Speed vs Battery Consumption

[Mark55]

Hi
I am soon to be the owner of an ID.3 Max Pro.
One thing I have been wondering about is how speed affects electric consumption.
Most of my driving will be on local A roads of no more that 50 miles round trips.
But every now and then a 210 mile round trip will need to be done.
If needing to maximise range, would it be a benefit to drive slower. Say driving at 50mph or 60mph instead of 70mph?
Is the a speed at which the electric consumption increases a lot?
Thanks

[Deleted User 192]

I'd rather drive at 70mph and make a quick "splash and dash" charge stop if needed.

I would also feel more comfortable doing that than being surrounded by 44-ton lorries on the motorway.

Air resistance is your biggest enemy, but I'm no physicist so couldn't begin to tell you how much - the slower the "better" in terms of efficiency.

[Deleted User 314]

Apart from the first 3 weeks of ownership I've driven normally. I feel very unsafe on motorways driving at 50/60, especially here.

You very quickly get to learn your car/drives so the "splash and dash" approach is exactly how we drive too.

[Mark55]

The 210 mile round trip is normal at night and in late November then late February so temperature will be low. Basically an airport run. Drive down in the middle of the night to catch very early flight. Then week later, fly back late, leaving the airport around 11pm.
That a point how much battery will the car use when parked up for a week?

[TheJimster]

I think there's another thread here where someone has demonstrated (with actual maths!) that electricity use at 70mph is dramatically higher than at say 50mph.

But I agree with what others here have said, driving at 70 and scheduling a quick rapid charge does seem like the way to go.

[DSB18]

I have just parked my car up for 10 days at Manchester airport and when I got out it said 162 mile range, when I got back in and started driving it quickly went down to 156 range, so it didn't loose very much range sitting for 10 days.

[colonelpurple]

Hi
I am soon to be the owner of an ID.3 Max Pro.
But every now and then a 210 mile round trip will need to be done.
If needing to maximise range, would it be a benefit to drive slower. Say driving at 50mph or 60mph instead of 70mph?
Thanks

In summer (as I have never had the car in winter)
To maximise range drive at 50 (get 3.8 and above). No hard acceleration. Keep AC on mildly chill
To minimise journey time drive at 70 or more (get 3.5 and above)

thats basically it

I drive to enjoy, not to economise, except for long journeys

For a 58km ID3, 210 miles is ok if you fill up to 100% and try not to drive over 50 too much. You would get back with 5-15%, depending on the average road speed and the type of roads on the way
If you drive 70-80 you might be pushing this range
Also heavy acceleration uses electricity. Try to be light on the peddle

My rule of thumb, as I am risk averse and didn't like my ICE going under half a tank, is that if I am doing over 150 miles in a day on a there and back run, I like to plan a fill up at a mid or near mid stopping point, but I never charge more then 90% and hate my car going under 20%

If I am going on a long one way journey, I would arrange a top up at least before every 160miles, but that's just me. I went from london to chester, which was 207 miles. I topped up at Moto services m6 junction 1. The 50w fast charger was 15-20 mins, enough time for toilet and a coffee

To give some practical examples, I did north london to mersea (near colchester) 155 round trip, I went from 90% to 21% - this journey was mostly under 50
Yesterday, I went from north london to Stowe, bicester and then back, 133 miles in total, this was 90% to 20% - this journey was mostly 70 and over

So the way you drive and the road speed make a big difference

[Deleted User 192]

I have just parked my car up for 10 days at Manchester airport and when I got out it said 162 mile range, when I got back in and started driving it quickly went down to 156 range, so it didn't loose very much range sitting for 10 days.

And that "loss" of 6 miles might just be cos it's colder now - did the % change?

[Deleted User 192]

The 210 mile round trip is normal at night and in late November then late February so temperature will be low. Basically an airport run. Drive down in the middle of the night to catch very early flight. Then week later, fly back late, leaving the airport around 11pm.
That a point how much battery will the car use when parked up for a week?

I would do a "splash and dash" just before dropping it at the airport, back up to 80% (the batteries don't like being kept at levels close to 100% for a length of time)

Then you know you'll easily get home when you return.

[Bromsgroveuser]

Hi
I am soon to be the owner of an ID.3 Max Pro.
But every now and then a 210 mile round trip will need to be done.
If needing to maximise range, would it be a benefit to drive slower. Say driving at 50mph or 60mph instead of 70mph?
Thanks

In summer (as I have never had the car in winter)
To maximise range drive at 50 (get 3.8 and above). No hard acceleration. Keep AC on mildly chill
To minimise journey time drive at 70 or more (get 3.5 and above)

thats basically it

I drive to enjoy, not to economise, except for long journeys

For a 58km ID3, 210 miles is ok if you fill up to 100% and try not to drive over 50 too much. You would get back with 5-15%, depending on the average road speed and the type of roads on the way
If you drive 70-80 you might be pushing this range
Also heavy acceleration uses electricity. Try to be light on the peddle

My rule of thumb, as I am risk averse and didn't like my ICE going under half a tank, is that if I am doing over 150 miles in a day on a there and back run, I like to plan a fill up at a mid or near mid stopping point, but I never charge more then 90% and hate my car going under 20%

If I am going on a long one way journey, I would arrange a top up at least before every 160miles, but that's just me. I went from london to chester, which was 207 miles. I topped up at Moto services m6 junction 1. The 50w fast charger was 15-20 mins, enough time for toilet and a coffee

To give some practical examples, I did north london to mersea (near colchester) 155 round trip, I went from 90% to 71% - this journey was mostly under 50
Yesterday, I went from north london to Stowe, bicester and then back, 133 miles in total, this was 90% to 70% - this journey was mostly 70 and over

So the way you drive and the road speed make a big difference

Am i reading this right you did 133 miles and only dropped 20% that's over 600 miles on a full battery ?

[colonelpurple]

Am i reading this right you did 133 miles and only dropped 20% that's over 600 miles on a full battery ?

whoops! Freudian slip

I meant 21% and 20% - have corrected above

[StuartT]

Hi
I am soon to be the owner of an ID.3 Max Pro.
One thing I have been wondering about is how speed affects electric consumption.
Most of my driving will be on local A roads of no more that 50 miles round trips.
But every now and then a 210 mile round trip will need to be done.
If needing to maximise range, would it be a benefit to drive slower. Say driving at 50mph or 60mph instead of 70mph?
Is the a speed at which the electric consumption increases a lot?
Thanks

In support of those who don't mind doing 60mph on a motorway, and this place has had some schisms lately(! ), I did a 220 mile round trip yesterday and got home with 15% charge left. I'd call myself a steady driver (driving too fast with hand-controls can get too lively, for my liking...) and, even though I've only had the car for just over a month, I've already learnt that the car is very sensitive to changes in power demands. You'll find out how your driving works with the car and what consumption figures you'll get - it seems to be a very individual thing. I'm just saying what I get, in order to try and show how much it varies and how sensitive it is to so many different factors. If, ifs and ands were pots and pans I'd have a sink full, as my mum used to say.

[sausageroll]

Is the a speed at which the electric consumption increases a lot?

Regardless of technology (ICE or EV) the amount of power required to propel a vehicle remains constant. It is basically a factor of gravity (mass) and drag.

Assuming the vehicle is a constant, the amount of drag gets somewhat exponential with speed, such that the faster you go, the more drag will be produced - but it's not linear - e.g. the drag at 50mph is not double that of 25mph. Basically put, if you want to drive twice as fast, you need eight times the power.
With that in mind, you also have to add in that doing 70mph up a 20% gradient requires more power (effort) than on a perfectly flat road.
Then, the additional factors are involved in the wind speed.

Add in then the factors of having a roof box, a window open, tyre pressures and compounds, weight in the car, and other rolling-resistance stuff. That will all add to the exponential stuff.

You have to also consider the fact that an EV has all of its power available instantly - there's no factor of a sweet spot in the RPM where engine power builds up to and peaks.
As the ID.3 (and many other EVs) are single-speed, there's no real gearing factor involved like on ICE, where that velocity and engine speed are in harmony, producing the most efficient engine speed for a gear, too.

All that verbose explanation aside, almost every vehicle will exhibit a decent efficiency difference between 60mph and 75mph. The most efficient speed you can do is the slowest one that it is safe to do.
(Doing economy runs in any vehicle makes you happy to see 50mph roadworks).

[Utumno]

(Doing economy runs in any vehicle makes you happy to see 50mph roadworks).

You’re a monster

[Daveion]

Thought I would add to this part.
"Basically put, if you want to drive twice as fast, you need eight times the power"
Power consumption increases to the velocity squared.
So in mph
56 x56=3136
79x79=6241
All other things being equal travelling at 79mph versus 56 requires twice as much power.
You can calculate the % difference for any speed.
There will be a corresponding speed requiring 8 times the power but it would not be within normal driving range figures.

[monkeyhanger]

Thought I would add to this part.
"Basically put, if you want to drive twice as fast, you need eight times the power"
Power consumption increases to the velocity squared.
So in mph
56 x56=3136
79x79=6241
All other things being equal travelling at 79mph versus 56 requires twice as much power.
You can calculate the % difference for any speed.
There will be a corresponding speed requiring 8 times the power but it would not be within normal driving range figures.

Velocity squared is a major factor, but there's another significant factor at play too - aerodynamics. If I maintain 80mph on the motorway in the Summer, I'll get about 3 miles per kWh. If I do 50mph, I won't get 6 miles per kWh, more like 4.5 miles per kWh.

The velocity squared thing works on a cube, but not properly on an aerodynamic car. For a reasonably slippery modern hatchback, the wind resistance differences between 0mph and 30mph are very low, on a boxy range rover, not so much.

For a car like the ID3, is probably more like (velocity minus 30mph) squared.

There's no arguing that max economy on most cars is around 55-60mph. Sometimes that isn't the case. My 7 speed DSG A4 was more economical at 80mph than 70mph because at 70mph the car spent 20% of its time in 7th (pretty much on a downhill slope where not much torque is required). At 80mph it spent 90% of its time in 7th in the torque band, with only a really steep uphill section making it drop to 6th. Obviously the ID3 has no gear selection, so it has a fixed ratio to suit the speed ranges most people are maintaining most of the time.

[Daveion]

The V2 is because of the drag coefficient.
Its already in the energy equation.
At speeds between say 45 and 90 the square rule works within a few percent.
If weight, rolling resistance, other mechanical losses remain contant with a fixed drag coefficient only the V2 changes.

[sausageroll]

(Doing economy runs in any vehicle makes you happy to see 50mph roadworks).

You’re a monster

I've done a few economy runs over the years. Pre-children, I had a Porsche Boxster that I was hypermiling to the NEC for a bit of fun. Set out aiming for 35mpg, and I loved seeing the 50 stretches on the M5 because in 5th it would bump the mpg right up. Ended up with 43 mpg indicated because of how many roadworks there were

On a normal commute I was used to around 19mpg.

Despite popular beliefs, it's often much more of a skill to drive efficiently than it is fast. Incredible how many everyday folk seem to think mpg (or likely in future, m/kWh) is something that happens regardless of how you drive a car.

[Daveion]

Very nicely put

[G43FAN]

That explains my 3.3 after 6000 miles then...