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Gshenderson

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Lots of thoughts but they are pretty much the same as yours. I think we are in a typical high tech ramp up. Manufacturers will be leapfrogging one another until such time as all the cars have 800 miles range based on million mile batteries. Obviously Tesla has more resources to throw at battery research than Rivian and a little more time so I think it is reasonable to assume that the CT will be a bit ahead of the game in this department relative to Rivian. When Rivian announced a vehicle with 400 miles range I leapt. But that was a couple of years ago. Four hundred miles is sort of the minimum acceptable at this point. Is this enough for me to cancel my Rivian reservation and wait longer for a CT? No, no, no!
Ugly is still ugly, regardless of battery tech! I’ve got a CT reservation - mostly because I had too much to drink one night. I never intended to own one, but for $50 it was worth jumping into the craze. My rationale was If they really took off, I get one really early as a current Tesla owner and then flip it for a small profit. I likely won’t do that now, but will get my $50 back and go to Starbucks.
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kanundrum

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Dramatic loss of performance in cold weather was a large part of early BEV FUD. And there was something to it. But with BMS that carefully regulate battery temperature and clever schemes for capture of waste heat it is, I believe, a thing of the past. At least around here. I can't speak for conditions up north as I flee those regions to avoid them. Note that there have been some recent reports of problems with Octovalves in Quebec.

Around DC you probably won't notice much if anything. I actually get slightly better consumption here in the winter than I do up north in the warmer summer weather.

There is one huge cold weather factor that definitely does have a profound effect on consumption and that is snow, slush or water on the roadbed. Of course one can have water on the road in summer too. Water will take my consumption from around 280 Wh/Mi (X LRP) up to 350. That business we had around here a week or so ago (some snow accumulation on the Beltway) took me up to 535, that is, it almost cut my range in half. So don't worry so much about the cold itself. Do think about precipitation when planning.

Interesting but I would disagree. Dramatic loss in cold climate is in fact a real thing. DO you mean to tell me your Tesla Model X reports no loss of distance in cold climates?

My hyundai ioniq EV always has a reduction of 30% of distance with the HVAC on in sub 32F degree temperature (Just tested this last week when we had a High of 33 and a low of 25). The whole goal of BMS and Thermal management testing and configuration optimization is to reduce that 30% figure (Real world loss) in colder climates. I would find it hard to believe that nothing can't be optimized to reduce the thermal loss of the cells even if its a few small % points since RIvians tech could be a bit better based on their Thermal Management implementation.
 

C.R. Rivian

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Interesting but I would disagree. Dramatic loss in cold climate is in fact a real thing. DO you mean to tell me your Tesla Model X reports no loss of distance in cold climates?

My hyundai ioniq EV always has a reduction of 30% of distance with the HVAC on in sub 32F degree temperature (Just tested this last week when we had a High of 33 and a low of 25). The whole goal of BMS and Thermal management testing and configuration optimization is to reduce that 30% figure (Real world loss) in colder climates. I would find it hard to believe that nothing can't be optimized to reduce the thermal loss of the cells even if its a few small % points since RIvians tech could be a bit better based on their Thermal Management implementation.
My Kia Niro EV has a heat pump. I don't see a 30% reduction in miles. Admittedly, temps here have been mostly in the 40's, but still. Since Kia and Hyundai are essentially the same company (Hyundai bought Kia a few years ago), I would expect to see somewhat similar tech in their cars. Is your heat from a heat pump?
 

kanundrum

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My Kia Niro EV has a heat pump. I don't see a 30% reduction in miles. Admittedly, temps here have been mostly in the 40's, but still. Since Kia and Hyundai are essentially the same company (Hyundai bought Kia a few years ago), I would expect to see somewhat similar tech in their cars. Is your heat from a heat pump?
According to Specs my 2019 Ioniq EV does have a heat pump but I am still seeing a 25 to 30% reduction in range in sub 32F temps with HVAC, with out it on I see 18 to 20% difference in range. Talking with some Model Y friends they also see more or less a 25 to 30% range reduction in harsh climates.

" Hyundai Ioniq Electric included a heat pump on the higher “Limited” trim level for the 2019 model year, but it was removed for the US market on the 2020 model year version. "
 

ajdelange

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Interesting but I would disagree. Dramatic loss in cold climate is in fact a real thing.
Not for me. And I doubt it's "dramatic". Stats reports historical ensemble data efficiency data. This does show a seasonal variation but it is about 10% between summer and winter.

DO you mean to tell me your Tesla Model X reports no loss of distance in cold climates?
No. Exactly the opposite. So obviously temperature is not the whole story. But temperature does not seem to have the dramatic effect that many seem to assume. At least not here In the middle of Alberta in January, maybe. And as I tried to emphasize in my last post if part of January in Alberta involves driving in even little snow, that will have profound effect.

My hyundai ioniq EV always has a reduction of 30% of distance with the HVAC on in sub 32F degree temperature (Just tested this last week when we had a High of 33 and a low of 25).
That's your Hyundai. I am quite confident, based on the apparent care Rivian seems to have taken with their engineering, that there will not be a performance reduction of that magnitude with your Rivian.

I always look at numbers. A kW is 3412 BTU/h (about a quarter of a ton). Given that your whole house is probably heated with heat pumps totaling a few tons wouldn't you think 1/4 ton would be enough for the cabin of a car? Say you are cruising at 60 mpH. In an hour you cover 60 miles and use something like 450*60 = 27 kWh for traction and 1 kWh for heat. That's less than 4%. How do you get to 30% loss from that? Or looked at from another POV the system will be pulling 27 kW from the battery. 30% loss from heating would mean that 8.1 kW (2.3 tons) of heat were being produced. Where would this heat be going.

The whole goal of BMS and Thermal management testing and configuration optimization is to reduce that 30% figure (Real world loss) in colder climates. I would find it hard to believe that nothing can't be optimized to reduce the thermal loss of the cells even if its a few small % points since RIvians tech could be a bit better based on their Thermal Management implementation.
I don't think there is much argument that the Rivian thermal management system is not capable of some improvement. The flaw in your thinking is that they are starting from 30%. We'll see when the vehicles hit the road but I am fairly certain that ensemble range loss is more likely to be in the 10% region (i.e. not that dissimilar to Tesla) rather than near 30%
 
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kanundrum

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^^ I look at the data, when my car is 100% Charged in optimal temps, range is at 142 miles as I set off, when its below 32F Range is at 120 miles with out any HVAC system. As soon as I turn it on, the range goes down to 109 miles total which I have confirmed driving somewhat long distances around town in the winter. Even recent Mach E tests from Engineering Explained who has the LR 270 Mile version show 189 miles in a very cold Climate (He lives in Utah) at 80%. From what Mach E details are their range is extremely accurate. Using that Math the 270 Mile range is now 220 miles. Which puts the loss at somewhere around 19% (With no HVAC currently on remotely in the car).

At the end of the day factoring in total loss and real world usability (Distance you can travel with your vehicle) is what matters. If a Reduction in range is only 10% its ideal but I have never seen that in real life on any BEV (Ever) in Sub 32F temps with our with out a heat pump. Real world loss in total mileage with HVAC on is still way more than 10% on any platform with real world use.

Rivian R1T R1S Video: R1T Towing 11k lbs up high grades at 118º F -- Hot Weather Towing | Progress Report by Rivian 1609612516895
 
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slawwach

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That's your Hyundai. I am quite confident, based on the apparent care Rivian seems to have taken with their engineering, that there will not be a performance reduction of that magnitude with your Rivian.
Range lost in winter is definitely not a Hyundai thing. Every EV is loosing range in winter and you can be sure that Rivian will loose it as well. Many stats can be found, but in general I find them to be in line with these findings - on average ~20% in zero Celsius.
https://www.autoweek.com/news/green-cars/a31898441/study-ev-winter-range-loss-averages-19/

Or a bit more data based on the 4200 EVs:
https://www.geotab.com/blog/ev-range/

In an hour you cover 60 miles and use something like 450*60 = 27 kWh for traction and 1 kWh for heat. That's less than 4%. How do you get to 30% loss from that? Or looked at from another POV the system will be pulling 27 kW from the battery. 30% loss from heating would mean that 8.1 kW (2.3 tons) of heat were being produced. Where would this heat be going.
The heating of the cabin is not the only energy lost. The system will also heat the battery to keep it warm and low temperature increases the internal resistance and lowers the capacity of the battery. More here:
https://batteryuniversity.com/learn/article/discharging_at_high_and_low_temperatures

Cars will try to prevent that by warming the battery, but that of course increases the heating costs.
 

ajdelange

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Range lost in winter is definitely not a Hyundai thing.
Didn't mean to imply that it is a Hyundai thing. Just that it probably won't be a Rivian thing. It definitely isn't a Tesla thing - at least not to the extent that you all seem to think,'




Every EV is loosing range in winter ..
Mine isn't. And my last one didn't either. At least not to the extent that one would take note.




and you can be sure that Rivian will loose it as well.
I can't. As I said in my first post based on my experience with Tesla and my feeling that Rivian's thermal management will be on a par with Tesla's I am assuming similar performance to Tesla's.

Many stats can be found,
I use the data collected in real time from the Tesla fleet (or the part of it that subscribes to Stats to be precise).



The heating of the cabin is not the only energy lost. The system will also heat the battery to keep it warm and low temperature increases the internal resistance and lowers the capacity of the battery.
The 5+ kW needed to explain the levels of loss you claim? Balderdash!

When a battery is cold ion mobility is low, internal resistance is high and I^2R losses correspondingly high. What happens to the energy dissipated in those losses? It goes to heat the cells! Guess what. The battery isn't cold anymore. Besides this the TMS is collecting waste heat from the inverters and motors and pumping it into the battery. An X running at 60 mpH is taking 16.8 kW from the battery to run the motors. Losses are astoundingly low (which is why it's only taking 16.8 kW) but they are still around 5% meaning 800 W of heat to be recovered and sent to the battery. That may be required in -40 ° weather but it isn't required at and near freezing. The 3 and Y have their heat pumps configured to take heat from the ambient air with COP of 3-ish so there is another source to keep the battery warm.


If a driver is experiencing 20 - 30% range loss driving a Tesla in the DC metro area in the winter months he either doesn't know how to drive his car or doesn't care. If I'm going out to run a quick errand I really don't care whether my efficiency is 80% or 100% but I do keep track of these things as a curiosity. I consistently get efficiencies in the high 90's - winter and summer (EXCEPTION: If there is stuff on the road). If I can do it, you can do it. There are a few tricks, of course, but they are widely enough known that anyone should be able to find them pretty quickly,

It is my belief that beyond residual FUD the notion of high range loss in the winter stems from blaming low temperature when it is actually things correlated with cold weather, in particular precipitation and winds, that are mainly responsible.
 

DucRider

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There are other factors to consider.
Parking outside vs in a garage will often result in lower battery temps and greater cold weather impact.
Tesla is one of only a very few manufacturers currently recapturing waste heat from the inverters/motors.
Many US spec BEVs do not have battery heaters.
Lots of short trips and cold soaking the battery (and cabin) will have a significant impact on range.
 

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ajdelange

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I rest my case. As the video clearly shows he is driving under the conditions that are guaranteed to eat his lunch: snow on the substrate. I am surprised he lost as little as 30%.

But he failed to impart any of the information that is really important: consumption. I was able to grab some numbers. On the longer drive (part of which was probably on plowed surface though even a small bit of stuff eats range) he got 191 Wh/km which is around 307 Wh/mi. I believe he said this was a P so 307 is probably fairly close to the rated consumption (I'd guess 310 Wh/mi). It's certainly not 30% greater than rated consumption.
 

Dark-Fx

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Range in my Bolt in the coldest part of Michigan winter time is less than half the range I can get in the warm spring and fall time. I've averaged under 2 mi/kWh on several days in the past where there wasn't precipitation or remnants of on the road. I've also observed driving a good distance through deep snow (8-12") at 35 mph pushing the rate of consumption over 1 kWh/mi.

My hope of using the Rivian to tow a snowmobile trailer is going to be dependent on being able to avoid needing to drive where there is actually a lot of snow on the road.
 

ajdelange

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Range in my Bolt in the coldest part of Michigan winter time is less than half the range I can get in the warm spring and fall time. I've averaged under 2 mi/kWh on several days in the past where there wasn't precipitation or remnants of on the road.
I understand that is is possible to do this. If your cabin heater is a 1 kW heater and you set cabin temperature so that it is running at 100% duty cycle while crawling along at 5 mpH because of terrible visibiity that's 200 Wh used by the heater for each mile covered,


I've also observed driving a good distance through deep snow (8-12") at 35 mph pushing the rate of consumption over 1 kWh/mi.
I've never driven in snow that deep but I have seen consumption as high as 500 Wh/mi (X LR) so I can easily believe this too. Note that your experience confirms that stuff on the road will take a lot more out of your range than just the cold. This is the main point of which I want people to be aware. There are things you can do to beat cold as long as the road surface is clear. There isn't much you can do about snow accumulation.

Presumably the Rivian will have state of the art BMS and TMS systems. They will, we hope, handle the cold part well. And, as has been noted, one can operate comfortably at lower than typical cabin temperature by using the heated seats and/or a car coat.

My hope of using the Rivian to tow a snowmobile trailer is going to be dependent on being able to avoid needing to drive where there is actually a lot of snow on the road.
That would be a double whammy for sure. At least we can assume that if there is stuff on the road you will be driving slowly thus minimizing the aerodynamic drag on the trailer.

I expect that people who drive their Rivians in sand are also going to be in for a surprise
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