Data on Cold Weather Range Decrease

[camalaio]

Aren't they already using that heat to warm the batteries? Is there an abundance of excess heat from the motors to do both? And how does that work at low motor usage. Ex. low speeds, stop and go, parked waiting for kids in school pickup.

It doesn't really work in the context of the Model 3's setup, which is likely why they don't do it. In cold environments, the motors don't get all that warm in either city or short hop highway driving (and certainly not quickly). But for longer travel, a heat pump would finally have some heat to move which would help for those longer trips.

On especially cold days, a heat pump wouldn't be useful for heating the cabin until a number of hours of driving.

The batter heats up prior to supercharging. That heat is then dumped through the radiator after supercharging. If it could be used to make the cabin heating more efficient by connecting the evaporator loop to the battery, that’s an efficiency increase.

The motors can be commanded to produce 3.5 kW of heat each at any time, regardless of driving conditions. That heat can be dumped into the evaporator and transferred to the cabin in extremely cold conditions where the heat pump wouldn’t be able to provide sufficient output in air-source mode.

That's just too much heat to dump in what's probably an already-warm cabin, unfortunately. A 1000lb battery at 50C (>120F) has a lot of heat in it. They try to dump it fast in order to keep the batteries in good health rather than trickle the heat into the cabin at the expense of the battery health.

 

[Yragorn]

On cold temps (-15 -30C) / snowstorms, the highest loss I've had was 50% just like everyone else. Standard loss is 30-40% on regular cold days. My cabin temp is set to 19C, 18in wheels. Must not forget that winter tires are less efficient than summer tires on top of having cold weather atmosphere which is harder for the car to "pierce through" when driving.
I killed the temperature once since I had to save energy on my way home, and it saved me 50Wh/km

 

[arch4life]

M3P-, 18's with aeros off, michigan, 80% highway driving @ >70mph, usually 75+

 

[SSedan]

I live near Green Bay so real winters though this one has been mild. We are expected fall to -8 to -10 f tomorrow night though.
Have a 2014 P85
My 6.5 mile drive to work will triple fair weather energy use if o don't warm up on shore power when single digits f or below.

Still I have no problem making the 180 (242m 100% )mile drive to the Eau Claire supercharger at low single digits.

I think too few here differentiate between range and efficiency. Efficiency takes a pounding in daily driving, but range on long trips is not impacted nearly as much.

 

[derotam]

The backup heat source would be the motors themselves. Think Model 3 battery heating and dump that heat into the evaporator side of the heat pump system.

I don't think there would be enough heat generated in normal driving at lower temperatures to appropriately warm the cabin. I drive an hour to and from work and at outside temps of <40F, the Stator gets to maybe ~25C(77F) Go down to 10-20F or less and even that won't be enough for supplemental heat.

The motors can be commanded to produce 3.5 kW of heat each at any time, regardless of driving conditions.

This is partially incorrect. The front motor can be commanded the ~3.5kW for normal driving up to ~90MPH at least since that is the point at which in normal cruising on dry roads the front motor actually starts providing constant propulsion. Reference is one of Bjorns videos where he was trying to drive at >200km/h.

The REAR motor at least so far, cannot make use of the full 3.5kW for heating while in motion. This can be seen by watching the stator temperature in ScanMyTesla while driving at speed. If you are driving at 60MPH and turn on battery preconditioning via routing to a supercharger, you will not see the stator increase in temperature very fast if at all...as soon as you slow down to hold mode you will see the stator temperature drastically rise in a short period of time. This graph of data that I took Imgur on my LR RWD vehicle shows this. Preconditioning was turned on during the first flat speed portion of the drive. You can see the stator temperature go up, down, and level off throughout the graph.

 

[arch4life]

This is a very important point. Due to this it might be beneficial for COLD temperature long distance travel to have AWD, if the on route warming capability is more than halved with the LR RWD. I have not had the inconsistency of supercharger speeds others report in the winter, which may be because of the additional heat provided by the front motor during driving.

perhaps this is another reason tesla killed the long range rwd car?

 

[Nocturnal]

From my observations you are looking at about 20% drop in range from very cold temps (below freezing). Then remember that driving at highway speeds also lowers range compared to rated levels, as can heat. I think 40% is a conservative estimate for high speeds in the cold with heat blasting.

 

[Big Earl]

I don't think there would be enough heat generated in normal driving at lower temperatures to appropriately warm the cabin. I drive an hour to and from work and at outside temps of <40F, the Stator gets to maybe ~25C(77F) Go down to 10-20F or less and even that won't be enough for supplemental heat.



This is partially incorrect. The front motor can be commanded the ~3.5kW for normal driving up to ~90MPH at least since that is the point at which in normal cruising on dry roads the front motor actually starts providing constant propulsion. Reference is one of Bjorns videos where he was trying to drive at >200km/h.

The REAR motor at least so far, cannot make use of the full 3.5kW for heating while in motion. This can be seen by watching the stator temperature in ScanMyTesla while driving at speed. If you are driving at 60MPH and turn on battery preconditioning via routing to a supercharger, you will not see the stator increase in temperature very fast if at all...as soon as you slow down to hold mode you will see the stator temperature drastically rise in a short period of time. This graph of data that I took Imgur on my LR RWD vehicle shows this. Preconditioning was turned on during the first flat speed portion of the drive. You can see the stator temperature go up, down, and level off throughout the graph.

I wasn't proposing that the cabin be heated exclusively with waste heat from the battery pack - just that it's an option for boosting heat pump efficiency in some situations (like post-Supercharging). It could also harvest heat from the front motor in an active heating mode like Supercharger preconditioning, providing "emergency heat" to the cabin without the need for a PTC heater.

I'll have to go through and watch some of Bjorn's videos again. I seem to recall the front and rear stators being hot while driving, but I could be remembering incorrectly.

At the end of the day, switching to a heat pump system, while significantly more complex, could boost winter range quite a bit. If such a system is in the works, it will be interesting to see how reliable it is long term.

 

[Uncle Paul]

Experienced owners learn to mitigate reductions in efficiency by charging them a bit prior to leaving your garage. This can use shore power to warm the battery as well as the interior. Doing so would greatly mitigate some of those worst case senarios you are digging up.

Starting out with a warm battery can really reduce battery drain, especially for shorter trips.

If range is your biggest issue in cold weather, you can use your seat warmers and heated steering wheels (if equipped) to keep you comfy instead of turning the heat way up.

Lots of little things owners can do if the reduction in cold weather range becomes a real issue.

 

[SSedan]

I said this in another thread I have air source heat pumps at home and actual experience daily driving and some long trips in a Tesla S in genuinely cold weather, near Green Bay. For those who think 40F is cold and Bjorn is the epitome of cold weather user, Oslo is slightly warmer winter temps than Chicago. LOTS of us in the continental US live in colder places

The way heat pumps need to be periodically heated to defrost poses a problem for cars. My house has sufficient volume to withstand a 10 minute AC defrost cycle where it blows cold air in the house, a car can not.

The statements about 20-40% range reduction are efficiency reductions on shorter trips.

RANGE should be used to describe longer trips and in my experience I did not see a 20% reduction at single digits. Yes I see a tripling of energy use on a 6.5mile drive to work when cold, but it doesn't translate to long trips.

If you are seeing 20% reduction on long drives above zero, use the seat heat more and a jacket, you are getting carried away with the HVAC.

 

[derotam]

I wasn't proposing that the cabin be heated exclusively with waste heat from the battery pack - just that it's an option for boosting heat pump efficiency in some situations (like post-Supercharging). It could also harvest heat from the front motor in an active heating mode like Supercharger preconditioning, providing "emergency heat" to the cabin without the need for a PTC heater.

I'll have to go through and watch some of Bjorn's videos again. I seem to recall the front and rear stators being hot while driving, but I could be remembering incorrectly.

At the end of the day, switching to a heat pump system, while significantly more complex, could boost winter range quite a bit. If such a system is in the works, it will be interesting to see how reliable it is long term.

Yes I am also in favor of some kind of heat pump in the Tesla. I know a lot of people try and say that "tesla knows best" but the winter range issue is a big psychological issue for a lot of users and I would be willing to bet that other manufacturers will do something to "even out" the experience.

 

[golfpilot]

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• golfpilot
• Feb 12, 2020

 

[camalaio]

I said this in another thread I have air source heat pumps at home and actual experience daily driving and some long trips in a Tesla S in genuinely cold weather, near Green Bay. For those who think 40F is cold and Bjorn is the epitome of cold weather user, Oslo is slightly warmer winter temps than Chicago. LOTS of us in the continental US live in colder places

The way heat pumps need to be periodically heated to defrost poses a problem for cars. My house has sufficient volume to withstand a 10 minute AC defrost cycle where it blows cold air in the house, a car can not.

The statements about 20-40% range reduction are efficiency reductions on shorter trips.

RANGE should be used to describe longer trips and in my experience I did not see a 20% reduction at single digits. Yes I see a tripling of energy use on a 6.5mile drive to work when cold, but it doesn't translate to long trips.

If you are seeing 20% reduction on long drives above zero, use the seat heat more and a jacket, you are getting carried away with the HVAC.

For me and certainly some others on this forum, it does translate to long trips. Or at least I'm defining that as within the confines of one charge on the highway. When going to about where my wife works and back (2h of driving total, about 130km) takes almost 60% of the LR battery, this can't be blamed on just short hop costs. That's with preheating at home in a garage before leaving as well.

At such temperatures I don't think it's wrong to use HVAC at a reasonable temperature (21C in my case). I'd rather be able to feel my feet and hands so I can control the vehicle, which seat heat won't provide.

Am curious how you're not seeing even 20% at "single digits" though (which I presume to be fahrenheit? So under -12C). Almost as if you drive a different vehicle from most people on this forum, or perhaps you're measuring it a different way?

Yes I am also in favor of some kind of heat pump in the Tesla. I know a lot of people try and say that "tesla knows best" but the winter range issue is a big psychological issue for a lot of users and I would be willing to bet that other manufacturers will do something to "even out" the experience.

It's more than a psychological issue, it's a financial and waste issue as well to be fair!

 

[SSedan]

I am driving an S so my drive consumption is higher which may reduce the percentage gain due to heat use.
Not sure if I said that well.
If heating the cabin takes 50wh/m that is a 20% rise on a 3 vs only a 16% rise for my car.
I tend to keep winter car temp at 65f which is ballpark 18-9C and use the seat heater. Does the 3 tend to run the fan harder than the S?

Maybe my opinion is a little skewed too since as odd as this may sound, my long stretch to the next westbound supercharger is mostly 55mph roads so I am not facing a speed penalty.

Cold air is more dense so it would make sense that the extra use from speed would be greater in cold weather. Like I said I don't see it due to the modest speeds my long stretch is.

 

[GtiMart]

I'm in Quebec City and only do 5-10km drives for the most part. I'm around 50% loss even when it's not that cold, and it goes better around 40% loss as temperature rises to 0C and better. Preheating, heating, winter tires and short trips really kill it.
As others said, on longer trips it's probably better. I haven't done any yet.

Edit: oh, and less regen when the battery is cold unless you preheat.

 

[camalaio]

I am driving an S so my drive consumption is higher which may reduce the percentage gain due to heat use.
Not sure if I said that well.
If heating the cabin takes 50wh/m that is a 20% rise on a 3 vs only a 16% rise for my car.
I tend to keep winter car temp at 65f which is ballpark 18-9C and use the seat heater. Does the 3 tend to run the fan harder than the S?

Maybe my opinion is a little skewed too since as odd as this may sound, my long stretch to the next westbound supercharger is mostly 55mph roads so I am not facing a speed penalty.

Cold air is more dense so it would make sense that the extra use from speed would be greater in cold weather. Like I said I don't see it due to the modest speeds my long stretch is.

Oh, yeah I missed the Model S part. I just assumed Model 3 since we're within that as a subforum, sorry.

I'm usually going somewhere around 100km/h (62mph), that 7mph I've noticed is actually quite large but I'm already factoring that into my loss numbers (what I've said so far is relative to warmer driving conditions on the same roads). The worst losses in range I've experienced are actually at lower speeds, which makes sense given the heating losses (takes longer, more heating required).

I don't know if it's a difference between the 3 and the S, but I find the heat rather lacking unless we set it to 22C. It just doesn't feel like warm air is consistently coming out until that point. It's not like my previous ICE car where it would use a low fan speed but the air was nice and warm (great on the hands and feet!). The Model 3 at 21C sort of gently leaks out lukewarm air (so, a low fan speed). This makes sense and seems to keep it warm enough, but doesn't align with my experience in nearly any other climate control system. So my hands are usually a bit colder than I'd like at the 21C I have it set to.

 

[SSedan]

I use the "new posts" option so I read more than just S topics.

If on a long trip and supercharging I am pretty aggressive with the heating towards the end of the session, build a little heat reserve.

As others have said experience can help you manage range impact of cold.

Our first family road trip I. The S was at the first cold snap of the year and I was caught off guard, diverted 30 minutes to an extra.charging stop due to being spooked by high initial consumption.

 

[Big Earl]

The 3 seems to use more energy in automatic mode to heat the cabin than S & X, which I suspect is due to very aggressive floor heating (result of poor floor heat complaints in S & X?) that gets diluted by cooler air from the vents. Turning off the floor heat and only using the dash vents significantly reduces energy consumption. I'm definitely seeing a >30% range hit in cold winter weather on extended trips in the 3 with the climate control in automatic mode at 68F.

Not complaining ... it is what it is and the range is still sufficient for my needs. I also have alternatives like using manual climate control if I need to extend range when traveling on the edges of the Supercharger network.

 

[Subhuman]

20%-30% range loss in the winter is pretty standard for me but it can be more depending on how cold it gets. I have a 160 mile daily commute to work and have had some close calls. I had to turn the heat off to make sure I had enough power to get home a few times.

I do plug in to a standard 110v outlet at work but once temperature are in the 20’s, the car will not add charge. However it does prevent range loss from the car sitting in the cold all day. You can loss around 5% with you car just sitting in the cold all day.

I charge to 90% daily and commonly end up arriving at home with less than 10% charge even while plugged in to a 110v outlet at work all day.

Range lose in cold weather is the primary reason we need 400 and 500 mile battery packs.

 

[hcdavis3]

Experienced owners learn to mitigate reductions in efficiency by charging them a bit prior to leaving your garage. This can use shore power to warm the battery as well as the interior. Doing so would greatly mitigate some of those worst case senarios you are digging up.

Starting out with a warm battery can really reduce battery drain, especially for shorter trips.

If range is your biggest issue in cold weather, you can use your seat warmers and heated steering wheels (if equipped) to keep you comfy instead of turning the heat way up.

Lots of little things owners can do if the reduction in cold weather range becomes a real issue.

As I understand this there is no such thing as shore power. By definition any juice the car uses comes from the battery. The charger simply tops off the battery as it’s used to heat or cool the car.