Effect of wind speed/direction on consumption

[Deep purple]

Just been to LHR and back from Jct 18 of M4 with a strong SW wind. It's blindingly obvious physics but the impact of wind speed on M/KWhr is much more noticeable in an EV when one is concentrating on the GOM and wondering what margin will be left when getting back home!
It was 4.5 on way there and 3.6 on the way back. I was hoping to find a fast, large artic on the way home so I could tuck in with adaptive cruise control but failed.
The last time I worried about wind speed and direction when planning a route was sailing cross channel! But at least in an EV tacking isn't required.

 

[Gomev]

When sailing across the channel I generally leave the details to the ferry captain.

 

[Alb]

But at least in an EV tacking isn't required.

You haven't encountered Lane Keep Assist

 

[fshuk1]

This is true and seems to have consequences.

I went to wales. Going there nice weather, no charging required. Found the Tesla chargers open to us and tested them. excellent. consumption was around 4m/kwh (don't remember for sure because it was not an issue but certainly over 4)
On the way back went to Tesla charger, charged to about 80% (was all I needed to make it back home) and set off. Suddenly the weather changed. Torrential rain all the way. I then noticed 3.3 m/kwh !!! At this consumption I couldn't make it home. So we stopped at the Porsche showroom in Swindon for an extra 12kwh of charging which got us home. (Bonus story for you NEVER go to that Porsche charging. They charged per kwh AND per minute)
So now for the consequence. Driving in rain etc doing 60mph trying to overtake and there was hardly any

Just been to LHR and back from Jct 18 of M4 with a strong SW wind. It's blindingly obvious physics but the impact of wind speed on M/KWhr is much more noticeable in an EV when one is concentrating on the GOM and wondering what margin will be left when getting back home!
It was 4.5 on way there and 3.6 on the way back. I was hoping to find a fast, large artic on the way home so I could tuck in with adaptive cruise control but failed.
The last time I worried about wind speed and direction when planning a route was sailing cross channel! But at least in an EV tacking isn't required.

acceleration from the car. Others have noticed this. There seems to be something stopping the power. I have not noticed this before, so I am thinking it is to do with the 3.3 m/kwh). May be if the consumption is high the car software stops high speeds. Back home and my cars consumption and acceleration is exactly same as it was before.

 

[kevin ellard]

They charged per kwh AND per minute)

I saw quite a few charge points in France that were advertised like that. It seemed quite a good idea as it encourages people to move on as soon as they can. (Or course, the fact that it was quite a lot cheaper overall that in the UK may have clouded my judgement)

 

[fshuk1]

I saw quite a few charge points in France that were advertised like that. It seemed quite a good idea as it encourages people to move on as soon as they can. (Or course, the fact that it was quite a lot cheaper overall that in the UK may have clouded my judgement)

it worked out to 90p per kwh !!!!!!!

 

[Tonych]

Just been to LHR and back from Jct 18 of M4 with a strong SW wind. It's blindingly obvious physics but the impact of wind speed on M/KWhr is much more noticeable in an EV when one is concentrating on the GOM and wondering what margin will be left when getting back home!
It was 4.5 on way there and 3.6 on the way back. I was hoping to find a fast, large artic on the way home so I could tuck in with adaptive cruise control but failed.
The last time I worried about wind speed and direction when planning a route was sailing cross channel! But at least in an EV tacking isn't required.

My wife was driving on a motorway trip last year and hung behind a big truck and managed to get upper 4 miles per kw consumption. Makes a difference!

 

[Gomev]

I saw quite a few charge points in France that were advertised like that. It seemed quite a good idea as it encourages people to move on as soon as they can. (Or course, the fact that it was quite a lot cheaper overall that in the UK may have clouded my judgement)

Which is great if your car charges really fast, but not so good if your car can't take as much power.

 

[Petriix]

Found the Tesla chargers open to us

Which site did you visit?

 

[kevin ellard]

Which is great if your car charges really fast, but not so good if your car can't take as much power.

I think that is the point. If you are taking up the charger for a longer then you should pay more for the "rent" of the space.

 

[Tonych]

Which site did you visit?

Possibly Tesla at Flint Mountain - I have been there with my MG

 

[Gomev]

I think that is the point. If you are taking up the charger for a longer then you should pay more for the "rent" of the space.

But the other point is that it penalises us with slower (cheaper) charging cars and we pay more than the owner of a Porsche Taycan for filling up the same amount.
Outrage at the petrol forecourt if Porsche owners paid less for their fuel than those with an old Fiesta.

 

[kevin ellard]

But the other point is that it penalises us with slower (cheaper) charging cars and we pay more than the owner of a Porsche Taycan for filling up the same amount.
Outrage at the petrol forecourt if Porsche owners paid less for their fuel than those with an old Fiesta.

There would also be outrage on the forecourt I it took me 3 hours to fill up my car with petrol. Those of us with slower charging cars (I count my MG5 as one of those) should probably pay just a little more for the amount of time we take up the space at a charging point.

 

[fshuk1]

Which site did you visit?

The Celtic Manor Resort

 

[Rookery]

I agree about the wind affecting consumption, driving back from Scotland I had a constant strong westerly wind buffeting the car side on and it certainly reduced my miles per kW.

 

[Esi]

Just been to LHR and back from Jct 18 of M4 with a strong SW wind. It's blindingly obvious physics but the impact of wind speed on M/KWhr is much more noticeable in an EV when one is concentrating on the GOM and wondering what margin will be left when getting back home!
It was 4.5 on way there and 3.6 on the way back. I was hoping to find a fast, large artic on the way home so I could tuck in with adaptive cruise control but failed.
The last time I worried about wind speed and direction when planning a route was sailing cross channel! But at least in an EV tacking isn't required.

Hi
You have averaged 4.0 that’s because the wind that was pushing you back was also the same pushing you on your way back.

 

[Tangoed Man]

This is true and seems to have consequences.

I went to wales. Going there nice weather, no charging required. Found the Tesla chargers open to us and tested them. excellent. consumption was around 4m/kwh (don't remember for sure because it was not an issue but certainly over 4)
On the way back went to Tesla charger, charged to about 80% (was all I needed to make it back home) and set off. Suddenly the weather changed. Torrential rain all the way. I then noticed 3.3 m/kwh !!! At this consumption I couldn't make it home. So we stopped at the Porsche showroom in Swindon for an extra 12kwh of charging which got us home. (Bonus story for you NEVER go to that Porsche charging. They charged per kwh AND per minute)
So now for the consequence. Driving in rain etc doing 60mph trying to overtake and there was hardly any


acceleration from the car. Others have noticed this. There seems to be something stopping the power. I have not noticed this before, so I am thinking it is to do with the 3.3 m/kwh). May be if the consumption is high the car software stops high speeds. Back home and my cars consumption and acceleration is exactly same as it was before.

Rain will knock out any decent mpg regardless of propulsion simply because you are constantly pushing against water; my E-class Mercedes regularly does 62mpg but that will drop to 50mpg in the rain. Ditto wind direction.

 

[turntoport]

quite probably the ambient air temperature dropped quite a bit in the rainy time, perhaps to the point where more battery heating was required. The liquid water in the airflow also removes heat much more effectively from the car, greatly exacerbating the effect if indeed it is contributing.

 

[Deep purple]

Esi, although the average is 4 (which is about 5% worse than I normally can achieve) it doesn't quite work out that you get back what you lose on this sort of trip because the consumption/speed curve is not a straight line as drag (which is the main way the energy is used) goes up with the square of speed. Obviously there are all the base loads which are not speed dependant (lights/fan/steering/radio/etc) and these can be quite large if aircon or heating are used.
So on the way there at a steady 60 with a 15 mph tailwind the car was effectively seeing drag equivalent to doing about 45 whilst on the way back it experienced 75. The increase of 67% in apparent speed will cause an increase of 177% in drag,
What I could have done is to drive faster than 60 mph on the way there and slower on the way back! Or found a lorry to shield me from the headwind.
But life is too short to worry too much, it's just an interesting side effect of spending the whole journey with range anxiety.

 

[fshuk1]

Esi, although the average is 4 (which is about 5% worse than I normally can achieve) it doesn't quite work out that you get back what you lose on this sort of trip because the consumption/speed curve is not a straight line as drag (which is the main way the energy is used) goes up with the square of speed. Obviously there are all the base loads which are not speed dependant (lights/fan/steering/radio/etc) and these can be quite large if aircon or heating are used.
So on the way there at a steady 60 with a 15 mph tailwind the car was effectively seeing drag equivalent to doing about 45 whilst on the way back it experienced 75. The increase of 67% in apparent speed will cause an increase of 177% in drag,
What I could have done is to drive faster than 60 mph on the way there and slower on the way back! Or found a lorry to shield me from the headwind.
But life is too short to worry too much, it's just an interesting side effect of spending the whole journey with range anxiety.

There should be no range anxiety, really. Whenever you want to see if you can make it, see what % battery you have left. Calculate how much range that gives you but use a lower miles/kwh than you usually get. So I usually get over 4 m/kwh but I always use 3.7 in my calculations. Waze or google map tells you how many miles you have to your destination. If you have say 20 miles extra you will make it. No anxiety. If you notice less than 3.7 then do you calculations again with what m/kwh you actually see. Again if you can make with with 20 miles ish extra relax.