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Oct 2021
9:18am, 20 Oct 2021
491 posts
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fuzzyduck79
I've been getting 3.3-3.4 miles per kWh out of my ID4 - that's with no effort to limit use of air con/heating and average motorway behaviour to other drivers.
Does look like heating the cabin a lot costs some range, but at current usage levels I'm only adding ~45kWh charge a week, which takes 6-7 hours at home, 1-2 overnight charges on the cheap rates.
As the on street charging network rolls out, I can see some headaches where installers encroach on pavement space which can cause a problem. I'd like to see that space protected from car infrastructure, feels like we're still sleepwalking into making everything more car centric and harder for vulnerable road users the way things are going, especially in big cities from the evidence I've seen.
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Oct 2021
9:23am, 20 Oct 2021
15,801 posts
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larkim
I wouldn’t advocate driving at that adjusted style normally, but for a squeeze to efficiency to know that that’s there is useful as an antidote to some range anxiety. I now know that I can potentially squeeze out up to 20% more from the tank in extremis if I need to.
Most of the time I will continue with my usual driving style; swift pull away from the lights, mostly driving at local speed limit without worrying how hard my right foot goes down for small bursts of acceleration etc. My only adjustment has been that 65mph limit on the motorway because a) I’m only the motorway for 15 minutes per commute so the difference between 65mph and 70mph is about only 1 minute in my ETA at home or at work and b) the efficiency impact is significant especially when accumulated over a year of commuting (though in reality, pretty low cost), so I’d rather use less electricity if possible.
I wouldn’t make any compromises in respect of cabin temps at all, and not using the precon is only a temporary measure whilst I’m feeling a bit “rationed” in respect of electricity supply.
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Oct 2021
9:33am, 20 Oct 2021
492 posts
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fuzzyduck79
The impact on efficiency at higher speeds has made me think, ICE drivers doing way in excess of 70mph a lot are burning quite a bit of excess fuel. Which increases CO2 emissions.
It's something I think I have always been vaguely aware of, but it's only now that I am paying attention as range is a hot topic in take up of EVs (even though most ICE cars show range, and the effects are quite similar when you hammer it on the motorway)
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Oct 2021
9:39am, 20 Oct 2021
5,285 posts
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Windsor Wool
We're getting 2.7 miles/kWh out of our Volvo. I suppose me driving at 90 round the M25 to work has a negative impact!
I really notice the difference between my morning and evening commutes though. When the car is cold in the morning I might only get 2.5 miles/kWh on my commute with the efficiency clearly increasing as my journey continues. I then park in an underground car park for the day and get 3.3 - 3.4 on the way home. Even without the ICE to warm-up & lubricate I suppose there's still a lot of benefit over running a warm car than a cold one....
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Oct 2021
10:54am, 20 Oct 2021
15,803 posts
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larkim
Funnily enough, my commute home is less efficient than my commute to work, consistently so. I've put it down to the fact that I live about 80m above sea level whereas work is about 10m above sea level so one is a downhill route and the other uphill.
In terms of ICE cars burning more fuel at higher speeds, I think I was put right on that subject a while back. Whilst objectively pushing a car along at 70mph compared to 65mph takes more energy (though for a shorter period of time) due to things like air resistance squaring with increased velocity, there's something to do with the efficiency sweetspot of ICE technology that means that the impact of higher speed driving is far more significant for EVs than ICEs.
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Oct 2021
11:10am, 20 Oct 2021
7,280 posts
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paul the builder
I imagine that's gearing-related. So there will be 'steps' in the overall mpg curve v. speed for an ICE, but it'll be a continuous line for an EV.
So 40mph in an ICE will be less fuel-efficient than 56mpg, because the engine is still doing 2,500 rpm, but in 4th gear instead of 5th. But I would imagine slower is always more efficient in an EV.
*all number made up for illustration only, but you get the point.
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Oct 2021
11:21am, 20 Oct 2021
15,804 posts
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larkim
Hmm. So why not implement gears in an EV? Or is that a really, really daft quesiton!!
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Oct 2021
11:23am, 20 Oct 2021
15,805 posts
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larkim
Or is it as simple that an ICE is *only* efficient in a band (say) 4000-5000rpm and any use outside of that is very inefficient. Whereas an EV has constant efficiency across all rpms (within reason).
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Oct 2021
11:32am, 20 Oct 2021
7,281 posts
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paul the builder
Or is it as simple that an ICE is *only* efficient in a band (say) 4000-5000rpm and any use outside of that is very inefficient.
Yeah, so this is what determines the shape of the 'mini-curve' of efficiency for each gear individually - there'll be an optimum within each mini-curve, but the higher gear curves are higher up the y-axis on the whole.
Or is it as simple that an ICE is *only* efficient in a band (say) 4000-5000rpm and any use outside of that is very inefficient.
And that would be the intent of the system yes. Modern electric motors are very good for this now; wasn't always the case (pre-EVs).
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Oct 2021
1:33pm, 20 Oct 2021
493 posts
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fuzzyduck79
Energy requirement to keep moving through air is proportional to the cube of velocity
So taking your speed from 70mph to 90mph more than doubles the energy lost to air resistance...and you don't get to save any of that by telling me you got there quicker!
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Fetch Camper Vans
Oct 2024
