Gauge Unit Question - kW vs W

[Remonster]

I was given a P85D as a loaner while my Model 3 was in service. Why does the instantaneous gauge read with units in kW with values -50 through 400? Isn't that very clearly watts?

It says Avg usage in watts*hrs/mile right in the center.

I certainly may be missing something obvious haha.

 

[Hugh Mannity]

It’s showing you the calculation of instantaneous and average consumption. The 3 doesn’t do this?

It’s easier to display the numbers in kW vs just Watts since the numbers are so large. Unless you want it to say 400000 W drain when you mash the pedal. I guess that would look cooler. Hah

Ooo I have an idea. I’m going to tell people my car sends 400 billion picoWatts to the motors when you accelerate. Ooooooo, ahhhhhhh

 

[Remonster]

The Model 3 only shows average power consumption over a trip meter. We do not get instantaneous as a display.

It’s showing you the calculation of instantaneous and average consumption. The 3 doesn’t do this?

I guess in that case I'm just surprised that instantaneous usage could be as high as 400 kW. That seems improbable, but I didn't watch the gauge hard enough get an idea of my average.

 

[David99]

It's kW. The Model S draws well over 400 kW from the battery at full acceleration. The regeneration power is a little over 70 kW under best conditions.

W or kW is power.
Wh or kWh is energy.

Those are not the same.

Driving with aprox 20 kW (= 20,000 Watt) power at a speed of 67 mph results in an energy usage of 300 Wh/mile.

 

[luckyj]

I guess in that case I'm just surprised that instantaneous usage could be as high as 400 kW. That seems improbable, but I didn't watch the gauge hard enough get an idea of my average.

400kW = ~536HP, so that should not be unexpected. 400 watts is like 1/2 HP....that can't make a car go 0-60 in ~4s

 

[Remonster]

It's kW. The Model S draws well over 400 kW from the battery at full acceleration.

That's a lot more than I suspected.

 

[Rockster]

In the peak of the summer, when both of my home’s air conditioners are running, along with the normal lights and appliances, my house draws about 10 kW. It boggles my mind that my car can draw 40x that from its battery.

 

[MarcusMaximus]

On this note, it would be nice if average usage could be displayed in miles/kWh... it’d be a more straightforward conversion to see how my usage compares to the EPA rated miles.

 

[Feathermerchan]

In the peak of the summer, when both of my home’s air conditioners are running, along with the normal lights and appliances, my house draws about 10 kW. It boggles my mind that my car can draw 40x that from its battery.

That is one reason a car pollutes more than your house. It draws that much energy from a gasoline engine too when equipped.

 

[Mediocrates]

In the peak of the summer, when both of my home’s air conditioners are running, along with the normal lights and appliances, my house draws about 10 kW. It boggles my mind that my car can draw 40x that from its battery.

Your house isn't moving.

 

[whitex]

I’m going to tell people my car sends 400 billion picoWatts to the motors when you accelerate. Ooooooo, ahhhhhhh

400 billion picoWatts = 400mW = 0.4W
You must drive a HotWheels Tesla. What's your 0-60?

 

[TJtv]

On this note, it would be nice if average usage could be displayed in miles/kWh... it’d be a more straightforward conversion to see how my usage compares to the EPA rated miles.

No, that would be a terrible idea. We've been expressing fuel economy incorrectly as MPG for way too many years now when we should have been using GPM. We finally have a chance to change things for the better and use the proper numerator/denominator now that EVs are becoming more commonplace. Let's not screw up our chance.

 

[whitex]

No, that would be a terrible idea. We've been expressing fuel economy incorrectly as MPG for way too many years now when we should have been using GPM. We finally have a chance to change things for the better and use the proper numerator/denominator now that EVs are becoming more commonplace. Let's not screw up our chance.

US uses mileage (MPG), Canada (and other countries) uses L/100km (fuel consumption). Wh/mile (or Wh/km) is EV fuel consumption equivalent and it's a good measure because it provides a good scale/range without going into fractions or numbers into thousands. You could however also make a meaningful mileage for EV's as well, say miles/10KWh.

 

[David99]

the car could easily show the data in different formats. There are arguments for both ways. Miles per kWh can be useful. Just as much as kWh per 100 km. Both are not very helpful to new EV owners as your car doesn’t show you how much energy you have left is kWh. So either way to show energy usage doesn’t help much.

 

[David29]

On this note, it would be nice if average usage could be displayed in miles/kWh... it’d be a more straightforward conversion to see how my usage compares to the EPA rated miles.

I have thought that way from time to time, as well. Some other EVs use that approach, and it makes more sense to a non-EV driver. Easier to explain to someone what your cost per mile is -- 3 miles per kWh corresponds to 7 cents per mile if electricity costs 21 cents/mile -- easier to compare to cost per mile for gasoline. Most folks can do that math in their head, or close enough.

But one problem is that the variation is in the 2nd or 3rd decimal place, so it can get awkward. My car's EPA rating corresponds to 292 Wh/mi, which is 3.42 mi/kWh. If I get 325 Wh/mi on a given trip, that is 3.08 mi/kWh. Seems awkward to compare 3.42 to 3.08 in spoken conversation, especially. So it might work better to turn it into miles per 100 kWh -- 342 or 308 might be easier to compare, with no decimals. But the "per 100 kWh" is also awkward.

Still, maybe Tesla could provide the option for miles/kWh, just as they provide for miles or % for battery SOC.