Battery Efficiency | Range

[MkeChi]

Hello,
i am a newbie Model X 75D owner (20" stock wheels).

I've noted that the best "efficiency" (#miles driven/mile range used) I can get, with good weather and conservative driving is 80-85%.
Now that it's gotten colder in Wisconsin (temps ranging from 10-40 degrees F), my efficiency is down to ~60%.

I know that cold weather is a drag on EV battery performance, but 40% loss seems a bit excessive to me.

Do you think this is typical or is this a defective battery issue?

By the way, over the life of the car, (~4,000 miles), I have an average of 358 Wh/mi, but now I can't get it below 400 Wh/mi consistently.

Thanks in advance for your advice/tips!

I created a document with some anecdotes and specific examples (attached)

 

[BerTX]

Hello,
i am a newbie Model X 75D owner (20" stock wheels).

I've noted that the best "efficiency" (#miles driven/mile range used) I can get, with good weather and conservative driving is 80-85%.
Now that it's gotten colder in Wisconsin (temps ranging from 10-40 degrees F), my efficiency is down to ~60%.

I know that cold weather is a drag on EV battery performance, but 40% loss seems a bit excessive to me.

Do you think this is typical or is this a defective battery issue?

By the way, over the life of the car, (~4,000 miles), I have an average of 358 Wh/mi, but now I can't get it below 400 Wh/mi consistently.

Thanks in advance for your advice/tips!

I created a document with some anecdotes and specific examples (attached)

I'm not a cold-weather driver, so not a great person to answer your questions.

The cold causes several issues for an electric car. The battery is not efficient at cold temperatures, so the Tesla warms the battery, and this warming takes power. It does not warm the battery much when you are not driving -- it doesn't know if you will be using the car in a few hours or in a week, so it doesn't try to guess. Heating the interior does some heating of the battery, but not much. Your most effective solution will be to charge the battery right before leaving, which will warm the battery while the car is plugged in. This doesn't help much with trips not starting from a charger -- you just need to bite the bullet on those, or get some charging at work or regular destinations. Even a regular wall outlet helps some.

Your second range-eater is cabin heat. The Tesla uses a resistance heater, so basically you are warming the car with a toaster. Not terribly efficient. Again, heating the cabin with the car plugged in will help a lot. The seat heaters use far less power, so try using those as much as possible.

Third, all cars get worse mileage in cold weather. At speed, most of your fuel is used to overcome aerodynamic drag. Cold air is more dense, so it creates more drag. Other weather factors like snow or rain increase rolling resistance for the tires and decrease range. Often there is more wind at times in the winter, and a headwind increases your effective speed by the wind speed, so at 50 mph against a 20 mph wind will use the same range as driving 70 mph.

There are disadvantages to electric cars in winter, for sure. You will learn to deal with them as best you can. Focus on the unbeatable advantages, though. Charging at home means never having to stop for gas in the cold. Electric heat means getting into a warm car with defrosted windows.

 

[ShaneX]

I experienced a similar increase in consumption in cold weather.
X90D, typical 350Wh/mile.
in weather between 0-5deg C, consumption was up over 450Wh/mile.

So I did an experiment over the weekend:
-preheated the cabin (so I could leave heating off during driving - heated seats are fine, the consume very little).
-made sure it was charging the hour before leaving (this makes sure the battery is at an operational temperature, so you avoid putting heat into the battery while driving).
-Then drove at 60mph on AP for about 30 minutes.

I got my rated consumption no problem, maybe even a bit lower.

Then I turned on heating, consumption went back up to around 450Wh/mile. And thats with the drivetrain nice and warm from driving.

Conclusion; MX has big interior, huge windscreen, heating both takes a lot of energy.

 

[jdw]

It's normal, especially on shorter and or multiple trips. You can use range mode to lower the battery warming & cabin heat usage which will dramatically increase efficiency in many cases. You might consider displaying range in % as it makes more sense and is less alarming.

My own usage/efficiency over a wide range of temperatures (in degrees C):

 

[qadaemon]

I'd also agree it's normal. Here's my teslafi chart too if it helps:

 

[MkeChi]

Thanks all for the insight. The TeslaFi charts are quite helpful/intriguing. I will need to check them out.

I guess that means I need to work on getting my employer to install charging stations at my work places (I split my time between two locations).
Also, I suppose 200 miles round trip, even in ideal temperatures is not really practical with the 75D. I will need to experiment in the spring when the weather improves.

Once again thanks!

 

[jbwinton]

my new X sucks in freezing cold Chicago. horrible range when it's below 20F and I need to run the heater on high. DID ELON PLAN TO ONLY SELL THIS CAR IN CALIF???

several people commented on a dead battery (or very low) when left at airport. I kinda new at this but isn't there a setting to turn off EVERYTHING. seems to me I saw something on controls for "emergency" use to turn off . would that preserve the battery ???

 

[MkeChi]

my new X sucks in freezing cold Chicago. horrible range when it's below 20F and I need to run the heater on high. DID ELON PLAN TO ONLY SELL THIS CAR IN CALIF???

several people commented on a dead battery (or very low) when left at airport. I kinda new at this but isn't there a setting to turn off EVERYTHING. seems to me I saw something on controls for "emergency" use to turn off . would that preserve the battery ???

Hello, I feel your pain. However, the advice given by ShaneX above really does work and helps tremendously. Unfortunately, for those of use without charging stations at work (like me), it does nothing for the trip home. I personally think a big part of the efficiency loss in cold weather is that there is NO BATTERY REGENERATION when the car is cold. The key here is to charge the car for ~1 hr prior to driving as noted above. PreHeating the cabin for 1 hour may help -but my understanding is that doesn't do much to heat the battery, so the effect is minimal...

 

[MXFan]

If you need 200 miles on a single charge, a X100D does that quite easily, even in winter. Not so much for a X75D.