EV range: real v claimed

[Deleted User 1874]

Anyone who drives an EV knows that ambient conditions greatly affect range. So unless those "real world" tests were carried out at exactly the same ambient temperature then they are not comparable to each other or the WLTP figures.

Unfortunately there is no reference in the What Car tests to what ambient temperature their tests were carried out at. I suspect they just did the tests over a period of time along a specific test route regardless of weather, making some cars look relatively better or worse. For example I can drive my Tesla along the same route in summer and winter and see maybe a 30% difference in range. It's something you just have to be aware of with EVs and the WLTP figures are just an industry test standard for comparative purposes only.

Here are some other "real world" tests conducted in Spain and here the cars were much closer to WLTP figures (in some cases they actually exceeded them). But Spain is usually warm and sunny, which is ideal for optimum EV range!

https://www.thejournal.ie/autobest-ev-t ... 6-Jul2018/

[Nuclear Nick]

Peteski - is that range difference summer/winter purely due to battery efficiency? That is, not taking into account air/con or heating etc.

[Ray G]

Was just going to post about fuel consumption then read this. The fuel gauge on my GTS is criminal. It drops from estimated 250 to 200 miles (approx example) within the first 10 miles of driving (even if not driven hard).
Never been too bothered over mpg and wont be trading in any time soon but the gauges are a joke and this is probably the most uneconomical modern car I have owned.

I'm going to go out on a limb here....your fuel gauge is not simply a stick which reads the level in the tank. The car's onboard systems will calibrate your range depending on a whole range of factors. It's no fluke that if you sit the car at 60mph on a clear motorway your range data starts to increase. My S, on a quarter tank may still show 100 + miles to empty after a motorway journey. Once in London traffic...that number will be smashed to pieces!!

Equally, it's no fluke that if you're in a 2 tonne SUV with a 3 litre twin turbo petrol sitting in front of you in stop start heavy traffic, where occasionally you accelerate in Sport out of frustration (please don't lie...everyone does it!), your range data will fall because your fuel consumption will be heavier. Sorry to break that all to you!

Couldn't agree more. Many is the time that I have come back from a steady motorway drive of about 100 miles with more miles apparently left in the tank than when I started.

[Col Lamb]

Pretty much the same 22 mpg running with a light right foot, running on the super unleaded which also makes a difference roughly 10p a litre difference than normal 95, adds around £ 7.00 difference at fill up, however I’m sure the upgrade I made had a impact on fuel consumption sunroof, 21s , 18 way seats. And the heavy spare 18 inch wheel. Although consumption is a individuals driving technique. Big shock coming from a equally powered diesel car.

It gets worst.

I record the mileage, fuel fills etc and over 18 months I found that the MFD mpg is at least 3mpg more than actual.

Your will probably be similar.

But, its a Porsche and we are not really bothered about mpg are we?

[Deleted User 1874]

Peteski - is that range difference summer/winter purely due to battery efficiency? That is, not taking into account air/con or heating etc.

The battery heater can use up to 6kW of power, but that is only required initially to get you moving and then the battery is effectively self-warming while driving. So this loss can be mitigated by warming the battery while still plugged into the mains. The cabin heater can also use up to 6 kW and obviously requires continuous use throughout your journey, although at a much lower power level. It's probably significant, but I don't know how the heater power compares to A/C power in the summer months. But they must cancel out to some extent. Here is an article discussing the heater power usage in a Tesla:-

https://www.teslarati.com/energy-saving ... t-heaters/

I don't believe battery efficiency changes very much from say 10-25 degC, but it has to be kept well above freezing all the time and it needs to be warm enough to accept rapid charging above 100 kW. So the battery management system works to keep the battery in that ideal temperature range. So once you get into ambient temperatures much below 10 degC then battery heating becomes more critical, while cabin heater power goes up too.

My consumption on short local trips typically goes from around 380 Wh/mile in summer to 470 or more in winter, so an increase of around 24%. In terms of range, I lose around 30-40 miles on my 75 kWh battery, so when comparing range with a competitor EV or any kind of standard industry test like WLTP it is important to know what temperature the test was done at. I presume WLTP will be carried out at some nominal temperature like 20 degC, so any "real world" test conducted in winter is likely to look bad. It would explain the very different results What Car? reported vs the Spanish test I linked to above.

[GMAN75]

Speaking of Tesla, here's its "fix" relating to cold weather issues on its Model 3.

You're kidding...!

https://electrek.co/2018/11/22/tesla-mo ... er-issues/

[Deleted User 1874]

Speaking of Tesla, here's its "fix" relating to cold weather issues on its Model 3.

You're kidding...!

https://electrek.co/2018/11/22/tesla-mo ... er-issues/

LOL. Actually had a similar issue on several Porsche 911s. The frameless windows used to be a nightmare in winter and I had several complete failures of the window retraction system. It was never a good look with the glass on the outside of the window seal

The Model X has frameless windows too, but they are working well.

[Nuclear Nick]

Peteski - is that range difference summer/winter purely due to battery efficiency? That is, not taking into account air/con or heating etc.

The battery heater can use up to 6kW of power, but that is only required initially to get you moving and then the battery is effectively self-warming while driving. So this loss can be mitigated by warming the battery while still plugged into the mains. The cabin heater can also use up to 6 kW and obviously requires continuous use throughout your journey, although at a much lower power level. It's probably significant, but I don't know how the heater power compares to A/C power in the summer months. But they must cancel out to some extent. Here is an article discussing the heater power usage in a Tesla:-

https://www.teslarati.com/energy-saving ... t-heaters/

I don't believe battery efficiency changes very much from say 10-25 degC, but it has to be kept well above freezing all the time and it needs to be warm enough to accept rapid charging above 100 kW. So the battery management system works to keep the battery in that ideal temperature range. So once you get into ambient temperatures much below 10 degC then battery heating becomes more critical, while cabin heater power goes up too.

My consumption on short local trips typically goes from around 380 Wh/mile in summer to 470 or more in winter, so an increase of around 24%. In terms of range, I lose around 30-40 miles on my 75 kWh battery, so when comparing range with a competitor EV or any kind of standard industry test like WLTP it is important to know what temperature the test was done at. I presume WLTP will be carried out at some nominal temperature like 20 degC, so any "real world" test conducted in winter is likely to look bad. It would explain the very different results What Car? reported vs the Spanish test I linked to above.

All interesting stuff, thanks!

One description I saw of WLTP quoted a temperature range of 14C to 23C for the test.

[Deleted User 1874]

All interesting stuff, thanks!

One description I saw of WLTP quoted a temperature range of 14C to 23C for the test.

That makes sense on the WLTP test, the range quoted for my car would be very optimistic in the current weather, but achievable in the summer months if driving sensibly and staying strictly within legal limits! So I don't think WLTP figures are that far from the truth, but they are not realistic for all weather conditions and driving styles. Car magazines should be more thorough in their "real world" testing and point out the factors that significantly affect range. As for the likes of the Sun reporting, for them it's just another click bait headline with very little substance.

It's been a bit of a learning curve for me over the last year. I'm loving the remote pre-heating functionality right now!

[Dandock]

Was just going to post about fuel consumption then read this. The fuel gauge on my GTS is criminal. It drops from estimated 250 to 200 miles (approx example) within the first 10 miles of driving (even if not driven hard).
Never been too bothered over mpg and wont be trading in any time soon but the gauges are a joke and this is probably the most uneconomical modern car I have owned.

I'm going to go out on a limb here....your fuel gauge is not simply a stick which reads the level in the tank. The car's onboard systems will calibrate your range depending on a whole range of factors. It's no fluke that if you sit the car at 60mph on a clear motorway your range data starts to increase. My S, on a quarter tank may still show 100 + miles to empty after a motorway journey. Once in London traffic...that number will be smashed to pieces!!

Equally, it's no fluke that if you're in a 2 tonne SUV with a 3 litre twin turbo petrol sitting in front of you in stop start heavy traffic, where occasionally you accelerate in Sport out of frustration (please don't lie...everyone does it!), your range data will fall because your fuel consumption will be heavier. Sorry to break that all to you!

Couldn't agree more. Many is the time that I have come back from a steady motorway drive of about 100 miles with more miles apparently left in the tank than when I started.

+1