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3 tips to significantly increase range in winter and message for Tesla

3 tips to significantly increase range in winter and message for Tesla

I figured I would share some of my tips for increasing range in winter (for longer trips). We have an MX 60D, best car ever, do a ton of driving, and live in a very cold place (Montreal). We rarely have range concerns and more importantly, the more we drive our car in the winter, the better we understand how to affect range. So here goes. Don't be shy to correct any of my math/assumptions. Because folks on this forum tend to be :)

First of, here is my understanding of why range can be an issue in the winter time:

1. Cold air is denser, so drag is greater, 15C vs -15C translates to roughly 12% more drag. This is then multiplied by the cube of speed!
2. Heating the cabin is expensive (2-6 kWh)
3. Rolling resistance is usually higher in the winter time due to snow/ice/rain on roads and ice buildup on cars makes them less aerodynamic
4. Finally cold batteries have higher internal resistance and this is elephant in the room! When I start my drive on a cold day (-15C to -20C). My battery will likely be the same as outdoor temperature (slightly higher). At some point this winter we stayed a full week at our cottage at -25C to -35C!. After about 1-2 hours of driving, the battery usually warms up (can be seen by the regen limitation disappearing) and within two hours you have full regen (battery is now >15C). If you have observed this in your car, you probably also noticed that your consumption was at least 2X rated. The heating of the battery comes from the onboard heater (if you have range mode off) but also comes from the battery's internal resistance. Numbers: a 1200 lbs battery needs 19 kWh to go from -15C to 15C (1200lbs*54(temp delta)/3412(BTUs per kWh) and 25 kWh to go from -25C to 15C. So in my MX 60, about half of the capacity can be lost to waste heat. This is far more significant than the 3 other factors listed above.

3 tips for getting near rated range in the winter time (sorted by most impactful):
1. Preheat. A lot. I will preheat (with range mode off) for up to 4-5 hours If I know that I need the range. Ex for a 250 KM drive (My rated is 310KM). If you have a 6 KW charger, you will need 4 hours to to generate 24 kWh or enough to bring your battery to ideal temp. I like to keep my climate setting at 18C when preheating so that the bulk of the power comes from shore and not from my battery. Preheating like this has a night and day effect on range. If you can park indoors, even better. Preheating gives you the thermal storage equivalent of a 25+kWh battery. Try it.
2. Try to not exceed 20-30 KW of power. Specially with a cold battery. So don't accelerate hard, don't regen hard (coast vs regen). This will again limit the power losses in the battery. Bjorn has a great video on Youtube showing how to very quickly heat up your battery by accelerating and decelerating like crazy. Yes, do the EXACT opposite of what he is doing :) What is incredible in his video is seeing how quickly you can heat up a battery by having a heavy foot. That's 10s of kWh lost in minutes ... So go easy. This has also made me a much better/zen driver. My Bernese Mountain dog in the back really likes my driving :)
3. Drive slower. Because of drag being much greater in winter and because of v cubed. CUBED!!!!

If you are still reading, here are some more tips:
1. Use seat heaters. It's by far the most efficient way to heat humans in a Tesla
2. The "% Battery left" in the navigation system needs about 10 minutes of driving to show an accurate estimate, but it works very very well and I use it as my "budget" for fun things like speed and heat
3. Pick your charging stops in a way that your battery is warm upon arrival. This will speed up charging. Ex, I charge at a stop just before arriving to my ski location (fast warm charging) VS charging apres ski (cold battery, slow charging).

Elon/Tesla if you are reading, here is my wish list for some software:

1. Conditioning feature: I want to be able to set my departure time at, say 7 AM, hit "yes" on the popup warning me that this will result in more electricity cost, and have the car (using only available shore power) preheat the battery, then the cabin, then top off the battery so that by 7 AM, I have the optimal conditions and the best best range ever. Heck, I would like the battery heated to 35C-40C, so that this extra heat can be used as cabin heat for the next 1-2 hours. Can you imagine getting better than rated range in -20C!!! Come on Elon.
2. Make chill mode more chill and make chill mode chill Autopilot. I avoid using excessive acceleration and deceleration to improve range. It would be great if Autopilot didn't take my speed setting as a do or die challenge. Allowing +-3 KM from set point would improve range drastically by eliminating needless (60%-efficient-at-best-regen AKA regen) and high KW bursts on small hill climbs. We love Autopilot. I think it's incredible that Tesla was able to develop it so quickly and it's amazing how much safer and easier it makes our drives but my wife and I now do this voiceover/if Autopilot could talk thing and it goes something like this: *deep 8 year old eager boy voice* "You want me to follow that car.... Yah Yah, i can do that i can i can. Go go go... Oh no, oh no, regen regen regen. No wait, wait, i got this, i got this, go go go...." And we're like, Chill dude... Driving under an overhead sign (circa Q1 2017, he doesn't do it anymore): *the same 8 year old with the deep voice* "My mom always said life was like a box of ch... AHHHHH THING!!! THING THING, break break br... oh oh oh wait, where did it go?" And we're like, no Boo (car's name) it was just an overhead sign. It's okay, we still love you.

Hope that was helpful...

Elon is you are still reading:

1. This one is more complicated but can be very impactful for range. I have arrived to destination with 0%-1% left on my battery on MANY occasions with no worries about running out. I use my speed and zen driving as my variables to manage my "budget". It would be great if my Tesla can automatically reduce max power to help automate what I do manually. Guaranteeing arrival time and using the full capacity of the battery. Right now, power limitations only kick in when the battery is very low (too late). Having such a feature would allow users to use up the 10%-20% of the battery that they usually put aside as buffer. To cancel this feature, the user can simply kick down on the accelerator and the limitations would be reset...
2. Unlock Boo and all other 60Ds or just Boo :)
3. Platoon feature: All the hardware and most of the software is already in place to do this.
4. Also Good job, you are killing it.

Bighorn | 26/01/2018

Lots of good suggestions. A little confusion about the effect of velocity on drag. It’s a squared function when calculating energy, where power requirement is cubed. That drops out based on foreshortened duration.

inconel | 26/01/2018

Your Bob sounds exactly like mine. Guess they went to the same school in Fremont.

LTO2 | 26/01/2018

@Im...: Thanks much for sharing your, and your wife’s, learning about cold-weather driving. Reassuring for this 75D owner.

Must work on preheating: during a recent cold snap (a couple of 0-degree F nights in mid-Tennessee), turning on the heater via the app didn’t lead to preheating of my battery pack, at least not sufficiently to avoid the limited regen. However, I wasn’t road-tripping, just driving in the city and back home to a garage and High Capacity Wall Charger.

Cheers!

Bighorn | 26/01/2018

@LT02
The battery pre-heating does not eliminate limited regen. Takes it to about 30kW which is plenty and energy efficient..

AHasse | 27/01/2018

Thanks! As an X owner in Idaho-- these are great tips/suggestions! Hoping @ElonMusk was listening!

Wilber | 27/01/2018

Thanks lm_mx_60D! Planning to take my first trip next week here in chilly Northern California, so will do everything you suggest! I like your software suggestions too!

LTO2 | 27/01/2018

@Bighorn: Thanks for the correction. Every bit helps this ol’ boy...!

burdogg | 27/01/2018

What! You mean I can't get 257 miles in my 90D in the winter unless I drive like a grandma... :)

Sorry, had to say it after all the whining around here about how Tesla lied to them about how far they can go on a charge.

Great write up and great advice. Thanks for putting your time and effort into this, maybe it will help a lot of new owners understand how it all comes together and how to actually really get close to the miles listed :)

markcohen | 27/01/2018

The way that I look at it, having a Tesla is kinda like having 2 cars in 1. It is an incredibly fast, high performance car that is fun to drive. It is also an incredibly energy efficient car. You just can’t get both extremes simultaneously. If you want to accelerate hard and drive fast then yes, your range plummets. If you want to have the very best range/efficiency, you do have to drive gently - and with some practice you can exceed the rated range. And of course, you can just be yourself and 99% of the time just drive and not worry about it as it has enough range for most of us in a typical day.

People have pointed out that ICE cars also have trade offs according to how you drive them. I agree that they do - but not to the degree that the Tesla has. But then again, I don’t know of many ICE SUVs that can do 0-60 in 66% or less of the time that I can with my Lexus SUV AND when I want it to to be 3x more efficient. Pretty impressive.

Coldfire73 | 28/01/2018

One extra tip (at least it seems to work for me) is turning ON Range Mode if you are only driving a short distance.

As under about 20 miles (most of my commute distance) the battery never really warms up enough. So the battery heater is really wasting energy warming the battery for it to then sit and get cold again while at work.

However, remember to turn Range Mode OFF again when charging to enable preheating!

Setting Range Mode is one thing I’d like to see added to the Tesla app. For those times when I forget to turn it off when I get home, and can’t preheat the car from bed
In the morning! #FirstworldTeslaProblems
Lol

mrrjm | 28/01/2018

If you own the performance model just go out and turn the battery heater on for 30 mins. Also helps if you have the 72 amp charger.

Tdreamer | 29/01/2018

I wonder if a flamethrower could be adapted to per-heat the pack?

drdavelynch | 30/01/2018

Great article! Thanks. We will be driving to Sun Valley, ID soon, and I must park my car outside in a lot without a charger. My only option will be a 110 v outlet, and I was thinking I could run a 12 gauge extension cord to the car to keep it trickle charging. Should this work in the cold weather, given the battery temp? Would this be an adequate power source to pre-heat? Thanks for your advice!

Bighorn | 30/01/2018

@drdave
Plug in before the battery gets cold soaked. In MN, I got a message that the power available from 120V was inadequate to heat the battery. The heater requires 6kW and you’re providing less than 2.

michael | 30/12/2018

Great tips. Why do you need to turn off range mode when preheating?

Passion2Fly | 30/12/2018

Range mode will reduce the battery heater power output. By disabling range mode, you make sure that you’re heating the battery as fast as possible.

I also suggest, on performance models, to use the max battery power mode as well while pre heating. It will maximize the battery temperature and have it nice and warm for the cold weather...

ddolapsakis | 31/12/2018

Great advice. I still think that displaying an energy consumption breakdown on the screen is a must and would help educate all of us.
As Bjorn (utube) also points out, using the navigation software helps the car prepare the batteries for fast-charging or even super-charging, as opposed to just driving upto a random charging spot.

ajdelange | 03/01/2019

"1. Cold air is denser, so drag is greater, 15C vs -15C translates to roughly 12% more drag. This is then multiplied by the cube of speed!"

Aerodynamic drag is directly proportional to density and the square of the velocity. The work done (energy used) is the product of the distance traversed and the drag, IOW density times velocity squared times velocity times time. Thus the energy consumed in traveling for a period of time is proportional to the cube of the velocity but is linearly proportional to the air density. The distance traveled in the same time period is velocity times time so the energy used per unit of distance traveled is proportional to the square of the velocity (not the cube) times the density. A 12% increase in air density would thus, ceteris paribus, reduce range to 88% but decreasing speed from 100 km/hr to 50 would, ceteris paribus, quadruple range.

dgriffler | 03/01/2019

Is there a Tesla video or manual entry on installing a front license plate? And do I require third party parts in order to do it safely and reliably?

David Trushin | 09/01/2019

What am I missing. Just screw it into the license plate bracket provided with the car.

Redmiata98 | 09/01/2019

Not all of the cars have the receptacle attached and/or installed.

ratchet | 09/01/2019

Some states require that a front license plate bracket be installed on a vehicle before it can be sold in that state. Others (even some that require a front license plate) leave the bracket as optional which means the owner is liable for any violation of state requirements. When I picked up my MX almost 2 years ago in northern Virginia, they asked if I wanted them to install the bracket. Part of the reason they asked is that the Tesla solution requires making holes in the front bumper so some owners prefer third party solutions that do not attach to the bumper.

monfera.robert | 08/06/2019

"A 12% increase in air density would thus, ceteris paribus, reduce range to 88%" - why is that? If the only power consumption were due to air resistance, then a 12% denser air would lead to a 12% higher energy expenditure, ie. 112% of the baseline (a 1.12 multiple). That translates to a 1/1.12 = 89.3%, close enough.

But air resistance is only one factor. If we can believe this chart http://www.solarjourneyusa.com/EVdistanceAnalysis5.php - at least for the Tesla Roadster (yes, very different car) it takes a quite high speed of about 80mph for drag resistance energy use to match all other losses (tire, drivetrain etc.). I suppose this was tested in fair weather, and while ICE cars can heat the interior with waste heat, an electric car needs to provide it separately, so even at 80mph in the Winter (cold driving is the topic of the article) energy loss from drag is still lower than all other sources combined. But let's assume 50% of the losses are drag related. In this case, the car needs 0.5 * 1.12 (relative) to overcome air resistance, and still the same 0.5 unit (relative) to do everything else, ie. 1.06, yielding an 1/1.06 = 94% range, assuming 80mph and moderate temperature (and a Roadster). In Winter, and at more typical, ie. lower cruising speeds, the likely effect of extra drag coming from denser air is more likely to be a fraction of this 6%, maybe 2..4% depending on circumstances. It turns out that the Model S and Model 3 have a lot lower drag (0.24, 0.23) than the Roadster (0.36) so maybe it's even less. Perhaps yielding a range of 97..99% of that of less dense air, all things being equal, in contrast to your 88% value. Which only strengthens your main point though.

David Trushin | 09/06/2019

Every year since 2013 I have put in a request for a battery preheat function in the car and they still haven't given it to us. Preheating the cabin only goes so far and it's a waste of electricity to heat the cabin for 4 hours just to increase the battery temp a little. The closest they have come is to condition the battery if you navigate to a supercharger. But this is not a good solution because you really want to heat the battery while plugged in. Come on, this isn't rocket science.