Energy Graph on Speedometer

[dgpcolorado]

It varies with your speed. At slower speeds, around -15 kW is about where they come one. At higher speeds, it's around -30 to -35 kW.

I'd love it if there was a small tick mark on the regen meter that moved with speed to show the brake light threshold.

Why? My understanding is that the brake lights come on at a set deceleration rate (g force). If true, that doesn't have a direct link to kW of regen used at a given speed and I don't think the brake lights are controlled directly by level of regen. (I might be wrong about all that but that's what I recall reading about it.)

If the car is decelerating at a rate high enough to present a hazard to the following car, the brake lights come on. At a lower g force they don't — much like the gradual slowing of a conventional car due to engine compression when one backs off the gas. Isn't that enough? What difference does it make what the regen level and speed are?

Have you considered that those numbers would be completely different on hills versus the flatlands? I descend steep hills using heavy regen but travel at a constant speed. I don't think that the brake lights come on, nor should they.

 

[FlatSix911]

The units are confusing ...
if the energy average is shown as 400Wh/Mi in the display, then the circular power graph should show .4kW when cruising?

Sorry if this is a silly question, but what exactly does the energy graph on the right of the speedometer tell you?
Normally, the orange bar goes up a bit when accelerating (rarely above 75, though) and it turns green when regen braking.
Is this simply the amount of kw above or below your average (if so, which average)?
In other words, my average might be around 300kw, but this graph always hovers around 0kw and when accelerating might go up to usually less than 75kw.
Tried to search for this, but couldn't find anything. Maybe it's too self explanatory and I'm just missing it.
Screenshot below was taken from an image online - this is not my car.

The orange arc around the graph is instantaneous power draw (or regen) in kW.
The graph is energy use over a distance (the distance is determined by the Energy App on the 17inch screen) in Wh/Mile. Average energy over distance.

 

[Saghost]

The units are confusing ...
if the energy average is shown as 400Wh/Mi in the display, then the circular power graph should show .4kW when cruising?


View attachment 210559

If you're driving at 1 mph in a steady state, yes.

400 Watt-hours per mile. At 60 mph, that's 24 kW of instantaneous power.

 

[Boatguy]

The units are confusing ...
if the energy average is shown as 400Wh/Mi in the display, then the circular power graph should show .4kW when cruising?
View attachment 210559

There are two different pieces of information being displayed.

The circular graph is displaying instantaneous power flowing to/from the battery with no time or distance component.

The text is showing the average power consumed during the time period selected in the CID Energy app, per mile.

I haven't tried it, but I think if you selected "Instantaneous" in the Energy app (rather than 5/15/30 minutes), then as @Saghost noted, if it showed 400Wh/mi and you were traveling at 60mph, then the circular graph should indicate 24kW.

Two different pieces of information with different units.

 

[FlatSix911]

If you're driving at 1 mph in a steady state, yes.
400 Watt-hours per mile. At 60 mph, that's 24 kW of instantaneous power.

There are two different pieces of information being displayed.
The circular graph is displaying instantaneous power flowing to/from the battery with no time or distance component.
The text is showing the average power consumed during the time period selected in the CID Energy app, per mile.

I haven't tried it, but I think if you selected "Instantaneous" in the Energy app (rather than 5/15/30 minutes),
then as @Saghost noted, if it showed 400Wh/mi and you were traveling at 60mph, then the circular graph should indicate 24kW.
Two different pieces of information with different units.

I see what you are saying, but the units still do not work ... Wh/mi x mi/hr?

 

[Saghost]

I see what you are saying, but the units still do not work ... Wh/mi x mi/hr?

What is it you're having trouble with here?

If you take watt hours per mile and multiply by miles per hour, miles and hours both show up in both the numerator and the denominator, so they cancel out, leaving you with watts.

 

[krazineurons]

If you're driving at 1 mph in a steady state, yes.

400 Watt-hours per mile. At 60 mph, that's 24 kW of instantaneous power.

this is so helpful, now suddenly the <75kW value on the ARC looks frightening! My takeaway is be as gentle on the paddle and ensure the arc doesn't see huge numbers this is similar to driving the ICE and making sure the MPG meter is in the happy range.

 

[Saghost]

this is so helpful, now suddenly the <75kW value on the ARC looks frightening! My takeaway is be as gentle on the paddle and ensure the arc doesn't see huge numbers this is similar to driving the ICE and making sure the MPG meter is in the happy range.

It's all about the average over distance. Accelerating to given speed requires a certain amount of kinetic energy.

There may be a small advantage to accelerating slower, but if you're averaging the same speed for the whole trip, the efficiency will come out pretty similar.

In addition to keeping the speed down, the other thing you want to avoid is hitting the brake pedal. Not having to use regen is better than using regen, but hitting the friction brakes is much worse (though not as bad as hitting something, of course. )

 

[Az_Rael]

The units are confusing ...

THIS. They are mixing a graph that displays Watt-hours/mile with a power meter that displays kW all in one display.

I never really knew why Tesla went with the Wh/mile version instead of the inverse miles/kWh which seems like it might be more intuitive and easier to understand on the fly. I.e if I am driving super aggressively (or its cold) and I am only getting 2.2 miles/kWh on average then I might have a better idea of how far short I might come up on the range vs seeing 450wh/mile, which doesn't really mean anything to me except that its high.

It would be awesome to have the option to customize that graph to show either wh/mile or mile/kWh.

 

[FlatSix911]

What is it you're having trouble with here? If you take watt hours per mile and multiply by miles per hour, miles and hours both show up in both the numerator and the denominator, so they cancel out, leaving you with watts.

Correct on the units ... but they are still mixing Energy and Power on a single display
More info here: kW and kWh Explained - Understand & Convert Between Power and Energy

What is the difference between a kW and a kWh?
kWh is a measure of energy, whilst kW is a measure of power...
What is energy?
Energy is a measure of how much fuel is contained within something, or used by something over a period of time. The kWh is a unit of energy.
What is power?
Power is the rate at which energy is generated or used. The kW is a unit of power.

this is so helpful, now suddenly the <75kW value on the ARC looks frightening! My takeaway is be as gentle on the paddle and ensure the arc doesn't see huge numbers this is similar to driving the ICE and making sure the MPG meter is in the happy range.

Agreed ... It's a measure of instantaneous power for a short duration

THIS. They are mixing a graph that displays Watt-hours/mile with a power meter that displays kW all in one display.

I never really knew why Tesla went with the Wh/mile version instead of the inverse miles/kWh which seems like it might be more intuitive and easier to understand on the fly. I.e if I am driving super aggressively (or its cold) and I am only getting 2.2 miles/kWh on average then I might have a better idea of how far short I might come up on the range vs seeing 450wh/mile, which doesn't really mean anything to me except that its high. It would be awesome to have the option to customize that graph to show either wh/mile or mile/kWh.

Agree again ... the mixed units in the IC display can cause confusion as one is Energy and the other is Power

 

[Saghost]

Correct ... thanks, but they are mixing Energy and Power on a single display
kW and kWh Explained - Understand & Convert Between Power and Energy

No. One is instantaneous power, the other is efficiency - energy *divided by distance*.

Yes, it is two different units in one display area, but that's hardly unprecedented - trip computers routinely show several different types of units at the same time, just like Tesla's does - and these have more relation to each other than those do.

It's conceptually no different than having the odometer in the middle of the speedometer.

 

[xsi123]

I never really knew why Tesla went with the Wh/mile version instead of the inverse miles/kWh which seems like it might be more intuitive and easier to understand on the fly. I.e if I am driving super aggressively (or its cold) and I am only getting 2.2 miles/kWh on average then I might have a better idea of how far short I might come up on the range vs seeing 450wh/mile, which doesn't really mean anything to me except that its high.

It would be awesome to have the option to customize that graph to show either wh/mile or mile/kWh.

Totally agree. miles/KWh whould be much better option. And it would make a lot of sense. We all used to count almost anything in miles/xyz (miles/gallon, miles/hour etc..). Maybe Tesla wants us to change our thinking and start count everything in KWh...

 

[mblakele]

Totally agree. miles/KWh whould be much better option. And it would make a lot of sense. We all used to count almost anything in miles/xyz (miles/gallon, miles/hour etc..). Maybe Tesla wants us to change our thinking and start count everything in KWh...

We might have to start with mpg, but what we really want to know is dollars per trip. You can think about your Tesla in (equivalent) mpg if you like. It's rated 90-100 (e)mpg. But if you want to know how much a trip will cost, it's better to measure gallons per 100 miles (g/100mi) for an ICE, or Wh/mi for an EV. Plug in dollars per gallon and miles for the trip, and you have cost per trip. This is what most other countries use.

 

[FlatSix911]

We might have to start with mpg, but what we really want to know is dollars per trip. You can think about your Tesla in (equivalent) mpg if you like. It's rated 90-100 (e)mpg. But if you want to know how much a trip will cost, it's better to measure gallons per 100 miles (g/100mi) for an ICE, or Wh/mi for an EV. Plug in dollars per gallon and miles for the trip, and you have cost per trip. This is what most other countries use.

Agreed ... here is some additional information on MPGe ... Miles per gallon gasoline equivalent - Wikipedia

As part of the research and redesign process, EPA conducted focus groups where participants were presented with several options to express the consumption of electricity for plug-in electric vehicles. The research showed that participants did not understand the concept of a kilowatt hour as a measure of electric energy use despite the use of this unit in their monthly electric bills. Instead, participants favored a miles per gallon equivalent, MPGe, as the metric to compare with the familiar miles per gallon used for gasoline vehicles. The research also concluded that the kW-hrs per 100 miles metric was more confusing to focus group participants compared to a miles per kW-hr. Based on these results, EPA decided to use the following fuel economy and fuel consumption metrics on the redesigned labels: MPG (city and highway, and combined); MPGe (city and highway, and combined); Gallons per 100 miles; kW-hrs per 100 miles.

 

[steveho]

I disagree that we should look at miles / kw, or the equivalent old school miles / gallon. I believe that we should switch all ICE cars to gallons / mile or per 10,000 miles. So an ICE car would burn 500 gallons per 10,000 miles, which would be the equivalent of 20 miles per gallon. BECAUSE if people knew they were burning 500 gallons per 10,000 miles, they may stop and think about how much they are actually consuming, instead of some theoretical number of 20 miles per gallon. With 20 MPG, you don't know how much you are consuming.

 

[Boatguy]

Totally agree. miles/KWh whould be much better option. And it would make a lot of sense. We all used to count almost anything in miles/xyz (miles/gallon, miles/hour etc..). Maybe Tesla wants us to change our thinking and start count everything in KWh...

FWIW, my BMW i3 EV quotes in mi/kWh. I just flip my thinking around when switching cars. Small number is good in the Tesla, big number is good in the BMW.

 

[tarponman]

I believe the dotted white Avg Wh/mi mile line moves up and down (please correct me if I am wrong). Is Tesla trying to tell us if that if you drive at where the line would hit the kW arc you would continue to get your average wh/mi?

 

[Saghost]

I believe the dotted white Avg Wh/mi mile line moves up and down (please correct me if I am wrong). Is Tesla trying to tell us if that if you drive at where the line would hit the kW arc you would continue to get your average wh/mi?

Interesting thought. I don't think it can work that way - neither element is adjusted with speed alone, and to get a consistent relationship between the two I think you need a constant speed.

 

[Boatguy]

I believe the dotted white Avg Wh/mi mile line moves up and down (please correct me if I am wrong). Is Tesla trying to tell us if that if you drive at where the line would hit the kW arc you would continue to get your average wh/mi?

You're talking about the instrument display energy app? Yes, the dotted line moves up and down to reflect the average Wh/mi for the period selected in the CID Energy app (5/15/30mi), and displayed in small type across the bottom of the Instrument Display energy app. So, yes, if you kept the instantaneous line on the dotted line you would continue to consume at the same rate as you had for the averaging period.

Probably more useful is knowing that if the instantaneous line is above your average, your average will slowly rise, and if below, your average will slowly fall.

 

[Liion-nat]

In the re-gen portion of the energy arc (about the last 30 degrees of the arc and displayed on the dashboard panel) occasionally a yellow dashed arc segment appears. What does this mean? Sometimes, along with the yellow dashed arc segment a yellow caution triangle (with an exclamation mark) appears. What does this mean?