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Discussion Starter #1
The GTE driver display shows mpg and mi/kWh.

What exactly are mi/kWh, and what values are people getting?

Yours curiously....
 

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It is a straight measure of the number of miles you are travelling per kWh of electricity used from the battery. This is straightforward and helpful if you are using electric only.

However the way VW have set it up when you use the ICE, the number increases as you have used petrol instead of electricity to power the miles. Conversely the mpg figure goes up when you drive in e-mode as you are using less petrol.
 

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I was getting 4.1-4.2 mi/kWh when I first got the car. However I now have switched the car to kWh/100km so get different figures now.

You can see some figures I got and a comparison between mileage on 18inch and 16 inch wheels here:

Long term mileage,
Now that I have had the 16 inch wheels for a month and a half I have some meaningful mileage data. Here are the long term driving data screen shots:

18 inch Serron from new til 6 May (included 196 delivery miles which somewhat skews the data)
View attachment 12568


16 inch astana wheel since 7 May
View attachment 12569

You will see that I don't do a lot of petrol miles. I still haven't filled up the tank from new.
I have occasionally flipped into 4.2 mi/kWh on the 16 inch wheels but given I have done less than 80 petrol miles which generally increase the mi/kWh this is significantly better mileage.

However downloading data from the new Car-net web portal gives much more accurate information.
I have averaged the kWh/100km data after delivery til change of wheels and then for a period since then. My driving distances and journey profiles were similar between the two, with majority of e-mode driving.

18 inch Serron on Bridgestone Potenza tyres - 20.02 kWh/100km

16 inch Astana on Goodyear Efficient Grip Performance - 16.06 kWh/100km

Obviously the lower the value the better - less energy for a given distance.

The change in wheels and tyres have given me a 19.8% improvement in power consumption on average.

I am very happy with that. It has surpassed my expectations. The best part is that the electric range is increased so I have found myself using only e-mode on more days.
 

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When in e-mode I’m getting about 3.1 during the winter but I leave my A/C on, no point being uncomfortable! In the summer I was getting about 3.8-4.0 as tend to use more open windows than A/C. Worth noting I’m on 17in wheels which I think does make a difference as per @doccb1979 above.
 

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Discussion Starter #5
Thanks for the replies.

So, on my 55 mile commute, which is a mix of pure EV and hybrid, and mainly motorway, I typically get 60-70mpg and 10-12 mi/kWh. I don't pre-heat the car and, in this weather, use the heater/demister/seat warmer whilst in hybrid mode. My GTE is a 2015 model on 17" wheels

Is that mi/kWh good, bad, or average? Or a useless stat given my journey is mixed EV/hybrid?
 

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Are you arriving at your destination with any electrical range remaining?

In my car 6kw of the 8.7kw battery is usable (being checked with VW in a week or so) so 10mi per kw as a mix would equate to 5.5kw of battery usage over the 55 miles, so i'd guess 2/3 miles of range remaining.

60-70mpg seems to be in the right ball park, but if you wanted to confirm your battery performance leave it in E-mode until the battery is flat and let us know how far you've gone before the ICE kicks in.
 

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Discussion Starter #7
So I start my journey with a fully charged battery, and 28 miles range. That drops by 3-4 miles once the heating goes on. Getting to/from the motorway is done in EV, and the rest in hybrid. By the time I arrive I have 1-2 miles EV range left.
 

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The mi/kWh ( or mpg) figures are only useful when reported as pure activities
ie Fully charged car, drive for 15miles just on electricity ( or up to the battery running out) - what is your value?

Likewise, to drive off and immediately put the car into Hybrid, and leave it there, for your journey - what is the mpg value you got.

Otherwise unless I drive exactly the same route as you at the same time of day, our comparisons of mi/kWh or mpg , do not tie up.

Getting above 3 - 3.3 mi/kWh is not easy on my typical routes/profiles, even with pre heating the car.
I have tried hard and got very upper 3 before, and since New Year I once had 21 real miles out of the EV battery.
Having a short downhill 500yds from my house does not help, nor a big roundabout where nippiness is needed with 1/4mile of leaving the workplace.
I have noticed that leaving home with 9/10ths battery sometimes results in higher values ( as I can take advantage of regen more in the first 1-2miles when the battery is full the system does not store it )

But I have not reached the mi/Kwh values that BEV owners seem to get.
Perhaps because a lot of my journeys where I note the value, are short ( sub 12 miles), with big gaps between.
Whereas 75 miles in an eGolf, the drivetrain is warmed, battery system warmed, etc and the car therefore is running more efficient.

I have noticed my mi/kWh can be higher if I drive 20-30 miles in hybrid, recharge to full the little I used, and then set off for a pure EV trip. But then of course everything is warmed up.

I think getting higher than 4 mi/kWh from a BEV ( or PHEV in pure EV mode trips) is probably "good"
( others please comment !! )
 
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