Tesla's 85 kWh rating needs an asterisk (up to 81 kWh, with up to ~77 kWh usable)

[wk057]

What am I supposed to rebut? I don't know enough about the topic to make a rebuttal...maybe you can actually say definitively that Tesla is cheating everyone out of 4kWh, and did so purposefully.

All I know is that someone who is far from objective is claiming to understand the motivations behind testing results he has done, and considers them nefarious.

You said that I can't state the capacity reduction from rated capacity as fact. I said that Tesla's own software confirms it. So I'm asking you to defend your stance that I can't state it as fact when both my own observations AND Tesla's own software give the same answer.

As for motivations, I've specifically said many many many times in this thread and elsewhere that I have no idea what their motivations or reasoning behind publishing the incorrect spec was. All I know is that it is incorrect. Stating this doesn't imply a motivation or nefarious intentions. It just says that the spec is false. I have said that it's definitely a pattern, since there are multiple key specs advertised that are questionable. But I have in fact stated that it makes no sense to why they advertised this particular spec the way they have. Off-topic, on other specs regarding the P85D, yes, I strongly believe there was in fact nefarious intent (a push for Q4'14 sales). But on this one, I've never said nor implied that.

 

[McRat]

Sort of curious. Some batteries "recharge" a bit while sitting after a load is put on them.

Would this affect the Tesla pack?

ie - Test the cells by loading at 6C (or whatever the rating is), then let rest, rinse and repeat.

Not defending Tesla, but if the chemistry self-charges some after a drain, and Tesla tested the pack in such a manner, it could explain the variation?

 

[wk057]

Sort of curious. Some batteries "recharge" a bit while sitting after a load is put on them.

Would this affect the Tesla pack?

ie - Test the cells by loading at 6C (or whatever the rating is), then let rest, rinse and repeat.

Not defending Tesla, but if the chemistry self-charges some after a drain, and Tesla tested the pack in such a manner, it could explain the variation?

This is a misunderstanding of how the cell works. There is a surface charge that builds when the cell is idle, and can lower the internal resistance slightly for a short duration during discharge, but there is no "self charging." The power for this surface charge comes from the cell still, so the total measured capacity is still the same.

As a matter of fact, when accounting for internal resistance, the total measured capacity of the cells is pretty much the same over all reasonable discharge speeds.

 

[SteveG3]

No idea where they cut weight. Honestly, not particularly sure that's even relevant. If they never shipped a true 85 kWh pack, that's relevant, however.

I already noted some details on the cells I've tested here and here

hang on, you are saying that you are not sure Tesla cutting a few hundred pounds of weight would be relevant to the range?

they cut a few hundred pounds as of early August 2014. they also said this was a continuing process. here's what Elon Musk said in response to a question from Colin Rush,

"Colin Rush – Northland Capital Markets
Okay. That's perfect. And then can you talk about the weight reduction efforts that you've got going on right now with the vehicles, and how should we think about the cadence of pulling weight out of the vehicle and potential translation of that into extended range?

Elon Musk
Well, the puzzle [ph] on weight versus range is not super strong. There is an improvement but it's not a huge improvement. The Model S has gotten steadily lighter over time. It's really like, you know, it's quarter a pound here, half pound there, but the Model S in production today is at least a few hundred pounds less than that in the start of production. And we'll continue to see improvements over time.
So to get to a step change on -- I mean, there are so many pieces in the car, like you have the battery pack, the motor -- the transmission, or the gear box, the tires and wheels, the seats. I think if you've got like a big improvement any one of those items, maybe with the exception of the battery pack, it only changes the weight of the car by like 1%, 2% or something. These are all good things, but there's not like one big block [indiscernible] sitting in the car that [indiscernible] more primitive. It requires whittling away at a whole bunch of things.

JB Straubel
And the range impact is, you know, weight is one fraction of impact on range, so, even smaller than the direct percentage of weight reduction."

http://seekingalpha.com/article/2368515-tesla-motors-tsla-ceo-elon-musk-on-q2-2014-results-earnings-call-transcript?part=single



the "at least a few hundred pounds", I would take conservatively to be about, 300 to 400 pounds, and this was where an ongoing process was in August 2014. let's say it was 350 pounds at that point. that's about 7.6% of the weight of the Model S (estimating from memory as 4,600 pounds). something "even smaller" than a 7.6% correlating improvement in range is still large enough to account for the phenomena of an 81 kWh pack today doing exactly what an 85 kWh pack did in 2012. I know you said that based on testing some cells from a couple of battery packs you do not believe that the battery packs have changed in size since 2012... 1) how reliable is it to extrapolate from your having looked at some cells from a couple of packs that Tesla has not changed the battery sizes of their packs since 2012? looks at your sample size, look at your being one person doing testing with one set of equipment, and 2) again, if that's the case, how do you explain that range has not improved with weight of the vehicle dropping ~7.5% as of 8/2014 with Tesla continuing to work at dropping weight since then?

 

[wk057]

hang on, you are saying that you are not sure Tesla cutting a few hundred pounds of weight would be relevant to the range?

they cut a few hundred pounds as of early August 2014. they also said this was a continuing process. here's what Elon Musk said in response to a question from Colin Rush,

"Colin Rush – Northland Capital Markets
Okay. That's perfect. And then can you talk about the weight reduction efforts that you've got going on right now with the vehicles, and how should we think about the cadence of pulling weight out of the vehicle and potential translation of that into extended range?
Elon Musk
Well, the puzzle [ph] on weight versus range is not super strong. There is an improvement but it's not a huge improvement. The Model S has gotten steadily lighter over time. It's really like, you know, it's quarter a pound here, half pound there, but the Model S in production today is at least a few hundred pounds less than that in the start of production. And we'll continue to see improvements over time.
So to get to a step change on -- I mean, there are so many pieces in the car, like you have the battery pack, the motor -- the transmission, or the gear box, the tires and wheels, the seats. I think if you've got like a big improvement any one of those items, maybe with the exception of the battery pack, it only changes the weight of the car by like 1%, 2% or something. These are all good things, but there's not like one big block [indiscernible] sitting in the car that [indiscernible] more primitive. It requires whittling away at a whole bunch of things.
JB Straubel
And the range impact is, you know, weight is one fraction of impact on range, so, even smaller than the direct percentage of weight reduction."

the "several hundred pounds", I would take to be about, 300 to 400 pounds, and this was where an ongoing process was in August 2014. let's say it was 350 pounds at that point. that's about 7.6% of the weight of the Model S (estimating from memory as 4,600 pounds). something "even smaller" than a 7.6% correlating improvement in range is still large enough to account for the phenomena of an 81 kWh pack today doing exactly what an 85 kWh pack did in 2012. I know you said that based on testing some cells from a couple of battery pack you do not believe that the battery packs have changed in size since 2012... but, again, if that's the case, how do you explain that range has not improved with weight of the vehicle dropping ~7.5% as of 8/2014 with Tesla continuing to work at dropping weight since then?

Sure, cutting significant weight can increase range. Not saying that isn't the case. I'm just saying that has nothing to do with the nameplate rating of the battery, which hasn't changed.

As for "several hundred pounds", in Tesla speak that could be 1200 lbs. lol. But anyway, as Musk says in your own quote, it's not a huge range improvement. For example, if I have three adults in my car vs just myself (easily "several hundred pounds" difference), there is no noticeable range difference. It's there, but it's negligible.

 

[zswilliams]

the "several hundred pounds", I would take to be about, 300 to 400 pounds, and this was where an ongoing process was in August 2014. let's say it was 350 pounds at that point. that's about 7.6% of the weight of the Model S (estimating from memory as 4,600 pounds). something "even smaller" than a 7.6% correlating improvement in range is still large enough to account for the phenomena of an 81 kWh pack today doing exactly what an 85 kWh pack did in 2012. I know you said that based on testing some cells from a couple of battery pack you do not believe that the battery packs have changed in size since 2012... but, again, if that's the case, how do you explain that range has not improved with weight of the vehicle dropping ~7.5% as of 8/2014 with Tesla continuing to work at dropping weight since then?

1: WK has stated that he has tested cells from a very early VIN and later VINs and they show identical capacity.
2: You are alleging that battery pack capacity has dropped to some degree that correlates with reduction in weight.
3: You are asking WK to explain why range hasn't improved in spite of a reduction in weight (implying there must be a reduction in battery capacity).

I'm sorry, but WK has backed up his allegations with data. He doesn't have to provide a reason why range hasn't changed to back up his already well reasoned argument. You would have to dig in and provide a reason as to why range hasn't changed, in order for it to be considered a factor here. At the moment, all you have is supposition, which really feels like it isn't even a hypothesis at this point.

 

[Nismode]

Let me be absolutely clear here, which is going to require bold large font text:

THERE IS NO CAPACITY AVAILABLE TO THE END USER BELOW 0 MILES ON THE DASH. ZERO MEANS ZERO. PERIOD!

"But, wk! People have driven below zero! You're wrong!" I'm not. The only reason that OCCASIONALLY people have been able to drive below zero is because Tesla's algorithm for determining capacity is not perfect. Depending on many factors, the algorithm can under-estimate the amount of power available at a given time, and thus when the pack reaches 0 miles the algorithm realizes it wasn't properly calibrated when it sees a higher voltage than was expected at this point based on it's estimate of capacity. So it will let the user drive until the actual low voltage cut point, which will still leave the 4 kWh anti-brick/cell-safety buffer in the pack. There are zero guaranteed miles available below zero miles showing on the dash. There is no programmed reserve. There is no user available buffer. PLEASE, I beg everyone, PLEASE stop saying that there is. You're going to get someone stranded when they think they can push it past zero.

I mean, can't the same be said for ICE vehicles that have a "miles till empty" readout? The car underestimated its range based on driving habits/fuel usage, much like the Model S does.

I don't think people are saying there's a guarantee so much as it's not super accurate. I don't think people should, in general, drive so low to a buffer.

Just my two cents on what you said here. Going to carry on and read comments and see how this unfolds lol

 

[McRat]

This is a misunderstanding of how the cell works. There is a surface charge that builds when the cell is idle, and can lower the internal resistance slightly for a short duration during discharge, but there is no "self charging." The power for this surface charge comes from the cell still, so the total measured capacity is still the same.

As a matter of fact, when accounting for internal resistance, the total measured capacity of the cells is pretty much the same over all reasonable discharge speeds.

Gotcha. I've never experimented with that on Li batteries.

It is a tip for a dead Lead Acid that had a drain on it (left a minor load on it, not dead, but not enough to start an engine). Disconnect battery for 30 minutes and try again. Sometimes it works. Saved my arse once in the desert.

My daughter did a Science Fair project on brands of flashlight batteries. This really screwed us up. We started all the flashlights, ran until the light dimmed, shut them off together quickly, then checked the voltages. The numbers climbed as we disassembled the 16 cheapo flashlights (4 brands of batteries).

 

[wk057]

I mean, can't the same be said for ICE vehicles that have a "miles till empty" readout? The car underestimated its range based on driving habits/fuel usage, much like the Model S does.

I don't think people are saying there's a guarantee so much as it's not super accurate. I don't think people should, in general, drive so low to a buffer.

The Model S rated range display is NOT based on driving habits. It's calculated directly from the BMS's reported usable capacity value and a static Wh/mi number.

The BMS has the final say on when the battery is no longer usable for driving, and the capacity calculation can go out of whack in either direction (generally under-reports a little), especially when you never charge to 100% or even 90%, or never discharge very low, resulting in a couple of miles available past zero SOMETIMES while it re-calibrates on the low end.

But there are people saying things like there always being a dozen miles below 0, or posting that damn graphic that erroneously shows several kWh available below 0. This is a problem, since neither is even close to correct.

 

[JohnSnowNW]

You said that I can't state the capacity reduction from rated capacity as fact. I said that Tesla's own software confirms it. So I'm asking you to defend your stance that I can't state it as fact when both my own observations AND Tesla's own software give the same answer.

As for motivations, I've specifically said many many many times in this thread and elsewhere that I have no idea what their motivations or reasoning behind publishing the incorrect spec was.

I should have been clearer then, which I definitely wasn't. I meant stating it in the context of Tesla being misleading. This seemed obvious to me, but I think you're right that it doesn't read that way.

As to Tesla being "nefarious" this is where that came from. The implication that they are being purposefully misleading, and are profiting from this deception.

I'm not saying it's a huge deal, I'm just pointing it out because it's yet another thing to add to the list of where Tesla has not been completely honest with customers.

What I do want is for Tesla to start advertising honest specifications for their products. Their products sell themselves. They don't need these lies to push them, and they should realize that.

 

[SteveG3]

Sure, cutting significant weight can increase range. Not saying that isn't the case. I'm just saying that has nothing to do with the nameplate rating of the battery, which hasn't changed.

As for "several hundred pounds", in Tesla speak that could be 1200 lbs. lol. But anyway, as Musk says in your own quote, it's not a huge range improvement. For example, if I have three adults in my car vs just myself (easily "several hundred pounds" difference), there is no noticeable range difference. It's there, but it's negligible.

glad you acknowledge that reducing weight will add range. I think a 7.5% reduction in weight as of August 2014 is a reasonably conservative estimate of the public remarks from Musk and Straubel in August 2014. they said it was an ongoing process. if they kept reducing weight half as well as they had at that point, we would now have a Model S over 10% lighter than the original Model S in 2012 which the public came to know as the Model S P85 or Model S 85.

with this agreed upon this brings us back to my original point,

---

isn't it possible that,

-the early 2012 Model S were built to use XY kWh of a battery pack that really was 85 kWh, as Tesla determined that XY kWh usable got them to a range that would hit an EPA number (265 miles) they selected for the biggest battery.
- as weight came off the car from continual changes across the design of the car, lower weight meant that a usable capacity lower than XY kWh was sufficient to deliver the same range as the original battery pack that actually had 85 kWh
- over time, these changes would mean that Tesla went from an 85 kWh battery pack to various small changes up through the one you tested and measure as 81 kWh. they didn't change the Model S 85 kWh offering to say, an 83.6 kWh Model S, then an 82.9 kWh Models S, etc... but rather knew they were delivering the same range as the original 85 kWh battery.

just to say, having spent all of ten minutes thinking about it (and not even having the knowledge to consider possible errors in your testing or calculations), there may be other explanations to this. not saying I disagree with your posting this, and raising questions.

as to why Tesla would do this, isn't it understandable when your product is known to the consumer as either a Model S P85, 85, 60, 85D, 70D, etc., and you continued to offer the exact same range and performance, you would not change the name of a consumer product from those to something like,

February 2013- June 2013: The Model S 84.2 or 59.4

July 2013-December 2013: The Model S 83.3 or 58.8

January 2014- May 2014: The Model S 82.6 or 58.3

June 2014- : The Model S 81.8 or 57.8
---


I just don't think we have enough information here to say that when Tesla started selling the car, they told the public they were selling them an 85 kWh Model S when it was really an 81 kWh Model S. I don't think we have anywhere near enough information to make that conclusion, and personally, given that the weight of the car if probably 10% less than what it was back then, I really doubt that the 81 kWh 2012 Model S scenario happened.

 

[Uncle Paul]

In addition to the traction battery pack, there is also a 12v additional battery. Was this secondary battery capacity included in the OP's calculations? How much difference would it make on total battery calculations if it was included?

 

[Cottonwood]

Sure, cutting significant weight can increase range. Not saying that isn't the case. I'm just saying that has nothing to do with the nameplate rating of the battery, which hasn't changed.

As for "several hundred pounds", in Tesla speak that could be 1200 lbs. lol. But anyway, as Musk says in your own quote, it's not a huge range improvement. For example, if I have three adults in my car vs just myself (easily "several hundred pounds" difference), there is no noticeable range difference. It's there, but it's negligible.

I just did an example in EV Trip Planner, setting the parameters to 85, 19"; 1.0, 72, 72, and 200 lbs in the cabin for a trip from Mobile, AL to New Orleans, LA. Then I changed the load to 650 lbs or 450 lbs more. Both gave an identical need of 167 rated miles to cover 145.4 miles at an average speed of 68 mph, with most miles covered at 72 mph. Looking closer, the 200 lb run needed 50.0 kWh and the 650 lb run needed 50.1 kWh or 0.2% increase in energy needed for a weight difference of 450 lb, about 7.5%.


It seems to me that wk057 has done a good scientific/engineering job of analyzing the actual energy capacity of the Tesla 85 kWh battery pack and it seems to be 81 kWh. It would be nice for someone to duplicate wk057's results, but I have no reason to doubt them given the quality of his previous posts.

Does the labeling of an 81 kWh pack as 85 kWh bother me? Some, but so do the horsepower claims and the horsepower reality. Would it be nice to see more precise labeling? Yes, but that is about as important to me as Tesla greatly reducing the 1-2 kWh a day thirst of the idle Vampire.

Would I buy another Tesla knowing what I know today? Probably...

 

[zswilliams]

I just don't think we have enough information here to say that when Tesla started selling the car, they told the public they were selling them an 85 kWh Model S when it was really an 81 kWh Model S. I don't think we have anywhere near enough information to make that conclusion, and personally, given that the weight of the car if probably 10% less than what it was back then, I really doubt that the 81 kWh 2012 Model S scenario happened.

WK hasn't made any such conclusion. He stated what cells he tested and the results, which clearly show a discrepancy of available energy vs advertised energy.

You are guessing at the percentage weight reduction. You are also guessing it has some measurable impact on range. Additionally, you are casting doubt (with no evidence) that Tesla didn't have an 81Kwh battery with initial shipments (even though WK has evidence that directly contradicts you).

You can suppose a lot of things, but so far, only one of the two of you have put forth concrete evidence.

 

[Max*]

In addition to the traction battery pack, there is also a 12v additional battery. Was this secondary battery capacity included in the OP's calculations? How much difference would it make on total battery calculations if it was included?

Then the 60kwh battery would need to be 65kwh (or whatever)

 

[wk057]

I should have been clearer then, which I definitely wasn't. I meant stating it in the context of Tesla being misleading. This seemed obvious to me, but I think you're right that it doesn't read that way.

As to Tesla being "nefarious" this is where that came from. The implication that they are being purposefully misleading, and are profiting from this deception.

Sounds like you're reading too much into what I was saying and drawing your own conclusions as to my intentions. Fortunately, you don't have to do that since I clearly explained my reason for posting the info in the first post.

glad you acknowledge that reducing weight will add range. I think a 7.5% reduction in weight as of August 2014 is a reasonably conservative estimate of the public remarks from Musk and Straubel in August 2014. they said it was an ongoing process. if they kept reducing weight half as well as they had at that point, we would now have a Model S over 10% lighter than the original Model S in 2012 which the public came to know as the Model S P85 or Model S 85.

with this agreed upon this brings us back to my original point,

I just don't think we have enough information here to say that when Tesla started selling the car, they told the public they were selling them an 85 kWh Model S when it was really an 81 kWh Model S. I don't think we have anywhere near enough information to make that conclusion, and personally, given that the weight of the car if probably 10% less than what it was back then, I really doubt that the 81 kWh 2012 Model S scenario happened.

We have more than enough info to prove that dropping 400 lbs along with 4 kWh is going to result in a *decrease* in range, not an increase. This scenario you describe just is not plausible. Dropping even 400 lbs from the car is not going to add ~12+ miles of range (~4kWh), and let them ditch that battery capacity. It just doesn't work like that. Dropping the weight will help efficiency when getting up to speed, but it does almost nothing to extend range once cruising at highway speeds, and thus has a minimal effect on the actual range of the car. And again, Musk himself said basically the same thing in the quote you posted.

Having tested cells from a signature S that fit neatly with my other data, I'm more than confident that the scenario you describe is not the case. Feel free to provide data to disprove this, but I don't see it.

- - - Updated - - -

In addition to the traction battery pack, there is also a 12v additional battery. Was this secondary battery capacity included in the OP's calculations? How much difference would it make on total battery calculations if it was included?

The capacity of the 12V battery might as well be zero. I don't have the numbers in front of me, but I know it's less than 0.5 kWh at super low discharge rates.

 

[SteveG3]

Sounds like you're reading too much into what I was saying and drawing your own conclusions as to my intentions. Fortunately, you don't have to do that since I clearly explained my reason for posting the info in the first post.



We have more than enough info to prove that dropping 400 lbs along with 4 kWh is going to result in a *decrease* in range, not an increase. This scenario you describe just is not plausible. Dropping even 400 lbs from the car is not going to add ~12+ miles of range (~4kWh), and let them ditch that battery capacity. It just doesn't work like that. Dropping the weight will help efficiency when getting up to speed, but it does almost nothing to extend range once cruising at highway speeds, and thus has a minimal effect on the actual range of the car. And again, Musk himself said basically the same thing in the quote you posted.

Having tested cells from a signature S that fit neatly with my other data, I'm more than confident that the scenario you describe is not the case. Feel free to provide data to disprove this, but I don't see it.

could you cite the evidence for your assertion that dropping 400 pounds in weight would not improve range by as much as ~12 miles?

as to your motivations, all I've said about what you've done is that I think it's good you did it, good you shared it, but that I don't think there's anywhere near enough information to conclude that Tesla had an 81 kWh car on the market in 2012 that they were badging and referring to as the P85 or 85. frankly, I don't know why you've brought up the question of your motivations.

 

[apacheguy]

"But, wk! People have driven below zero! You're wrong!" I'm not. The only reason that OCCASIONALLY people have been able to drive below zero is because Tesla's algorithm for determining capacity is not perfect. Depending on many factors, the algorithm can under-estimate the amount of power available at a given time, and thus when the pack reaches 0 miles the algorithm realizes it wasn't properly calibrated when it sees a higher voltage than was expected at this point based on it's estimate of capacity. So it will let the user drive until the actual low voltage cut point, which will still leave the 4 kWh anti-brick/cell-safety buffer in the pack. There are zero guaranteed miles available below zero miles showing on the dash. There is no programmed reserve. There is no user available buffer. PLEASE, I beg everyone, PLEASE stop saying that there is. You're going to get someone stranded when they think they can push it past zero.

The troubling thing to me is that the range algo does not adjust to "add back" those miles below zero to the top end. Folks who have driven past 0 report their 90% range numbers being the same both before and after the ordeal.

The other point that doesn't make much sense is the dashed kW limiter. In some instances, the pack will cut power while the limiter is set to 20 kW and other instances it is set at 60 kW when all power is dropped. Go figure.

 

[wk057]

could you cite the evidence for your assertion that dropping 400 pounds in weight would not improve range by as much as 12 miles?

as to your motivations, all I've said about what you've done is that I think it's good you did it, good you shared it, but that I don't think there's anywhere near enough information to conclude that Tesla had an 81 kWh car on the market in 2012 that they were badging and referring to as the P85 or 85.

As I'm not the one trying to make the assertion that dropping 400 lbs *would* improve range by 12 miles, I'm not going to spend any resources trying to prove nor disprove it. But, there is a simple way for anyone with an S to test this. Get in your car, drive somewhere by yourself. Then drive the same trip with 3 more people in the car. I guarantee that you're not going to end up 12 miles shorter on range. I personally have driven from NJ->FL->NC->NJ->NC several times both by myself and with a full car of adults (easily 500 lbs of people and luggage plus myself). There is no significant change in range... maybe a mile or two at most.

But here's the main thing. Let's for a second say that somehow you're right and they've been slowly decreasing the battery's range. How exactly does that excuse them from advertising the wrong spec? Seems like they should be all over that. "We made the car more efficient, so a smaller battery gets the same range! We're awesome!" ... but they're not. So even if you're correct, which I'm fairly certain is not the case, then they're still misrepresenting the pack size today even if they weren't at launch.

- - - Updated - - -

The troubling thing to me is that the range algo does not adjust to "add back" those miles below zero to the top end. Folks who have driven past 0 report their 90% range numbers being the same both before and after the ordeal.

The other point that doesn't make much sense is the dashed kW limiter. In some instances, the pack will cut power while the limiter is set to 20 kW and other instances it is set at 60 kW when all power is dropped. Go figure.

The range algo does eventually adjust, but it's averaged over more than just one cycle. So one trip below zero isn't going to fully fix things.

As for the limiter, there is a cut voltage. If you're at a 60 kW limit, then you accelerate just a little too quickly, you're going to drag the pack to at or below that cut voltage for a moment, and the BMS is going to cut you off. But you can be limited to 20 kW, drive very very gently, and never go under the cut voltage until it actually gets there.

 

[apacheguy]

The Model S rated range display is NOT based on driving habits. It's calculated directly from the BMS's reported usable capacity value and a static Wh/mi number.


The BMS has the final say on when the battery is no longer usable for driving, and the capacity calculation can go out of whack in either direction (generally under-reports a little), especially when you never charge to 100% or even 90%, or never discharge very low, resulting in a couple of miles available past zero SOMETIMES while it re-calibrates on the low end.

FlasherZ reports seasonality in his range numbers. I don't see how this is possible with a static Wh/mi. What is this static value?

Ah, ok. So the pack must be under predicting available kWh due to colder temps.