Are you excited or dissapointed?

[Babbuino]

But it does mean that if you want to get the full tax credit, that you'll need to try and get one of the first 200k vehicles, knowing that Amazon is trying to order 100k of them (again no knowing the timing of those deliveries). Hopefully the configurator will shed some light on final pricing based on production and delivery for specific models and configurations.

I believe I read that 10K by the end of 2022 and the full 100K by 2030.

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[skyote]

Who in his right mind wants the smaller battery if you can afford the larger one thus the reason for offering the smaller battery at all is to make the truck affordable to those who can't throw money around as if it grows on trees.

Me, and I can assure you I am of sound mind. I can afford the 180, but have wanted the 135 since the beginning after rationalizing. This is for 2 main reasons:

1) 135 is plenty for 98% of my usage. Also, looking at the negligible time differences in even longer road trips that some members here have posted, I'm now 100% confident that the 135 pack is plenty with current charging infrastructure (and that will only improve in the coming years).

2) I do plan to take my Rivian off road, and will encounter both mud & sand. From many years of off road experience, I know how much difference even a couple hundred pounds of extra weight can make. I don't want that extra battery weight in soft surface conditions, or even climbs/descents.

 

[ajdelange]

Me, and I can assure you I am of sound mind.

I would have to check with my wife before I made that claim but you certainly seem so in your postings here.

1) 135 is plenty for 98% of my usage. Also, looking at the negligible time differences in even longer road trips that some members here have posted, I'm now 100% confident that the 135 pack is plenty.

Don't doubt that but I have a question for you. Were the 180 pack available at the same price or at such as small premium as to be in the noise, would you reject it in favor of the smaller? Read on before answering.

2) I do plan to take my Rivian off road, and will encounter both mud & sand. From many years of off road experience, I know how much difference even a couple hundred pounds of extra weight can make. I don't want that extra battery weight in soft surface conditions.

Have you considered that the four independent motors and in particular the ability of electronically controlled motors to manage slip optimally might overcome the effects of the extra weight?

Note: I'm not trying to sell you on the 180kWh battery. Not much point in that as you can't get it anyway!

 

[skyote]

Were the 180 pack available at the same price or at such as small premium as to be in the noise, would you reject it in favor of the smaller? Read on before answering.

135 is still a better fit for me. In ~5 years, I expect battery technology to advance enough where additional range won't carry the same financial and weight "tax" that it does currently.

Have you considered that the four independent motors and in particular the ability of electronically controlled motors to manage slip optimally might overcome the effects of the extra weight?

Yes. The 4 independent motors is a huge selling point for me versus traditional differentials. Even the 135 pack is SIGNIFICANTLY heavier than my Jeeps (close to 50%, +/- 2K lbs), and that alone is a ton of weight...literally & figuratively.

 

[DucRider]

Here comes a bunch more engineering stuff which probably will be of no interest to most but at the end there are some practical recommendations derived from the engineering considerations. Skip the geek stuff if you like.


I'm putting the link to the entire spec in here as this table out of context is clearly misleading: https://www.dnkpower.com/wp-content/uploads/2019/02/LG-INR21700-M50-Datasheet.pdf though I must say that this spec is about as clear as the Seoul street numbering system.

The key thing to understand here is that all the energy you put into the battery is there largely independent of its temperature. Where would it go? The thing that changes with temperature is the cells' internal impedances and they change dramatically. The specs on this cell suggest they change by a factor of as much as 30 between room temperature and -10 °C. This means that if you want to get all the energy out when the battery is cold you must discharge the cell slowly in order to keep I^2R losses down. My earlier comment about how confusing this spec is starts with the fact that they never state the capacity of the battery! In discussing charging and discharging they reveal that 0.3C = 1.455 A from which we can, of course, calculate that C = 4.850 Ah. The data in the table pertain to a discharge rate of 0.2C = 0.99A - call it 1 A for simplicity. The stated DC impedance for this cell is 30 mΩ at 25 °C so that if discharged at 0.2C the I^2R loss is 30 mW and as the discharge time is clearly 5 hrs at 0.2C the energy lost to heat would be 0.150 Wh. The minimum energy capacity of this cell is stated as 17.6 Wh and the I^2R losses amount to 0.8% at 25 °C so that recovery at that temperature is 99.2% - not 100% as the chart states. Now turning attention to the -10°C entry the number is 70% preceded by a greater than or equal symbol. This means that the manufacturer is guaranteeing I^2R loss of at worst 30%. This is commensurate with an increase in cell internal impedance by a factor of about 40 due to ion mobility - not, I gather, an atypical number at low temperature. Thus the spec, if you consider all of it, does not present any surprises.

Now if one discharges at 0.1C instead of 0.2C the current is halved and the I^2R loss goes down by a factor of 4. Instead of losing, at worst, 30% of the available energy to heating one would expect to lose 7%.

PRACTICAL CONSIDERATIONS

Battery capacity doesn't decrease with temperature but access to it does. Is there anything we can do? Yes and the obvious thing to do is heat the battery. This, of course, takes energy. Clearly the goal is to conserve range and so, equally clearly, we want to depart on a cold weather journey with a warm battery if that is possible. Keeping the vehicle in a warm garage is one method. Arranging home charging to finish just before departure is another (uses the heat dissipated in the battery internal resistance during charging). These may not be possible in which case the heat must come either from the battery perhaps supplemented by a heat pump if the vehicle has one. The design should definitely capture waste heat from inverter/rectifiers and motors and route it back to the battery.

Bottom line is that if you set out with a cold battery you will have to give up range until it is warm. And, of course, it must be kept warm. Keeping it warm may deduct from range (too cold for heat pump).

Until the battery warms up, keep your foot off the skinny pedal to the extent possible. With a 100 kWh battery 0.2C is about 20 kW and 0.1C with 1/4 the energy loss to I^2R is 10 kW. Or you may choose to adopt the opposite approach and stomp it reasoning that the higher dissipation will warm the battery faster.

Summary: The battery doesn't contain any less energy at colder temperature but you will have to give up some range because some of that battery energy will have to go to warm the battery.

You used up a whole lot of word to confirm that range is lower when the battery is cold because it cannot supply as many Wh at lower temps (but it doesn't "go away" permanently).
There is a newer (2018) version of the cell/spec sheet than the one you referenced:
https://www.batteryspace.com/prod-specs/11514.pdf
If you want some detailed independent testing data of a single cell:
https://endless-sphere.com/forums/viewtopic.php?t=101716

lots of detail that @ajdelange will love

 

[ajdelange]

OK. It seems that you are mostly concerned about weight but that cost is still a factor. I can't do much about the latter but I can point out that the thrust produced by a wheel is

F = mu*sx*m*g*cos(a)

in which mu is a constant (for a given substrate) which will be higher on bitumen than it will be in mud, m*g is the weight of the vehicle and alpha is the angle of the grade wrt the horizontal. -1 < sx < 1 is the slip. This formula applies in the linear region |sx| < 0.1. Outside that increasing slip further does not increase torque. The point of this is that if you are in gloop the way to get out is to increase the weight and the slip but to keep |sx| < 0.1. The controller can set sx any where you want it to be. Thus, with the R1T the extra weight of a heavier pack is ostensibly an advantage - not a detriment.

Now this is the theoretical guy sitting at his desk speaking. Not someone who has got a truck stuck in mud, sand or snow. But when I have been my strategy has been to go easy on the throttle (control sx) which doesn't always work or increase mu (by using sand with snow, boards with sand etc. I have never found taking stuff out of the truck to help.

 

[ajdelange]

You used up a whole lot of word to confirm that range is lower when the battery is cold

I'm not taking issue with that. Range is also lower because the cabin is cold. What I took issue with was:

Since the kWh rating of a pack is actually a variable that changes with temperature

Apparently there are no pack ratings any more but if there were one it would be the amount of energy extracted at some discharge rate at some temperature and therefore a constant not a variable. The kWh rating would be the kWh rating. How much of that you could expect to get would depend on how fast you discharged it (external impedance) and how hot/cold it was (internal impedance).

...because it cannot supply as many Wh at lower temps

It can supply just as many Wh cold as when hot but you must take them at a lower rate. The amount lost to higher rate goes as the square of the rate.

There is a newer (2018) version of the cell/spec sheet than the one you referenced:

Not much help here as they took the DC internal impedance number out. But thanks for posting nonetheless. I downloaded it too.

 

[ajdelange]

... and there is currently only ONE L2 (not CCS) charger on any of the routes I take. Its really a reach with the 180 kWh pack.

Remember that any 240 V outlet (outlet for electric oven, clothes dryer, welder, floor polisher, camper...) is an L2 source.

 

[azbill]

But Rivian has the real data i.e. the pre-orders. It may be that the ratio of 135 to 180 orders is way lopsided towards 135.

When I pre-ordered I simply stated that I wanted the R1T, nothing else. There was nothing in the pre-ordering that indicated battery size or any other options. So Rivian will not have that actual data until Monday, when we start to configure the vehicles. They are basically forcing the data in the direction of the smaller battery by making that the only one available next year.

I personally will stick to the larger battery and wait, because I want the right truck for me, I will not let the emotion of getting it sooner cause me to end up disappointed in the long run.

 

[ajdelange]

You know now that I think of it I don't remember specifying pack size either.

 

[Smithery]

I personally will stick to the larger battery and wait, because I want the right truck for me, I will not let the emotion of getting it sooner cause me to end up disappointed in the long run.

Holy crap, the maturity!



(Me too)

 

[cohall]

You know now that I think of it I don't remember specifying pack size either.

We definitely didn't specify battery pack during pre-order.

But, this is not a company of imbeciles. They've certainly done research among future owners on what they intend to configure. It's the only way to appropriately plan for production requirements.

My point is, your point remains relevant.

 

[DucRider]

It can supply just as many Wh cold as when hot but you must take them at a lower rate. The amount lost to higher rate goes as the square of the rate.

For any given draw >0, there will be fewer Wh available. The lower the draw, the less the impact. Driving a 6,000 lb vehicle requires a draw well above 0 (on average, I understand if you are descending a grade with a tail wind, you may actually be charging the vehicle). The batteries will supply fewer Wh when cold - all other factors being equal.

 

[aAlpine]

When I pre-ordered I simply stated that I wanted the R1T, nothing else. There was nothing in the pre-ordering that indicated battery size or any other options. So Rivian will not have that actual data until Monday, when we start to configure the vehicles. They are basically forcing the data in the direction of the smaller battery by making that the only one available next year.

I personally will stick to the larger battery and wait, because I want the right truck for me, I will not let the emotion of getting it sooner cause me to end up disappointed in the long run.

Ditto here. I'm hoping that many people go this route and they run out of 135kWh customers and start the 180kWh deliveries early. The forum poll had 61.5% of people asking for the 400 mile range, but I suppose 40% of 50k preorders is quite a lot of cars to make in the first 6 months, so maybe it's just wishful thinking on my part.

 

[GIJoe]

Rivian might have 50k preorders by now. Not sure anybody needs to worry about tax-rebates expiring before your long-time preorder-holder 180KWh trucks get done in possibly 1st quarter 2022 at the latest.

will Amazon vans count towards the company 200k?

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