Has anyone returned their Tesla?

[MrBadger]

I have never owned a car that had a 50% difference in efficiency between summer and winter or any time of the year actually.

And you still don't.

There will be other factors governing this which you may or may not be able to control. The issue is identifying them and changing years of behaviour should you choose. Under many circumstances the little techniques that you learned to use to drive an ICE car will have a different technique more appropriate to driving an EV.

 

[Glan gluaisne]

I have never owned a car that had a 50% difference in efficiency between summer and winter or any time of the year actually.

The heater probably averages somewhere between 1.5 kW and 3 kW in cold weather (hard to see it being much more than this, given how quickly a car interior heats up if a 1 kW fan heater is placed inside it).

That's going to give a battery capacity reduction of between 1.5 kWh and 3 kWh for each our driven, irrespective of speed. If we use a pessimistic reduced battery capacity range impact of 300 Wh/mile, then that equates to a range loss of between 5 and 10 miles per hour driven.

Air density could account for another 8% range reduction, if we assume cold air at 0°C and summer air at 20°C (also a bit pessimistic), so roughly another 19.2 miles range reduction overall, assuming a normal maximum range of 240 miles.

If the car was driven at an average speed of 40 mph, and had a normal range in summer of, say, 240 miles, so was driven for ~6 hours between charges, then in winter the range loss from having the heater on, plus the increased air density, would amount to about 49.2 miles to maybe 79.2 miles.

Hard to see how just the heater, plus colder outside temperature, could reduce range by 50%. It looks as if the most likely range reduction (for an SR M3) might be around 25% to 30%.

 

[mswlogo]

There's a number of points that haven't been mentioned. Personally I see no reason to be uncomfortable in a car and I do set my temp to 22C (2018 S 100D) and usually take it off auto in cold weather so I can set it to give me heat on feet as well +/- seat as an extra. That and window demisters indeed can eat into range. Also i like to be prepared with reserves in case taffic gets stuck in snow/ice and we all end up sitting for an hour while it's sorted - and yes an extra blanket in the boot for a long trip/commute from home is worthy. I;d rather have a contingency for a splash and dash somewhere than rough it - but then I'm knocking on in years.
The other point about owning the car for 10yrs. It's a computer on wheels and will be obsolete well before then as well as Tesla's high workshop and parts prices so keeping it out of warranty may not be such a good idea.
At the moment the actual cost of the extra leccy for the heaters isn't too bad and you can cook the car up before you leave. There's also consideration that in time your works or local authroities may/may not provide some charging facilities but you can't bank on it.
No one can tell you whether or not to swap the car - a personal decision. Whether you contract with Tesla allows you to is something you have to check with them.

He’ll be out of warranty in less than 3 years with his commute. What then?

It boggles my mind why anyone would buy a crippled SR with a 70 mile commute.

 

[ElectricJoules]

Air density could account for another 8% range reduction....

I thought the reduction in efficiency was due to the temperature of the battery. Cold batteries just don't work very well. I'm not sure air density has anything to do with it, but I'm happy to learn something new.

 

[Yev000]

I got an SR+ with a 45 mile commute, round trip. With the recent software update set to hold and AC set for manual fan 1 and 21 C I get about 280w/mile average with 100ft elevation. That's about 70% efficiency on a cold morning, but that would average close to 80% if it was a longer commute.

Then going back -110ft elevation I get about 80%.

That's going 70-80 for motorway stretches which is probably 20% of the commute.

Biggest thing that kills it is heater + fan and standing still. Preheat (off charger) costs me anywhere between 1 and 2 KWh, which is 2-4% for an SR+. That's about 1 hour charging from a 3 pin plug. And of course during the commute that same heater is using a fair bit over the 1 hour I'm driving.

If you brake it down, 1KWh for 12 min of pre-heat (not max defrost) to take it from 6C to 20C. Then 6KWh to drive for 50 min. I'm betting at least another 1 KWh was heater alone. If you got that on 25C then it would easily be double.

So if I didn't pre-heat and used 8KWh instead of 6 KWh for my morning commute that would take it down to 50% efficiency you are seeing. But you won't see that going back, unless you shoot off the line for every light and go 90 on the M roads.

I also would not worry much about battery degradation as long as you keep it between 10 and 90.

 

[Glan gluaisne]

I thought the reduction in efficiency was due to the temperature of the battery. Cold batteries just don't work very well. I'm not sure air density has anything to do with it, but I'm happy to learn something new.

A large part of the total drag of any car moving at speed is aerodynamic drag. This is why manufacturers wind tunnel test designs and aim to minimise the drag coefficient, Cd. The formula for aerodynamic drag is 0.5*ρ*Cd*A*V²

where:
ρ is the air density, in kg/m³
Cd is the non-dimensional drag coefficient
A is the projected frontal area of the car, in m²
and V is the velocity of the air moving past the car (may not be the same as the car speed over the ground)

From this, it's clear that aerodynamic drag is linearly proportional to air density. At 20°C the air density will be about 1.2041 kg/m³, at 0°C this will have increased to about 1.2922kg/m³, so the aerodynamic drag for any given car at any given speed will increase by about 7.3% when it's 0°C outside, when compared to when it's 20°C outside.

 

[ivangr]

I have the SR+ and absolutely love it.

My only problem is the range as i’m doing about 70 miles commute every day and its costing me 140 miles in range, believe this is mainly because of the weather, i have the heating on auto set to 25 and heated seats on low. my concern with this is that at the moment its manageable but in the future with degradation this could be an issue and i’m looking to keep the car for 10+ years.

I’m now considering getting a refund within the next couple of days and saving up for the long range model.

I’m just wondering of the returns process is simple enough as i read the conditions online but it talked about if you have an incentive then you cant have a refund, is that correct? Surely most tesla have the ev incentive.

Any help would be much appreciated

Regarding degradation, I've read that in the first 100k miles you can expect 2% degradation which will be the largest degradation jump. After that it apparently doesn't degrade at that rate. You can search twitter for people talking about their experience pushing their model 3's over 100K mileage done.
The recent additional miles/charge update has already nullified this future loss for me.

The Edinburgh SC told me that they have a 2014 loaner Model S that only gets supercharged and is generally 'abused' charging wise. They say they think it's dropped 10 miles in that time, if it dropped at all.

A lot of degradation comes from heat on the batteries. Tesla are the leaders in battery cooling as they use a very advanced liquid cooling setup (the Leafs don't for example). For me the battery lifetime is not a worry.

AND. If the worst happens and you need a new battery pack it's apparently currently sold at a cost of $7000. Although I'm yet to hear of anyone having to buy one. The cost of that should go down in time. If you can still buy a Model 3 battery pack 10 years from now is another question of course.

All in all, I would rather worry about the bodywork and seats surviving 10+ years tbh.

 

[ElectricJoules]

A large part of the total drag of any car moving at speed is aerodynamic drag. This is why manufacturers wind tunnel test designs and aim to minimise the drag coefficient, Cd. The formula for aerodynamic drag is 0.5*ρ*Cd*A*V²

where:
ρ is the air density, in kg/m³
Cd is the non-dimensional drag coefficient
A is the projected frontal area of the car, in m²
and V is the velocity of the air moving past the car (may not be the same as the car speed over the ground)

From this, it's clear that aerodynamic drag is linearly proportional to air density. At 20°C the air density will be about 1.2041 kg/m³, at 0°C this will have increased to about 1.2922kg/m³, so the aerodynamic drag for any given car at any given speed will increase by about 7.3% when it's 0°C outside, when compared to when it's 20°C outside.

Thanks Jeremy, a very valid point. Thank you for educating me

 

[elecTED]

The seat heaters are much much more efficient so a cabin temperature of 18-20 with fan set to low and seat heaters on max will be way better than a cabin temp of 25 with seats on low.

Apart from my wife, I didn’t think there was anyone else out there who sets car/house temp to 25!

I’m comfortable with a cabin temp between 19-20. (I like house temp to be 21 - have a Nest so can turn down the temp remotely when she whacks it up to 27.)

 

[Glan gluaisne]

Thanks Jeremy, a very valid point. Thank you for educating me

No problem, it came as a surprise to me when I first noted the strong correlation between fuel consumption and summer and winter temperature, when I bought my first Prius in 2005. I started logging the consumption data, and as I was commuting ~40 miles each way each day, the the data seemed reasonably reliable. This was the pattern of consumption, which happens to match very well with the change in temperature through the seasons. It convinced me that increased drag from cooler air seems to play a significant part. As a pilot, I'd already experienced the significantly increased lift in cooler air (and the converse, too), so this seems pretty logical:

 

[tess19]

I get between 12mpg and 35mpg from my 3.0L Audi diesel so the temperature can make a huge difference to efficiency of all ICE and EV.

Slightly off topic.... if the car has finished charging but the charger is still plugged in, will it use the battery to warm up the car or will it draw power from the charger?

 

[pgkevet]

AND. If the worst happens and you need a new battery pack it's apparently currently sold at a cost of $7000. Although I'm yet to hear of anyone having to buy one. .

AFAIK the pack is bricks into 4 subunits inside the whole shebang which in the case of the 3 also includes the supporting management computers. I heard it was only a subunit that was $7K

 

[Adopado]

My view is that people seem to be very focussed on the change in car efficiency when driving an EV in cold weather, but don't seem to be anywhere near as focussed on the pretty similar change in efficiency in an ICE car in cold weather. No idea why, as all cars perform less efficiently in cold weather. Just air temperature (or more accurately density, which is a function of temperature) makes a difference of around 8% or so between winter and summer, and then when the use of heaters, deicing, demisting etc is factored in that adds another big efficiency hit.

I'd like to agree but that's not quite how it is. Ironically the ICE car advantage in winter is because it uses it's fuel so inefficiently. At other times of the year that inefficiency is loads of heat that gets wafted into the atmosphere, giving no advantage to vehicle or driver. In winter that same heat can instead be channelled into the car to heat it up "for free". In other words the ICE car doesn't use significantly more fuel to heat the car in winter ... it just kicks out less heat into the atmosphere. There is effectively no MPG hit from running the heater full blast. Of course there are other aspects of winter that affect both cars similarly but in an EV there's no getting away from the fact that if you want heat you have to use up extra fuel that you wouldn't normally need to use to get it. We even use fuel direct from the grid that we wouldn't otherwise use, going nowhere, just pre-heating the cabin and battery.

 

[Jason71]

My view is that people seem to be very focussed on the change in car efficiency when driving an EV in cold weather, but don't seem to be anywhere near as focussed on the pretty similar change in efficiency in an ICE car in cold weather. No idea why, as all cars perform less efficiently in cold weather. Just air temperature (or more accurately density, which is a function of temperature) makes a difference of around 8% or so between winter and summer, and then when the use of heaters, deicing, demisting etc is factored in that adds another big efficiency hit.

Poorer efficiency in cold weather is just something we have to live with, no matter what we drive. By the same token, how many ICE cars always deliver their stated MPG, either in summer or winter? My experience is that none I've owned have come close to being able to perform as advertised in terms of economy. Might be to do with the way I drive not matching the driving pattern used for the testing, or it may just be that the testing pattern of use can be tweaked by the manufacturers to give the best possible figures.

At the risk of stating the obvious ICE cars have more range and take seconds to recharge at the many many petrol stations that exist. So the penalty for poor efficiency is only financial. I have not seen anyone on here bemoaning the increased winter cost of fueling their EV. People are only bothered about efficiency since it is directly proportional to range and like it or not range matters especially if you travel places like I do where super chargers don't exist and any form of rapids are few and far between. If I can't do my 130 mile commute driving it like I stole it will ruin my whole week

 

[MelT3]

A large part of the total drag of any car moving at speed is aerodynamic drag. This is why manufacturers wind tunnel test designs and aim to minimise the drag coefficient, Cd. The formula for aerodynamic drag is 0.5*ρ*Cd*A*V²

where:
ρ is the air density, in kg/m³
Cd is the non-dimensional drag coefficient
A is the projected frontal area of the car, in m²
and V is the velocity of the air moving past the car (may not be the same as the car speed over the ground)

From this, it's clear that aerodynamic drag is linearly proportional to air density. At 20°C the air density will be about 1.2041 kg/m³, at 0°C this will have increased to about 1.2922kg/m³, so the aerodynamic drag for any given car at any given speed will increase by about 7.3% when it's 0°C outside, when compared to when it's 20°C outside.

Well I can honestly say all of this is way over my head. For us lesser mortals who don’t understand physics and techie-talk, I suppose the gist of it is ‘more heating In car = less energy left in battery’. Simples!

 

[Glan gluaisne]

Well I can honestly say all of this is way over my head. For us lesser mortals who don’t understand physics and techie-talk, I suppose the gist of it is ‘more heating In car = less energy left in battery’. Simples!

Perhaps more importantly, as an aerodynamic drag increase requires a much larger increase in energy consumption for a given speed, driving slower always reaps a significant decrease in energy ue for any given distance, and this is more significant at low outside air temperatures.

The power needed to overcome aerodynamic drag is proportional to the square of airspeed (so double the speed needs four times the power) and the energy used to overcome aerodynamic drag is proportional to the cube of airspeed (so double the speed for a given period of time uses eight times more energy).

Slowing down, even by a relatively small amount, will save a significant amount of energy (battery capacity, or range).

 

[kingkong5]

I hope you are able to make the right decision on keeping or returning the car within your return period. I know it may not be exactly the same, over here in the States I did return my Model 3 and was so easy. Initially I bought a Model S for my wife, then we liked it so much, I bought myself a Model 3. While a wonderful car, for our driving style and use, it turned out the Model S was a better fit, so I wanted to return the Model 3 so I could pick up my own Model S.

All I had to do was alert the Sales Center within the 7 day period (I did it on Day 5). I brought the vehicle back that day, and they had me sign 3 documents that would reverse the entire process. It was very important that I didn't use the VIN on the vehicle to apply for any rebates from the state of California, or the utilities, as it would then invalidate that rebate for the next purchaser of the vehicle. All of the DMV paperwork was reversed with these 3 documents. They said it would take about 30 days for the full refund to credit back to my accounts, and sure enough, on Day 30 all of the down payment and deposit funds were reversed back.

Good luck in your decision!

 

[Adopado]

Hard to see how just the heater, plus colder outside temperature, could reduce range by 50%

I think you might have conflated 2 different posts here! I mentioned the heater difference (to an ICE) but I'm definitely not in the 50% reduction camp!

 

[redan]

I have the heating on auto set to 25 and heated seats on low.

The heater uses a lot more energy than the heated seats. Lower your heat and raise your heated seats to medium or high and you'll notice a big improvement in energy consumption.

 

[Glan gluaisne]

I think you might have conflated 2 different posts here! I mentioned the heater difference (to an ICE) but I'm definitely not in the 50% reduction camp!

Not at all, this is the post I referred to:

I have never owned a car that had a 50% difference in efficiency between summer and winter or any time of the year actually.