Wind effect on Tesla’s power consumption

[Exscite]

Wind effect on Tesla’s power consumption

Tesla drivers make sure not to overlook the wind effect on your driving range.
Driving from Arizona to California (on I-40) on a very windy day, we stopped at a Needles CA, a very unpleasant and noisy Supercharger location inside a gas station. My Tesla M3 estimated that I have a good number of miles safety distance to Barstow CA, so I didn’t charge to full capacity (how stupid of me).

The freeway is fast, and driving speed is 70-75 m/h and the head wind was very scary indeed. About half way we noticed a message in yellow on our Tesla screen: “Drive below 70 to reach your destination” and sometime later “drive below 60”. It dawned on us that this is a warning to slow down to conserve charge, and it can lead to a serious situation driving in the desert. My driver (my wife) eased up and slowed down to cruising speed of 60, while I was looking for a shorter alternative. We took a slight detour and ended up in a new (and great) Supercharger in Yarmo CA (on I-15), which saved us about 15 miles, and still we have arrived there with only 25 miles to spare.

The moral of the story:
Wind (head or cross) is a major factor in the electrical charge consumption. Always take it into account and make sure to have enough spare miles on a windy day, beyond the recommended distance.

PS.

I have found a five year old post here,about wind effect on Tesla’s power consumption that may be of interest for the physics geeks among us: Crosswinds have big impact on range/Does this sound right?

 

[Zoomit]

Welcome to the world of highly efficient vehicles. Teslawinds.com is a browser favorite in my car.

Tesla Winds and Elevation Web Browser App

 

[TiggerTime]

Everyone does realize that it is not just EV that are affected by wind forces right? all Planes, train and automobile as well as boats are too. Why does everyone seem so surprised and caught of guard? I understand there are not charge locations on every corner yet but still ...

 

[OCR1]

Everyone does realize that it is not just EV that are affected by wind forces right? all Planes, train and automobile as well as boats are too. Why does everyone seem so surprised and caught of guard? I understand there are not charge locations on every corner yet but still ...

You answered your own question...because we don't have charging stations on every corner yet. And you can't have AAA show up with a spare container of gasoline to get you to the next station.

 

[SageBrush]

The moral of the story:
Wind (head or cross) is a major factor in the electrical charge consumption.

cross-wind less so, but a head wind of x mph is the same as driving x mph faster on a windless day.
And faster driving increases aero resistance quadratically.

 

[RDoc]

We've been caught a couple of time on long distance drives with strong head winds accompanied by sleet and rain. That was really terrifying for range.

The reason people don't notice it in ICE vehicles is because the range is generally much greater and refueling is trivial.

 

[Zoomit]

cross-wind less so, but a head wind of x mph is the same as driving x mph faster on a windless day.
And faster driving increases aero resistance quadratically.

To be a little more precise, the headwind only increases the aero drag and at highway speeds that drag is responsible for 50-80% of the energy consumption. So for example a straight-on headwind of 10 mph is equal to about a 5-8 mph speed increase.

But winds are rarely just straight-on and Cd increases with a crosswind. Some car designs are more sensitive to crosswind-induced Cd rise than others. Using the previous example, since the vehicle's Cd goes up with a likely crosswind and the vehicle is experiencing more wind overall, the 5-8 mph speed increase goes back up to near a 10 mph equivalent speed increase on a windless day.

None of this is linear though. It depends on wind speed relative to vehicle speed plus wind angle relative to vehicle heading plus vehicle Cd as a function of crosswind component.

 

[animorph]

That's why you watch the charge remaining at destination on the nav turns list while you're driving. You would have seen it slowly (or rapidly) decreasing well before the car warned you to slow down. Then you can start slowing down earlier by a few MPH instead of having to go 60 MPH for the last portion of the trip. Our worst case was a sudden rain storm just as we left a Supercharger.

The nav will take past conditions into consideration when estimating the charge remaining at destination. But a headwind or rain that starts after you leave the Supercharger is beyond its current capabilities.

We are kind of driving from oasis to oasis in a desert. It pays to keep an eye on your charge status.

 

[SageBrush]

That's why you watch the charge remaining at destination on the nav turns list while you're driving.

The other way is to check the trip graph. So long as the actual consumption stays above the calculated line all is good.

 

[Silicon Desert]

This thread reminds me of something. A couple of years ago when going across I80 in Kansas, the wind was so strong I thought it would blow me over (well not really). And I got the "slow it down message". Then I thought, OK so this is why Dorothy got blown all the way to the land of OZ.

A strong headwind does sometimes get my attention. Yet, on most of my cross country trip, I found it just balances out over a long period of time since the wind (not air resistance) comes from all direction. And a couple of times I was surprised along that same route to get an extra 40 miles out of a charge due to a strong tail wind.

 

[ngogas]

Yup wind and weather can always impact travel plans.

 

[ChadS]

The only time I ever ran out of gas in an ICE was when I hit headwinds in South Dakota 30 years ago. The headwinds mean my mpg went way down, which means I ran out of gas far earlier than expected, so I shouldn't have ignored that "last gas for X miles" sign.

Of course, another way of looking at it (the way my wife likes to look at it) is that I ran out of gas because I ignored the "last gas" sign. I calculated that we had enough, but my calculations didn't allow for extreme circumstances. You really shouldn't plan to run your gas car all the way to empty. She's right, really, it was my fault. Some seem to make a sport out of running their EVs down to empty...but not me. The bottom of the tank - whether it's gas or electrons - is where all the drama is. Stay away from it and your life will be easier.

 

[JulienW]

I only drive downhill with a tail wind. So I have to always add range. What a PIA.

 

[Rojer Lockless]

Wind effect on Tesla’s power consumption

About half way we noticed a message in yellow on our Tesla screen: “Drive below 70 to reach your destination” and sometime later “drive below 60”. It dawned on us that this is a warning to slow down to conserve charge.

View attachment 409537

Golly gee willkers, You'd think it was trying to tell you something! I'm happy you two could decrypt the message that literally says what to do and why!

 

[Silicon Desert]

The only time I ever ran out of gas in an ICE was when I hit headwinds in South Dakota 30 years ago. The headwinds mean my mpg went way down, which means I ran out of gas far earlier than expected ....

And unfortunately ICE cars never tell us that we aren't going to make it to our next stop. At least the Tesla tells us what we have to do to make it there.