Winter Testing

erlanning

Member
First Name
Eric
Joined
Oct 2, 2019
Messages
5
Reaction score
0
Location
South Algonquin, Ontario, Canada
First Name
Eric
Vehicles
Model X
I have seen only a few promotional shots of the vehicle operating in snow. Are these being actively tested in real winter's like Alaska, Canada or Norway. I would love to see if there are improvements to charge retention and energy economy in real Winter conditions... For example, my Tesla Model X does not do well in -20 C easily 50% loss of range when it is that cold, has Rivian been able to compensate for this?
 

EyeOnRivian

Well-Known Member
Joined
Feb 14, 2019
Messages
338
Reaction score
255
Location
Chicagoland
Vehicles
Mitsubishi Endeavor, pre-ordered R1S but may change to R1T
I have seen only a few promotional shots of the vehicle operating in snow. Are these being actively tested in real winter's like Alaska, Canada or Norway. I would love to see if there are improvements to charge retention and energy economy in real Winter conditions... For example, my Tesla Model X does not do well in -20 C easily 50% loss of range when it is that cold, has Rivian been able to compensate for this?
One of the places Rivian is currently testing is Tierra del Fuego in South America. Since that's in the southern hemisphere it's winter there. It's my understanding this is a popular place to test vehicles. You can read more about this in the following thread - Preproduction Rivian R1T spotted testing at Tierra del Fuego!
 
OP
E

erlanning

Member
First Name
Eric
Joined
Oct 2, 2019
Messages
5
Reaction score
0
Location
South Algonquin, Ontario, Canada
First Name
Eric
Vehicles
Model X
  • Thread starter
  • Thread Starter
  • #3
Thanks @EyeOnRivian Hope to see some data too on Winter Battery Performance.... Or maybe even take the vehicle for 3 months in my neck of the woods... PickUps (and occasional Subaru's) are in everyones driveway up here... Most folk are pretty skeptical about an Electric Vehicle let alone a truck!
 

EyeOnRivian

Well-Known Member
Joined
Feb 14, 2019
Messages
338
Reaction score
255
Location
Chicagoland
Vehicles
Mitsubishi Endeavor, pre-ordered R1S but may change to R1T
Sure, no problem. :like:

PickUps (and occasional Subaru's) are in everyones driveway up here...
I hear ya. For many years now I spend a week in Northwest Ontario fishing. Basically from International Falls and into CA it's rare to see a sedan. Like you say mostly pickups, but also SUVs and anything else that has the clearance and 4wd of course. On my next visit I plan on dropping some very strong hints to the camp owner to install a charging station ... after all it is a 5 star rating camp so I'd assume he would want to keep that way ... <wink><wink>

The EV adoption is spreading and making it's way to CA. On one of our meal stops in upper Minnesota, this hybrid was in the parking lot and it license plate gave us a good laugh:

gRO6_P5CFXaErkwT98j3mdGKemq-7xtZnV5TnZ8OdwD6yXueDu_Nz5GSE4hLb2HMeQz0oC2XdHFeOox6vN=w1162-h871-no.jpg
 

mtnras

New Member
First Name
Mark
Joined
Oct 2, 2019
Messages
3
Reaction score
2
Location
Boise, ID USA
First Name
Mark
Vehicles
Tundra, Ascent
Similar concerns here. Based in Boise, Idaho and make regular trips to the Tetons... ~350 miles. Frequently cold/blustery, I'm wondering how well the largest battery pack performs in the cold... could be a deal breaker for me.
 

ajdelange

Well-Known Member
First Name
A. J.
Joined
Aug 1, 2019
Messages
326
Reaction score
117
Location
Virginia/Quebec
First Name
A. J.
Vehicles
Tesla X 100D 2018
For example, my Tesla Model X does not do well in -20 C easily 50% loss of range when it is that cold, has Rivian been able to compensate for this?
When I see reports like this I am always a little puzzled. When I look at the statistics from Stats I see that for the X fleet (with "fleet" here meaning X drivers that subscribe to Stats) average efficiency in the winter months runs about 86% and in summer about 93%. Clearly there is a reduction in range in winter but not nearly one as dramatic as 50%. Now we have to keep in mind that there is a concentration of Teslas in California where -20 °C does not happen very often.

At the same time I look at my own statistics. Averaged over the summer I consume 294 Wh/mi whereas in winter I average 301 Wh/mi. Again, we don't get -20 °C where I spend the winter. From this I conclude that there are probably some things drivers in a cold climate can do to mitigate loss of range and at the same time there are probably things the manufacturers can do to improve cold weather performance. But there are some things, such as higher air density, higher winds and more precipitation on road surfaces that are associated with winter and reduce range that the manufacturers can do nothing about. Note that the range of ICE vehicles is reduced too but we don't tend to notice.

The long pole in the tent is always supposed to be the cabin heater. An ICE vehicle gets as much cabin heat as it wants from waste heat. In a BEV cabin heat comes from the traction supply. Tesla advises its drivers to use the seat heaters rather than the cabin heat and with the sun streaming in on a nice day even if the OAT is low one can be quite comfortable that way. At least it works that way around freezing.

Now lets look at 50% range degradation in an X. That means consumption of 600 Wh/mi with 300 (0.3 kWh/mi) lost to the cold. If you are driving 60 mph that means 18 kWh used in an hour so that the power being lost is being lost at an 18 kW rate. That's 61 kBTU/k or 5 tons of heat! Let's look at normal driving at 100% efficiency i.e. 300 Wh/mi and assume that 10% of it is lost to inverter and motor inefficiency. That's 6.1 kBTU/h or half a ton of heat which ought to be plenty to heat something the size of a truck or SUV cabin so the improvements we need of Rivian (and Tesla) is to capture that waste heat effectively and route it to the cabin. And, of course, the obvious: insulate the cabin well and minimize air leaks. Tesla has put a deal of thought into doing this as evidenced by a patent filing for a rather elaborate looking lash-up of compressors, evaporators, heat exchangers, pumps, valves and sensors which can take heat from any place where it is in excess and transfer it to anywhere it is needed. Rivian is, of course, well aware of this common criticism of BEV's and thus presumably heavily engaged in similar design. But you can't beat the physics. A 75 mpH wind at -20 °C carries a lot of cold! The battery has to be kept in a particular temperature band for best performance and the passengers have to be kept warm. If those requirements can't be fulfilled with waste heat then valuable traction energy must be used.

Rivian (and Tesla) can help the driver avoid range reduction with some simple to implement features namely those that keep him from having to depart in a cold soaked vehicle. Tesla has a feature whereby you tell the car when you want to depart and it times charging (which warms the battery) such that it completes near planned departure time and pre-warms the cabin using shore power. What Tesla does not have (AFAIK) is the ability to warm the battery to the point where full regen is available if connected to shore power. As the X has a separate battery heater this would be, IMO, an easy thing to do and would help with range.

In summary: some effects of cold can be compensated for, some can't. I, of course, have no idea what Rivian has done in this regard but I do know they are well aware of these problems and am guessing that they have focused on them intensely as range loss in winter is near the top of the FUD prophets' lists. I solve the - 20 °C problem by fleeing Quebec in the winter.
 
Last edited:

EyeOnRivian

Well-Known Member
Joined
Feb 14, 2019
Messages
338
Reaction score
255
Location
Chicagoland
Vehicles
Mitsubishi Endeavor, pre-ordered R1S but may change to R1T
Averaged over the summer I consume 301 Wh/mi whereas in winter I average 301 Wh/mi.
Nice post. So does snow-birding in Virginia actually cause your average Wh/mi to be the same (301) as a Quebec summer or is that a typo?
 

ajdelange

Well-Known Member
First Name
A. J.
Joined
Aug 1, 2019
Messages
326
Reaction score
117
Location
Virginia/Quebec
First Name
A. J.
Vehicles
Tesla X 100D 2018
Actually it's the other way round. We are summer "cottagers" up there (though Mrs is a native of Montreal). But yes, 301 for summer was a typo - it was actually 294 for last summer which is almost the same but does represent a 2% increase for winter which is small enough that it could easily be attributed to terrain, mix of rural vs. metro driving etc.
 
Top