Battery cell/pack specs

[Rivianmd]

They were testing to as low as minus 40° F

The vast majority of owners will not be operating their vehicles in that use case. I am glad they are testing the tails, but they should have implemented a heat pump given it is existing, proven, and three times more efficient

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[SANZC02]

They have published some data that guides us to the efficiency. While this information is still the current information posted, we don't know if it has evolved as the vehicles have developed.

They publish charging speeds for two different chargers. They do not specify which vehicle these are for, nor do they give specifics on the wheel configuration, which can have an impact on range.

The mobile charger provides 7.68kW of power and adds 16 miles per hour of range.
You have to deduct a percentage of that power that is lost during the charging process in order to come to the power available to add range. In this case I use a charging loss of 8% and 10%.

At a 10% charging inefficiency loss, you have 6,912 watts available to add range. Their spec indicates this would add 16 miles of range (with rounding this could be 15.51 to 16.49):
432Wh/mile - with rounding this could be between (419 to 446Wh/mile)

At an 8% charging inefficiency loss, you have 7,066 watts available to add range. Their spec indicates this would add 16 miles of range (with rounding this could be 15.51 to 16.49):
442Wh/mile - with rounding this could be between (428 to 456Wh/mile)

The hard wired charger provides 11.5kW of power and adds 25 miles per hour of range.

At a 10% charging inefficiency loss, you have 10,350 watts available to add range. Their spec indicates this would add 25 miles of range (with rounding this could be 24.51 to 25.49):
414Wh/mile - with rounding this could be between (406 to 422Wh/mile)

At an 8% charging inefficiency loss, you have 10,580 watts available to add range. Their spec indicates this would add 25 miles of range (with rounding this could be 24.51 to 25.49):
423Wh/mile - with rounding this could be between (415 to 432Wh/mile)

This at those scenarios:
432Wh/mile - with rounding this could be between (419 to 446Wh/mile)
442Wh/mile - with rounding this could be between (428 to 456Wh/mile)
414Wh/mile - with rounding this could be between (406 to 422Wh/mile)
423Wh/mile - with rounding this could be between (415 to 432Wh/mile)
The average of these comes to 428Wh/mile or between (417 to 439Wh/mile)

Based upon available data, that is my best guess.

These Wh/Mile seem very realistic. I have just under 40k miles on my Model S, it is lighter and I have to assume will be a better drag coefficient (.24) then the R1T and R1S (estimates I have seen are between .3 and .35). I have an average of 324 Wh/Mile over the 40K. I would assume 390 - 420 Wh/mile is a solid estimate of real world driving for the R1S and R1T.

 

[DucRider]

The vast majority of owners will not be operating their vehicles in that use case. I am glad they are testing the tails, but they should have implemented a heat pump given it is existing, proven, and three times more efficient

I haven't seen them release any details that they will not have a heat pump and rely solely on resistance. Link?

 

[mkennedy1996]

I just hope they aren’t reaching for the 21’s to be right over the 300 mark with minimal to no buffer. We know that in the first 50k or so we will see 2-5% degradation. That is why I am concerned that they’ve come out with the pack being less than 135kwh

There are a number of factors that are going to cut into the published EPA range.
1. Wheels: Could be as much as 10% range loss going from 21" to 22" based upon the difference with Teslas

2. Driving efficiency: These are high performance vehicles with 0-60 in the low 3sec. However, the EPA test is quite different: The city portion involves 18 stops over 7.5 miles at an average speed of 20 mph. Acceleration following a standing stop is done at a leisurely pace equivalent to a 0–60 time of 18 seconds. The highway cycle is 10.3 miles at an average speed of 48 mph. If you use the performance, you will see a lower range. My average over four Teslas is 80% of rated range is typical. Tesla overestimates range so I hope the R1S will not be this bad.

3. HVAC and Heat: These impact range. Heat can be devastating to range. Hopefully, they have a heat pump for cabin heating in addition to their creative method of heating the pack.

4. Battery degradation: On three of my Teslas, degradation has been: 2.2%, 2.7% and 2.9% per 10,000 miles driven.

So use 21" wheels, drive slow and accelerate like a grandma (no offense grandma), don't use the heat/HVAC and don't tow or have a rooftop carrier and you'll get the rated range on day 1. It will steadily decline over time.

 

[DuckTruck]

I didn't realize that! Just googled though & watched his config video (for anyone else considering doing the same, don't waste your time).

I think it will be very interesting to see what Sandy has to say. Now I just want to know when he placed his preorder so I can get an idea of where he stands in line to get his truck!

It hurts enough to think of all the vehicles destroyed in the NHTSA crash testing for the NCAP, but the thought of a perfectly fine Rivian rolling off the line, only to be torn apart, is a Stephen Kingish type of horror. I can hear it now: “Whew! What a journey! After a decade of incubation and finally leaving the Mothership, I wonder who’s here to raise and nurture and enjoy me? WHAT!!! Sandy?! Noooooo!!!”

On a serious note, I seem to remember hearing that when Sandy does his magic, the manufacturer is unaware of which vehicle will be sacrificed. It was said this must be the case to prevent a manufacturer from cherrypicking the vehicle being evaluated. I’m guessing Sandy’s method includes an early, albeit disguised order. I hope he didn’t pay extra for those blackout wheels!

Sandy, if you’re reading this, I’ll take one for the team and help you by testing and then destroying the Camp Kitchen to save you the time and effort. If you’re uncertain of my abilities to handle the job, message me and I’ll forward several pictures of how well I’ve done in destroying my own kitchen. I’ll also include the shipping address.

Any lessons learned by Sandy will certainly benefit orders built-out somewhere well down the road, but that is the nature of nature. While the early bird may get the worm, it’s the second mouse that gets the cheese.

 

[stephenheuer]

The vast majority of owners will not be operating their vehicles in that use case. I am glad they are testing the tails, but they should have implemented a heat pump given it is existing, proven, and three times more efficient

In Minneapolis, MN we had negative F temps for two weeks straight in February with lows hitting -20F and feels like temps diving below -30F. February is a cold month for us.

 

[Rivianmd]

I haven't seen them release any details that they will not have a heat pump and rely solely on resistance. Link?

I asked CS months ago and it was confirmed by someone else that asked as well. Like most here I am super excited about owning a Rivian; however, I have a very specific trip distance that I want to make here in the mid Atlantic and three hundred miles is the minimum needed to account for this specific trip in a R1S with a family of five, other cargo, winter conditions, and an elevation change of ~2500 feet. I will be disappointed if I can’t follow through on a purchase because I am not confident int the long-term range factoring in battery degradation. The heat pump may seem minor in the scheme of things, but this particular decision makes me question their overall thought process. Like all, can’t wait for more info. I assume they are monitoring these forums too...hopefully this is making it into the feedback loop.

 

[mkennedy1996]

I asked CS months ago and it was confirmed by someone else that asked as well.

To confirm, you were told heat strips and NO heat pump? If so, I hope that has changed as the development has continued.

 

[Rivianmd]

To confirm, you were told heat strips and NO heat pump? If so, I hope that has changed as the development has continued.

Hello again Eric,

Thank you for waiting patiently while I researched your question further. Rivian vehicles do not come equipped with heat pumps. Instead, the R1S and R1T feature an HVAC system with quad-zone temperature control for adjustable cabin comfort. These are, of course, tested for extreme conditions!

I hope that this helped! Please let us know if you have further questions.

Have an adventurous day,
Katy

8 a.m. to 8 p.m. CST - M-F
Closed - Sa-Su

 

[electruck]

The vast majority of owners will not be operating their vehicles in that use case. I am glad they are testing the tails, but they should have implemented a heat pump given it is existing, proven, and three times more efficient

Give that temps were recently below 0 F here in TX and that my vehicles have experienced temps of -20 F while visiting family in NE, I am very glad to know my RIvian will be able to handle those conditions and not have to remain parked in single digit or lower temps.

Rivian has recently stated they they will be drawing heat from the traction system (inverter and motors) to warm the battery pack but we don't know how else they might be sharing heat between the 3 different thermal control loops. Perhaps best to let Rivian do what they do best and wait to see the results before passing judgement.

Richard Farquhar: There are three thermal control loops to manage the heat energy in the drive unit assemblies, the battery, and the passenger cabin.

 

[davrow_R1T]

Perhaps best to let Rivian do what they do best and wait to see the results before passing judgement.

Where's the fun in that?

 

[Rivianmd]

Give that temps were recently below 0 F here in TX and that my vehicles have experienced temps of -20 F while visiting family in NE, I am very glad to know my RIvian will be able to handle those conditions and not have to remain parked in single digit or lower temps.

Rivian has recently stated they they will be drawing heat from the traction system (inverter and motors) to warm the battery pack but we don't know how else they might be sharing heat between the 3 different thermal control loops. Perhaps best to let Rivian do what they do best and wait to see the results before passing judgement.

Jut creating dialogue - and I’ve reviewed the HVAC patent which is available online. If Rivian has come up with something as efficient as a heat pump concept I’ll stand corrected. I haven’t seen any patents which would suggest this. When driving the vehicle after a certain amount of time waste heat from the motors and inverter could absolutely help warm the battery and cabin, but from my limited understanding when they say they will use the motor and inverter to keep the battery at + 14 F (while parked) they are relying on resistance which is 100% efficient. I just don’t get why they wouldn’t employ a heat pump. I really hope they over deliver on range, both EPA and real world. I guess we’ll wait and see.

 

[DucRider]

I just don’t get why they wouldn’t employ a heat pump.

Cost and complexity come to mind.
They will have to have resistance cabin heating available with or without a heat pump. The Rivian is designed to be used in places and under conditions in which a heat pump just won't cut it.
Also, the additional kWh usage of resistance vs heat pump (varies based on heat pump specs/operating window) have a lower mileage hit in an inefficient EV. Fewer miles/kWh means less range lost when heating. But the Tesla S/X have used resistive and recapture (inverter, etc) since their inception (until the recent refresh?) and the Model 3 only got a heat pump recently.

 

[thrill]

Jut creating dialogue - and I’ve reviewed the HVAC patent which is available online. If Rivian has come up with something as efficient as a heat pump concept I’ll stand corrected. I haven’t seen any patents which would suggest this. When driving the vehicle after a certain amount of time waste heat from the motors and inverter could absolutely help warm the battery and cabin, but from my limited understanding when they say they will use the motor and inverter to keep the battery at + 14 F (while parked) they are relying on resistance which is 100% efficient. I just don’t get why they wouldn’t employ a heat pump. I really hope they over deliver on range, both EPA and real world. I guess we’ll wait and see.

There are things we don't know about the Rivians yet (in case no one has noticed), but several factors come to mind. Heat pumps are most efficient when there is a good source of heat to move around (hence houses really gaining from them with by up to 3x because of the steady state temp of the ground). VW said heat pumps gave them about 15% improvement until the outside temp hit freezing and then it dropped off significantly, and Rivian's desire to have a minus 40 degree capable system would certainly mean a different design approach. There's three general sources of EV wasted heat - the battery itself, the power control electronics, and the motor's windings and iron in the steel. Rivan hinted they are pulling heat from the motor (I can't find the source of that at the moment - was it the video?) even when sitting still - I wonder if that was a simplification that also meant the power electronics. Anyway, to move that heat around will require something equivalent to a heat pump, and I'd guess it'd be tied into the fluid used to manage the battery. You could do it by moving warm air with a fan, but that'd be less efficient and they need fluid to keep the battery healthy anyway.

 

[mkennedy1996]

Seems reasonable - so if we take 428Wh the usable pack size would need to be at least ~128.5Kwh. If you assume they will have a buffer this gets us right back to 135 pack size.

My theory on this is that the pack size has not changed. Since the usable battery Kwh will be less than the total capacity, I submit that they are just being careful by dropping the actual size in the description (and giving the explanation that it will be slightly less than the previously published 135Kwh), which accounts for the buffer.

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