Battery Size and other speculation from the EPA numbers

[DucRider]

Some of this is scattered in other threads, but thought I'd start a new one.

From the EPA data released, it looks like the nominal battery capacity is 144 kWh on both the R1T & R1S (400V nominal * 360 Ah)

It looks like the useable/available capacity is very close to the original 135 kWh designation. The efficiency numbers show that the R1S took 153.0 kWh to fully recharge on both the City and Hwy tests (measured from the plug), and the R1T 150.6 kWh on the City portion and 150.5 kWh on the Hwy.

Charger efficiency is usually pretty darn close to 90%
153 kWh * 90% = 137.7 kWh
150.5 kWh * 90% = 135.5 kWh

Derating from raw results:
The R1S uses a factor of .70, the default value whether using the 2 or 5 cycle tests
The R1T uses a factor of .72, which needs to be justified by "real world" testing data if using the 5 cycle test

The better MPGe of the R1T vs the R1S could be attributed to either the increased energy needed to charge the R1S, the lower derating of the R1T or - more likely - both of these factors.

https://www.fueleconomy.gov/feg/epadata/22data.zip

Once the actual test documents are available, a little more insight can be gleaned.

From those that attended the "First Drive" event, it was indicated that more range and battery capacity could be made available to those "being good". This implies that battery capacity is not a constant and that could have been part of the holdup with official EPA numbers. There is nothing in their test procedures that allows for a variable battery capacity. They likely had to settle on an "as shipped" configuration?

Did they need to open up a bit more of the R1S battery to give it more range than the R1T since that was what they have promised? Did the EPA test yield different results that what they predicted on paper?

Let the speculation continue.

Sponsored

 

[Kmann1994]

FWIW, Rivian already confirmed range will be increasing via OTA updates:

Knowing Rivian's pace, I'd expect this to happen at least once in the first year of production. I'm excited that I'm taking delivery in Q4 2022.

 

[Autolycus]

Some of this is scattered in other threads, but thought I'd start a new one.

From the EPA data released, it looks like the nominal battery capacity is 144 kWh on both the R1T & R1S (400V nominal * 360 Ah)

It looks like the useable/available capacity is very close to the original 135 kWh designation. The efficiency numbers show that the R1S took 153.0 kWh to fully recharge on both the City and Hwy tests (measured from the plug), and the R1T 150.6 kWh on the City portion and 150.5 kWh on the Hwy.

Charger efficiency is usually pretty darn close to 90%
153 kWh * 90% = 137.7 kWh
150.5 kWh * 90% = 135.5 kWh

Ahh, duh. My post in the other thread was completely ignoring the fact that the EPA counts everything as from the wall, not direct from the battery! That said, unless someone else beats me to it, I'm going to have to crunch some numbers on the pack, module, and cell capacities that might get that that nominal pack capacity. And possibly some more research on what Samsung SDI has out there.

 

[RWerksman]

FWIW, Rivian already confirmed range will be increasing via OTA updates:

Never, ever buy a shipping product on the promise of future functionality or updates.

This could easily end up in the same pile as the 180 degree tailgate, electrochromic roof or Lidar.

 

[LordUlhtred]

Never, ever buy a shipping product on the promise of future functionality or updates.

complete agree. I have a Tesla model 3 from 2018. Tesla later “upgraded“ the rated range from 315 to 325 or something close to that. I never saw any of that increase.

 

[Kmann1994]

Never, ever buy a shipping product on the promise of future functionality or updates.

This could easily end up in the same pile as the 180 degree tailgate, electrochromic roof or Lidar.

Yeah for sure, I agree with that. I was just saying that at least they immediately said that, which I thought was pretty impressive.

I'm getting the Max Pack anyways.

 

[LordUlhtred]

300 miles is more than enough for most of the trips. Even for most of road trips based on my experience with model 3. I personally reserved max pack, like you, to add extra convenience and also to be able to do cross country road trips with gears.

 

[SeaGeo]

From those that attended the "First Drive" event, it was indicated that more range and battery capacity could be made available to those "being good". This implies that battery capacity is not a constant and that could have been part of the holdup with official EPA numbers. There is nothing in their test procedures that allows for a variable battery capacity. They likely had to settle on an "as shipped" configuration?

Are you thinking the nominal range reported to the EPA isn't constant, or the usable? My hunch for this has been that they plan to keep provide people say... 135 of the 144 kwh capacity to start. And then based on observed usage and degradation, it would keep the buffer over time to try and protect the vehicle from degradation if you're hard on it, or grant some people additional usable capacity based on being pretty easy on the battery. I think the question is whether that 144 is the true nominal capacity, or just what Rivian is reporting (as you implied). If they're only pulling off the difference between 135 and 144, that's not a lot of room for improvement while maintaining some buffer.

 

[DucRider]

Are you thinking the nominal range reported to the EPA isn't constant, or the usable? My hunch for this has been that they plan to keep provide people say... 135 of the 144 kwh capacity to start. And then based on observed usage and degradation, it would keep the buffer over time to try and protect the vehicle from degradation if you're hard on it, or grant some people additional usable capacity based on being pretty easy on the battery. I think the question is whether that 144 is the true nominal capacity, or just what Rivian is reporting (as you implied). If they're only pulling off the difference between 135 and 144, that's not a lot of room for improvement while maintaining some buffer.

It's fairly certain that the useable number is ~135 kWh.
Rated or nominal capacity is a guess, but the numbers make sense.

Rivian originally announced a battery architecture with 108 cells in series. Modules were made up of two 432 cell layers, so each module was 108s 8p.
The "Large" (135 kWh) pack had 9 modules and was thus 108s 72p.

2018 specs on a Samsung 21700 50e (2) show a 3.63 V (nominal) and 4.9 Ah per cell
Plugging those numbers in would yield a pack of 392 V and 353 Ah (138 kWh)

Rivian has stated they would be using a custom cell, so probably a little different than the 50e.

If we take a theoretical cell with a nominal voltage of 3.7 and a 5.0 Ah rating, then plug those numbers in and:
400V and 360 Ah (144 kWh) which matches the EPA specs

 

[SANZC02]

It's fairly certain that the useable number is ~135 kWh.
Rated or nominal capacity is a guess, but the numbers make sense.

Rivian originally announced a battery architecture with 108 cells in series. Modules were made up of two 432 cell layers, so each module was 108s 8p.
The "Large" (135 kWh) pack had 9 modules and was thus 108s 72p.

2018 specs on a Samsung 21700 50e (2) show a 3.63 V (nominal) and 4.9 Ah per cell
Plugging those numbers in would yield a pack of 392 V and 353 Ah (138 kWh)

Rivian has stated they would be using a custom cell, so probably a little different than the 50e.

If we take a theoretical cell with a nominal voltage of 3.7 and a 5.0 Ah rating, then plug those numbers in and:
400V and 360 Ah (144 kWh) which matches the EPA specs

Gary,

What am I missing, the EPA says 49kw/100 miles. That is 490 watts per mile.

The 316 range on a 135 kw battery = 427 watts per mile.

edit: Never mind, I reread your first post in this thread, they are factoring in the efficiency loss when charging measured from the wall. That gives overall efficiency and cost as opposed to range.

 

[Babbuino]

Gary,

What am I missing, the EPA says 49kw/100 miles. That is 490 watts per mile.

The 316 range on a 135 kw battery = 427 watts per mile.

edit: Never mind, I reread your first post in this thread, they are factoring in the efficiency loss when charging measured from the wall. That gives overall efficiency and cost as opposed to range.

Looks like MT also has similar I formation about the pack
"The 135-kWh pack (133 kWh usable) is small only in regard to what the company wants to offer in the future; it's the biggest on the market, at least until the gargantuan 200-kWh pack in the GMC Hummer EV shows up."
https://www.google.com/amp/s/www.motortrend.com/news/2022-rivian-r1t-r1s-epa-ev-range/amp

 

[SeaGeo]

Gary,

What am I missing, the EPA says 49kw/100 miles. That is 490 watts per mile.

The 316 range on a 135 kw battery = 427 watts per mile.

edit: Never mind, I reread your first post in this thread, they are factoring in the efficiency loss when charging measured from the wall. That gives overall efficiency and cost as opposed to range.

The EPA communication on efficiency and range is a hot mess isn't it?

 

[AdamsFan1983]

I’ve seen some posts here and there that they tested the r1t with a 1500 # payload. Can anyone confirm?

 

[Attesan997]

I’ve seen some posts here and there that they tested the r1t with a 1500 # payload. Can anyone confirm?

If they used the "F150 Lightning" play as I call it, it wouldn't be known until a media outlet lets it be known. Or Rivian just comes out and says it...

 

[Autolycus]

It's fairly certain that the useable number is ~135 kWh.
Rated or nominal capacity is a guess, but the numbers make sense.

Rivian originally announced a battery architecture with 108 cells in series. Modules were made up of two 432 cell layers, so each module was 108s 8p.
The "Large" (135 kWh) pack had 9 modules and was thus 108s 72p.

2018 specs on a Samsung 21700 50e (2) show a 3.63 V (nominal) and 4.9 Ah per cell
Plugging those numbers in would yield a pack of 392 V and 353 Ah (138 kWh)

Rivian has stated they would be using a custom cell, so probably a little different than the 50e.

If we take a theoretical cell with a nominal voltage of 3.7 and a 5.0 Ah rating, then plug those numbers in and:
400V and 360 Ah (144 kWh) which matches the EPA specs

Samsung SDI's 50G cell is their 91% nickel chemistry that was first produced in May 2019. Rivian's cells would certainly be more in line with 50G than 50E. Could possibly be using an even newer chemistry though.

Here are the specs for the 50G from a trade show booth:

The published spec sheets [distributed to buyers] just show the same "minimum capacity" of 4.9 Ah, but I suspect actual capacity is a little higher.

Sponsored