, or were your tests done "stock"?

Also, have you had fogging / frosting issues with the colder temperatures?

Keep up the good "work"!

Yes, I still have sand bags (but only 4 X 60 pounds) in the trunk. I wanted to have the same conditions as yesterday. I will remove them today for my upcoming tests. Yes, fogging is still an issue. The only way not to have any fog, is manual mode, full blast heat, windshield only. which is not convenient. they need to change their auto mode to account low temperatures. also, it's weird that fogging is only happening on driver's side even with 4 person in the car. My guess is that the blower / heater is on the passenger side - sigh....

 

[mknox]

I did Montreal-Quebec (about 240 km) with a full charge in range mode and arrived with 17 km left... Was not driving super efficiently due to snow storm and max heat due to fogging. But it was 0C.

It seems the battery pack is designed to stay cool but it's an issue in cold climate. The Roadster was a big block so much more difficult to get cold.

Thanks. Did you get the "Pack is Cold" alert on this trip? Just trying to get a handle on what you're supposed to do if this message comes up mid-trip.

 

[PatP]

No, but temperature never went below 0C. Also, I think the "pack cold" alert is new with firmware 4.1 (which I didn't have then). I'm pretty sure you can still drive when you get this message - it's just that your range will be less and probably the batteries can't discharge as quickly so less performance (but we don't care about performance during winter time!)

Maybe Doug could confirm?

 

[Doug_G]

Doug, how big a problem (if at all) do you see this being? Although based on my delivery this won't be a problem until next winter, one of my drive scenarios is an approx. 125 mile / 200 km (one way) trip north of Toronto to the cottage. This is mostly freeway and it can get quite cold. What if the "Pack is Cold" message comes on 1 hour into the 3 hour trip? Can I keep driving? While very rare, I have seen it as cold as -40* overnight in the winter. Will a 120v supply suffice in keeping the pack warm enough?

Sorry, I guess I wasn't clear. You only get the message when you park the car. It drove completely normally for 300 km and gave me the message when I parked it. I guess the pack temperature was a little lower than the control system liked, but it was 100% working normally.

 

[stopcrazypp]

I don't know about this explanation. Generally what people do to get better traction is add weight to a car such as a few hundred pounds of sand over the rear wheels. The physics is that the force is a function of the coefficient of friction times the weight, so more weight gives more force.

If there really were so little friction that the car couldn't move uphill at all, it would slide downhill when stopped, a very scary situation I've been in and do not recommend.

I don't know the relative contributions of each but there's a couple of forces at work. There's a component of the weight facing downhill. More weight also makes it tougher for the car to accelerate. And there's also an increase in static friction which applies to all four wheels (which you have to overcome to get a car moving).

Yes, sandbags help because it shifts the weight distribution, but I'm not sure a global increase in weight (without changing weight distribution) helps or hurts (esp. in an uphill situation). And one thing I forgot to mention is that all of the other cars in the example have weight distribution biased more heavily to the drive wheels than the Model S:
Roadster 35/65, NSX 42/58
Volt 61/39
Model S 48/52

 

[mknox]

You only get the message when you park the car. It drove completely normally for 300 km and gave me the message when I parked it. I guess the pack temperature was a little lower than the control system liked, but it was 100% working normally.

Good to know. Thanks.

 

[kevincwelch]

While I am encouraged by your post, I don't think your test is completely valid. The conditions appear much better during your second run. I can't account for temperature while looking at this, but there clearly is less snow and slush on your second run. (I realize you state there is less snow, but there is a LOT less snow. Makes me wonder if the Pirelli would have performed the same during this second run.)