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 a thermal storage equivalent of 25+kWh. 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.
