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What is 2mi/kWh?

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Andystroh

Andystroh

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2.29 mi/kWh sounds about right. That would give a range of 309 miles.

The 2 mi/kWh seen on the left in that photo is simply the scale for the graph and should not be confused for the actual mi/kWh that vehicle is averaging. I think the OP may be looking at that and mistakenly thinking the vehicle is only getting 2 mi/kWh.
I understand the vehicle is getting the value shown below the graph, my question is only “why 2 as a baseline”? I understand it won’t always meet the EPA range, but I thought it would be more valuable to see “efficiency vs manufacturer quoted estimate” than “efficiency vs arbitrary value”. Good point above on the AT tires, if this baseline changes in a vehicle with 21” to approximately 2.3 then this would make perfect sense, since they stated lower range with the 20”. I’ll have to see if I can find any images of another baseline.
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So is the 1 Hummer EV that is roaming the streets somewhere.
Luckily heavy duty trucks don't need to be EPA rated.
 

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but I thought it would be more valuable to see “efficiency vs manufacturer quoted estimate” than “efficiency vs arbitrary value”.
This makes no sense to me. The so called "manufacturer quoted estimate" is an efficiency derived from an EPA test cycle from which your actual driving conditions will almost always deviate. It's simply a y-axis label, not a target. The point of the efficiency graph is to reflect how your driving habits and environmental conditions are impacting your efficiency over time, not reflect your efficiency relative to some hypothetical EPA test condition "baseline".
 
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Max

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They're referring to this.
1642706468772.png
If I had already received my R1S, I would start the Hyper-mile thread so people could post this image off of their R1 with the explanation on how they have beat the best 15 mile average. Of course there need to be Tire, mode, elevation change, wind, .... declaration. I am so ready to obsess about this and no R1S in sight.
 

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2 mi/kWh sounds reasonable for winter driving. I would expect consumption to be closer to 3 mi/kWh in warmer weather.
 

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2 mi/kWh sounds reasonable for winter driving. I would expect consumption to be closer to 3 mi/kWh in warmer weather.
The awesome thing on the IG post is that it says the driver was in 19 deg F going 55/60 on the interstate; pictures show this is an offroad upggraded R1t on 20ATs.

Making me happy thinking about my 240 one way road trip to the ADK mountains in winter.
 

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This makes no sense to me. The so called "manufacturer quoted estimate" is an efficiency derived from an EPA test cycle from which your actual driving conditions will almost always deviate. It's simply a y-axis label, not a target. The point of the efficiency graph is to reflect how your driving habits and environmental conditions are impacting your efficiency over time, not reflect your efficiency relative to some hypothetical EPA test condition "baseline".
Agree with you, but Rivian's graph is confusing things by emphasizing the 2mi/KWh mark not only with a dashed line but also the different shading above and below the dashed line.

One approach to grokking this graph is to ignore the dashed line and the shading and imagine the lower-left corner tagged with 0mi/kWh and the upper left tagged with a 4mi/Kwh.
 

AllInev

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Agree with you, but Rivian's graph is confusing things by emphasizing the 2mi/KWh mark not only with a dashed line but also the different shading above and below the dashed line.

One approach to grokking this graph is to ignore the dashed line and the shading and imagine the lower-left corner tagged with 0mi/kWh and the upper left tagged with a 4mi/Kwh.
Rivian R1T R1S What is 2mi/kWh? 1642706468772
 

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id guess they picked the 2 as the "baseline" because to achieve the max EPA rated rage of 314 miles you'd have to avg about 2.3. and in the real world they know folks are going to fluctuate between 2 +/- depending on how they drive, temperature and other factors.

and it makes the efficiency look good right? they know max range is about 314 miles so in thier testing im sure they noticed on avg the mi/kwh fluctuate between 2.1-2.5. so setting the baseline on this view to 2 makes it seems like its running efficient since its usually above the line.
 

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2 mi/kWh sounds reasonable for winter driving. I would expect consumption to be closer to 3 mi/kWh in warmer weather.
I'd guess more like 2.4 to 2.5. Very unlikely we will pull 400 miles of range.
 

ajdelange

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It's really unfortunate that Rivian chose to present consumption data in this way as it leads to confusion as is obviously the case here. The approach is a concession to drivers whom they feel will not be able to comprehend what wH/mi means because they are used to mpg as the metric which specifies a vehicle's energy consumption. But then we have ample history to suggest that Americans are too dumb to be able to understand the metric system putting us out of aligment with the rest of the world.

My grumbling aside, the 2.0 appears to be the label for a horizontal axis which I can barely see (or fancy I see) just below the dashed line. The Large trucks have, supposedly, a 135 kWh (available) battery and 314 mi rated range for a rated consumption of 135000/314 = 430 Wh/mi. The reciprocal of that is 2.33 mi/kWh which is evidently what we would like the dashed line to show so that a glance at the graph tells us instantly how we are doing relative to the only meaningful benchmark we have, the rated consumption.

The problem with this theory is that the average "efficiency" displayed is 2.29 mi/kWh which is clearly worse that the rated consumption even though the graph shows that the driver has been doing better than the reference throughout the whose 15 minutes bar one short period. This indicates that the reference line is not, as has been suggested here, 314/135 but the rated miles for some particular configuration other than the one that gives the often quoted EPA range of 314 miles (all terrain tires?).

To compute the average consumption over some time period or distance the computer has to find the area under the wH/mi curve. You can't do that with the m/kwh curve (you have to compute the harmonic average). The computer can compute the harmonic average but the driver cannot "eyeball" it from the curve (at least I can't) and the consumption vs distance/time curve loses much of its value to the driver (or at least to drivers who understand what's going on and who chose to while away the miles by keeping track of battery status). At the moment the biggest disappointment in the trucks is the failure of Rivian to provide a meaningful consumption vs distance graph with computed average consumption and average lines displayed upon it. What goes with this are trip odometers (plural) which display distance driven and energy consumed updated in real time. I've seen no mention of those. Has anyone else?
 

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I can always tell if an EV driver is trying to manage the power consumption on the freeway. As the road topology changes ups and downs, the EV slows down going up (by coasting/rolling up hill) and speeding up going down hill.

The last 15 miles is a typical indicator for the type of road you've been driving on. Clearly going up to the mountain is mostly uphill and will not represent return trip. There you would have to look at the entire travel history.

I haven't seen this mention other than just implied. That is, tire type (even if it is the same size but different attributes and make/model tire) makes a huge difference. Here's an example from my Model 3:

Original factory tire: Continental 235/40 19 96W ~ about 3.8 mi/kWh
New tire: Michelin Pilot Sport 4 same exact sizing ~ about 3.1 mi/kWh

Tire pressure at 42 psi for both. PS4 is, by far, the best street summer tires I've had on any vehicle. It is much more grippier and quite than Conti's; but, must has higher rolling resistance.

These are freeway numbers at average of 75~80 mph (average speed in SoCal, IF its moving...) so I would expect Rivian on 20" AT in the similar condition to be closer to 15~20% lower than the EPA baseline (21" all weather tires).

Pirelli claims that all of their Rivian tires are specially designed low resistance tires so it may be better than but data is not available to the public so who knows....
 

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my question is only “why 2 as a baseline”? I understand it won’t always meet the EPA range, but I thought it would be more valuable to see “efficiency vs manufacturer quoted estimate” than “efficiency vs arbitrary value”.

Oh but it's not arbitrary.

It's the nearest whole number to that vehicles actual efficiency.

That's how graphs work in virtually all applications. The axes are typically labeled with round numbers, just as in the Rivian efficiency graph.
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