Lead foot driving

[Kachook]

As someone who has never owned an EV before, I realize that I had not considered my driving habits when thinking about the large v max pack. How much range would one lose if he/she averaged 75-80 on the Highway? I’m not as concerned about my daily commute as I’ll be plugging in every night. I’m thinking more about long distance trips. I realize the R1S is not the most aerodynamic of vehicles at least to the naked eye. Thoughts? If the 135 kw is supposed to do 305 (just making up a number), if I’m going 75 with three adults, two kids and thr A/C cranked, what am I really looking at? 220 miles per charge?

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[EVSport7]

https://www.caranddriver.com/shopping-advice/a32603216/ev-range-explained/

I like that Car and Driver and other sites do tests like this, but just based off of what other cars get and the Rivian seems more high output vs high efficiency, I'd say that low or less if I had to guess

 

[Smithery]

As someone who has never owned an EV before, I realize that I had not considered my driving habits when thinking about the large v max pack. How much range would one lose if he/she averaged 75-80 on the Highway?

My Model X 100D has its estimated range based off of an efficiency of 333wh/mi.

And if I set the cruise control at 65mph on flat road with moderate weather, I get in that ballpark - I've seen sustained 320 wh/mi occasionally, but also see 340 wh/mi in that same scenario.

We just went on vacation last week. A 185mi road trip.

Weather was moderate, and 90% of it freeway conditions. Majority flat, with some minor to moderate elevation changes. With the cruise control set at 80mph, energy usage would hold steady at ~400 wh/mi, and overall average for the trip was ~420 wh/mi (Hill climbing, a little morning heater usage, etc)

Do the math - And that's about a 25% range loss from indicated at 65mph, which is why we're going into our max pack assuming a realistic ~300mi instead of 400mi for road trips.

We're ready to be surprised, of course.

 

[Big_Ike]

As someone who has never owned an EV before, I realize that I had not considered my driving habits when thinking about the large v max pack. How much range would one lose if he/she averaged 75-80 on the Highway? I’m not as concerned about my daily commute as I’ll be plugging in every night. I’m thinking more about long distance trips. I realize the R1S is not the most aerodynamic of vehicles at least to the naked eye. Thoughts? If the 135 kw is supposed to do 305 (just making up a number), if I’m going 75 with three adults, two kids and thr A/C cranked, what am I really looking at? 220 miles per charge?

For me, owning EV's has really driven home all of the lessons I learned in physics - especially drag as a function of speed - or range loss as a function of speed. For me, on long range trips, the question is, "what's my most efficient travel speed and can my ego handle it?" Or will I endure longer charge times to beat everyone on the highway as I drive?
As my late father would say, "You're egomaniacal!"
He was right, I am... So I endure the longer charge times and suffer the lessons of physics...

 

[slawwach]

if I’m going 75 with three adults, two kids and thr A/C cranked, what am I really looking at? 220 miles per charge?

I don't know of course, but if I had to guess I would say 220 sounds about right.

You should also take into consideration that you will have 100% of charge at your disposal only on the first leg of the trip. After that charging to 100% will be too slow, so you will probably operate in 10%-80% range

 

[ATL_Canes]

For me, owning EV's has really driven home all of the lessons I learned in physics - especially drag as a function of speed - or range loss as a function of speed. For me, on long range trips, the question is, "what's my most efficient travel speed and can my ego handle it?" Or will I endure longer charge times to beat everyone on the highway as I drive?
As my late father would say, "You're egomaniacal!"
He was right, I am... So I endure the longer charge times and suffer the lessons of physics...

I have a similar debate when I’m driving. One “trick” I started using was sliding in behind a semi for stretches on the highway, which noticeably impacted range in a good way.

 

[Ladiver]

I have a similar debate when I’m driving. One “trick” I started using was sliding in behind a semi for stretches on the highway, which noticeably impacted range in a good way.

I have done this on occasion too. But, as someone who regularly tows a 38' fifth wheel, please pop out every once in a while so the driver knows that you are there. Most (if not all) of them don't have cameras or any other way of seeing directly behind them.

 

[Lil'O Annie]

On long trips, when you will be stopping for fast charging, you need to remember that the charging rate drops dramatically after 80% full. All EVs do this to protect the batteries. So, don't think of having a full battery after every charge stop. You are better off, charging-time-wise, planning the trip around a max 80% battery charge or less. Unlike stopping for ICE fuel, you don't think about "filling the tank" when you stop, you think more along the lines of getting enough to get to the next DCFC with some buffer to cover unexpected conditions like weather, head winds, hills. Until there are DCFCs on every corner like gas stations, there is more planning involved.

 

[ajdelange]

My Model X 100D has its estimated range based off of an efficiency of 333wh/mi.

And if I set the cruise control at 65mph on flat road with moderate weather, I get in that ballpark - I've seen sustained 320 wh/mi occasionally, but also see 340 wh/mi in that same scenario.

Interesting. My XLR+ is rated at 282 and I sometimes get better than that on a roadtrip that involves lots of freeway and sometimes I get worse. Looking at my last 10 freeway drives I did as well as 162 Wh/mi and as poorly as 383 Wh/mi with a median of 288.5. The average average (that is the average of the averages) speed was 55.2 and the average peak speed was 78.9. IOW largely freeway but with some state highway and some slowdowns on the freeway. I general, of course it is virtually impossible to separate out the effects of any of the variables which determine consumption. I used the median for the consumption rather than the mean because of the 383 Wh/mi outlier. The second largest consumption was 310. The reason that consumption was so high on this trip was that there was slush on the road. This is a killer.

Weather was moderate, and 90% of it freeway conditions. Majority flat, with some minor to moderate elevation changes. With the cruise control set at 80mph, energy usage would hold steady at ~400 wh/mi, and overall average for the trip was ~420 wh/mi (Hill climbing, a little morning heater usage, etc)

Relative to 333 those numbers represent increases of 20 - 26% corresponding to range reductions down to 83 to 79%. I think those numbers are entirely reasonable. With the Rivians, especially the truck, I think the degradations may turn out to be a little more than this because they are going to have a large Cd and a larger frontal area than the X which is rather bullet shaped.

 

[Kachook]

I have a similar debate when I’m driving. One “trick” I started using was sliding in behind a semi for stretches on the highway, which noticeably impacted range in a good way.

So, I've heard of hypermiling. One question - TX roads are horrible and there is so much windshield damage here because of a variety of things including these big trucks. How much windshield damage do you expect when doing that? For reference purposes, State Farm used to cover windshield repair/replacement in TX, but stopped a few years ago because of it. Thank you!

 

[Kachook]

Interesting. My XLR+ is rated at 282 and I sometimes get better than that on a roadtrip that involves lots of freeway and sometimes I get worse. Looking at my last 10 freeway drives I did as well as 162 Wh/mi and as poorly as 383 Wh/mi with a median of 288.5. The average average (that is the average of the averages) speed was 55.2 and the average peak speed was 78.9. IOW largely freeway but with some state highway and some slowdowns on the freeway. I general, of course it is virtually impossible to separate out the effects of any of the variables which determine consumption. I used the median for the consumption rather than the mean because of the 383 Wh/mi outlier. The second largest consumption was 310. The reason that consumption was so high on this trip was that there was slush on the road. This is a killer.

Relative to 333 those numbers represent increases of 20 - 26% corresponding to range reductions down to 83 to 79%. I think those numbers are entirely reasonable. With the Rivians, especially the truck, I think the degradations may turn out to be a little more than this because they are going to have a large Cd and a larger frontal area than the X which is rather bullet shaped.

This is helpful. I have deposits on both the R1S and the X. The X ends up being about $10k more expensive. I'm a late reservation holder for the R1S (4/2021). So, by the time my turn comes around, maybe Q3 of 2022, the max pack will be available for the R1S. Basically, with the max pack, I'd be at the same price as the X. First world problems, I know.

 

[Rivianmd]

I too am worried whether the large pack will be enough for a certain use case I have where I want to make a straight shot at about 160 miles and regularly drive 75-80 all highway today. In addition, it will have an elevation gain and we often travel the route during winter months. My hope is that the sheer size of the pack helps with heat during the winter months and the R1S has better aero than we think. It seems the e tron does fairly well and is more representative of size/aero than MX. I guess we’ll find out soon….

 

[ajdelange]

I too am worried whether the large pack will be enough for a certain use case I have where I want to make a straight shot at about 160 miles and regularly drive 75-80 all highway today. In addition, it will have an elevation gain and we often travel the route during winter months.

Nominally everything looks good. The 20% range penalty that goes with fast driving leaves you with 0.8*400 = 320 miles nominal range. Another 20% loss for wet roads gets you down to 0.8*320 = 256. Another 20% for elevation would have you at 212. And if you adopt a policy of using only 80% of the battery you still have 170. So you are in pretty good shape. Now throw in a 20 kt headwind and you are in trouble. But the odds of all these things conspiring against you at one is small - but, f course, there are perfect storms.

Keep in mind that the car is going to give you good information about what is happening in real time. If you pay attention to this information you will not get caught out. If it looks as if you are going to fall short the first thing to do is slow down. Then turn off the cabin heat (use the seat heaters). Then turn them off too and use a blanket. Or just stop for a supplementary charge. Of course you don't want to have to do any of those things and most of the time you won't have to.

My hope is that the sheer size of the pack helps with heat during the winter months and the R1S has better aero than we think. It seems the e tron does fairly well and is more representative of size/aero than MX. I guess we’ll find out soon….

That's the key thing to note. You will quickly learn, in most cases, how to manage range and battery. There are some hopeless cases that do manage to run out of charge. They shouldn't be driving BEV.

 

[Rivianmd]

Nominally everything looks good. The 20% range penalty that goes with fast driving leaves you with 0.8*400 = 320 miles nominal range. Another 20% loss for wet roads gets you down to 0.8*320 = 256. Another 20% for elevation would have you at 212. And if you adopt a policy of using only 80% of the battery you still have 170. So you are in pretty good shape. Now throw in a 20 kt headwind and you are in trouble. But the odds of all these things conspiring against you at one is small - but, f course, there are perfect storms.

Keep in mind that the car is going to give you good information about what is happening in real time. If you pay attention to this information you will not get caught out. If it looks as if you are going to fall short the first thing to do is slow down. Then turn off the cabin heat (use the seat heaters). Then turn them off too and use a blanket. Or just stop for a supplementary charge. Of course you don't want to have to do any of those things and most of the time you won't have to.

That's the key thing to note. You will quickly learn, in most cases, how to manage range and battery. There are some hopeless cases that do manage to run out of charge. They shouldn't be driving BEV.

My only problem is I am looking at the large pack…not the max. I feel reasonably good that if the S comes back at 315+ epa that it will work for 99%. But it will be close in winter months with teens weather a d headwinds

 

[PAFDenver]

We just went on vacation last week. A 185mph road trip.

185MPH!?!?! Now THAT will really affect your range!

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