good discussion here. I am wondering in addition to battery size could Rivian be also looking at the electric motor technologies that can be more efficient and keep or increase performance and provide more range?
Interesting that within hours of posting this we see that the Tesla Model S now offers EPA rating of 409 miles thus putting it ahead of Lucid and making Rivian's 300 mile early release even more of a disappointment to many. The improvement apparently comes from software tweaks.Definitely. And, as I mentioned in a previous post, the motor control algorithms plus eventual transition to higher voltage.
I love Tesla, and have one, but it’s rare to get more than 75% of range on the highway. And I mean 100-0% range, not just usable. The key to me is what is the actual range on the highway. Around town range really doesn’t matter due to charging at home. If Rivian can be more like the Taycan which easily beats its EPA range on the highway, 300 will be ok for most people. If it’s like Tesla where 75% is the norm (based on my experience) then I may want the bigger battery. Aside from the lower price, this is one reason why I am ok waiting for 2022 for the explore trim. I’d like to see some real data before making a decision.Interesting that within hours of posting this we see that the Tesla Model S now offers EPA rating of 409 miles thus putting it ahead of Lucid and making Rivian's 300 mile early release even more of a disappointment to many. The improvement apparently comes from software tweaks.
I worry a bit about some of the people posting - both on this forum and in general - expecting to get the rated range at highway speed and at all temperatures/weather conditions.The first thing an experienced BEV driver does is look at the EPA range and take 80% of it.
I agree. I usually only average about 60 or so miles on an hour on longer road trips factorin in traffic and would rarely go more than three hours without a short break. I drink a lot of coffee and have kids and a dog. After thinking about it some, I think I can do fine with the "large pack" and don't need 400+ miles range. With charging at home cover over 90% of my driving and never needing to go to a gas station that net savings in time is huge.So, before I got my Model 3 “stealth” performance, I was concerned about the approx 300 range. Around town with home charging it’s irrelevant but the occasional road trip would be my concern. What I came to realize was that my family itself has a range of only 150 to 175 miles before someone needs a bathroom or a coffee or a snack. Once I’d gotten everyone to sign on to the “we stop when we charge” logic, we made good time...and charging was just what was happening while everyone did everything else. Of course, those of you who actually make more miles on each stint will need to adjust —the logic with BEV is just different (not necessarily worse or better) as you generally want to keep the battery pack in the 20% to 80% window to stay in the fastest part of the charging curve. Driving based on the ultimate range between each charging stop is supposedly the slower way to road trip. Of course, like I said, you have to have a family that lasts that long! Can’t wait for our R1S as the kids keep getting bigger and the dog would like to come along.
The main reason I'd consider the R1S is because it is shorter. I see that as it's main advantage, not disadvantage. But then again I don't want or need 7 seats. It's impossible to spec any vehicle that's going to please everybody. Both models have what I would consider compromises to my ideal vehicle. I configured R1T, but after the wife and I see and drive them, that could change.I really wish they would just make the R1s 6 to 8 inches longer. They did it with the truck. It seems like a design flaw from day 1 to make the SUV shorter than the truck and have to compromise one of the main advantages (7 seats) to get max range
Very bad advice!Ignore the EPA ratings.
Only to those who don't understand what they represent nor, consequently, how to interpret them and use them to advantage. Now in saying this I recognize that there are many who happily drive these cars that fall into that group.They are pretty much BS.
That depends on how you drive them. I've had 2 X's now and both were, on average, very close to the EPA ratings. That didn't mean that I always got/get (I still have an X) rated consumption. As I said above, what you get depends on how, when and where you are driving. If you want to use the EPA rating information you must educate yourself as to what the effect of, say, rain is (-30 %). This is easy to do if you are numerate and impossible to do if you are, by nature or intent, innumerate.My Taycan far exceeds the EPA rating, my Audi E-tron gets almost exactly the EPA rating, and the Model X we used to have never got close.
The key word there is "about". The energy available from a battery depends on how fast it is withdrawn. If you drive fast not only do you use more Wh/mi to overcome drag (number depends on the square of the airspeed) but you lose more to warming the battery. Bit is any case the available discharge energy from the X battery is in the mid or low 90's (even though everyone knows that the X has a 100 kWh battery, nes pas?). The consumption for the 294 mile rated X was about 300 Wh/mi so with 93 kWh available discharge energy you would expect about 313 miles range. The actual available discharge energy from that version of the X was probably closer to 92 kWh for an estimated range of about 307 miles. Pretty close to the EPA rating of 294.Using real world experience and data, let's compare the R1S to a Tesla Model X (probably the closest in terms of efficiency, size, and weight). With my Model X 100D (EPA rated 295) we averaged around 0.380 kWh/mi. The Model X has a usable battery capacity of about 94kWh.
So this equals roughly 247 miles of range.[/QUPTE] If you got 247 miles you were obviously driving in parts of the envelope distant from the ones on which the EPA rating is based. You should understand that before making statements that the EPA rating are not useful.
The newer X has 351 mile EPA range and this was realized by lopping 30 wH/mi off the consumption. In my personal experience with the newer X I see about 280 Wh/mi which, gives me about 329 miles from 92 KWh of battery energy. Again, pretty close to the EPA rating for the car.Now the newer Model X has a higher EPA range, but I think some of this is just optimization of the EPA testing and not real world efficiency.
Let's say it is closer to 272 which is the rated consumption for the car. Or to 280 which is what I see. Let's also note that if you take the 351 mile EPA range and the rated consumption and put them together they tell you that the available discharge energy is 95.472. kWh.So let's say it's closer to 0.340 kWh/mi.
If you are seeing consumptions as high as this then I cannot say what it is you are doing but whatever it is it is quite dissimilar from the condtions under which the EPA measurement is made. The EPA number strives to do an impossible thing: predict performance under the conditions a typical driver can expect. I find it does so quite well. You do not but that is because your use mode is atypical. Most Tesla X drivers realize 70 - 100% "efficiency" with respect to the rated consumptions (meaning consumption of 272 - 388 Wh/mi) with average of 82% in the winter and 94 - 96% in summer)The would be roughly 276 miles of range. Now keep in mind this is an average overall with a mix of city and highway driving. When cruising at 75-80mph my Model X used 0.420-0.450 kWh/mi. So my highway range dropped to about 216 miles.
That's actually a reasonable set of assumptions that does not fit at all with the first sentence in your post. 400 may be a little optimistic but my gut feel says it's not too far off. Because of all the uncertainty attached to specification of battery "capacity" Rivian an Tesla have dropped battery size specification in their sales and labeling and now refer to the individual vehicles by their ranges. Thus the early release car is no longer the 135 kWh truck but the 300 mile truck. Nonetheless if 400 to 410 wH/mi be reasonable estimates of the rated consumption and the EPA mileage comes in at 300 then the available discharge energy in the battery pack would clearly be around 120 - 123 kWh.Now lets assume the R1S uses more energy than the Model X. It's taller, at least looks a little less aerodynamic, and probably doesn't have as much special sauce in terms of efficiency as a Tesla. So lets say worst case its 0.400 kWh/mi in mixed driving and 0.480 kWh/mi on the highway. Assuming the 135kWh battery has a usable capacity of 120kWh this would be a mixed range of 300 miles and a highway range of 250 miles.
If the battery pack architecture is required to be such that packs with nominal discharge energies of 105, 135 and 180 kWh can be built from them and that the packs can be charged from either 500 V or 920 V chargers then the largest the individual modules can be iis 3.75 kWh. In the firs place no one has said the modules have to be the same size and in the secons it's moot. Just as the early release RIT will be a 300 + mile vehicle so the ones coming later will be 400+ mile vehicles however the battery packs are configured.Now as someone stated above, if the battery modules are 15kWh,
The EPA range is calculated based on drag results from a dynamometer and then some calculations to account for aerodynamics. No data from the actual road. Show me any independent test that correlates to the EPA range ratings across multiple vehicles.Very bad advice!
Only to those who don't understand what they represent nor, consequently, how to interpret them and use them to advantage. Now in saying this I recognize that there are many who happily drive these cars that fall into that group.
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