Winter - excessive battery range reduction...

[clostridium]

The ideal way to use range mode in the OP's situation (preheat-long drive-park in the cold-drive home), would be to charge and preheat shortly before leaving home with range mode off. Once driving in a warm car, range mode on or off makes a small difference - in general, turn it on if you are warm enough. When you get to your destination and park, make sure range mode is on if you can't plug in. Range mode will stop or slow the battery heater draw on the frozen battery which will make a big difference in consumption on the way home. The motor and inverter will warm the battery naturally (and more slowly) as you drive.

When the battery is frozen, don't preheat, just turn on range mode and drive. Upside, is you'll save a lot of energy, downside is regen will be limited and cabin heater will be slightly reduced in output.

Thanks - that’s the best explanation I’ve heard of how to use range mode effectively.

Just drove the same ~20 mile trip in 10-12 F (or -10 C) - in one direction with preheat at home in insulated but not heated garage and climate left at 64 during drive I got 340 Wh/mi. The battery was not completely heated though. On way home I got 460 Wh/mi after car sat in cold for 9 hours. This despite driving slower and climate set at 60. Range mode was off. Will try with it on for the return trip next time.

Craig

 

[claud_face]

Ok guys.

I arrived in Mauston WI yesterday from Chicago. I am about 10 miles north by Castle Rock Lake.

Anyways. Fully charged to 100%. Preheated while charged for over an hour.

Tried to drive "normally" not thinking too much about range as it was my first trip and the idea behind this car is not to sacrifice driving style/comfort. However, I still drove relaxed and unaggresive due to the fact when I originally calculated 330 capacity at 35% efficiency loss I was very concerned.

Bottom line. I had to stop in Madison. My nav showed a battery capacity of 39% arriving in Madison. That was 25 miles away. Mauston supercharger showed 15%. 2 miles before Madison it showed 35% and 11% at Mauston. To me it was clear it was going to be too close for comfort.


I pulled over. Added 95 miles and drove to destination. In theory if I didn't add the 95 miles I would not have made it by 2 miles.

I only had cabin heater on 70 entire time. Temp outside was basically 10/11F entire trip.

Average speed was 69-77mph.

Trip mileage was 208 miles. Range is 330. Looks like I lost 38% in efficiency.

I expected it but will admit I am slightly disappointed. Wanted that trip on one run but just couldn't do it.


Any other questions. Just let me know.

 

[PhaseWhite]

Ok guys.
I arrived in Mauston WI yesterday from Chicago. I am about 10 miles north by Castle Rock Lake.
Anyways. Fully charged to 100%. Preheated while charged for over an hour.
...
I expected it but will admit I am slightly disappointed. Wanted that trip on one run but just couldn't do it.


Any other questions. Just let me know.

Thanks for the update. It's crazy how much the energy consumption can vary on these cars depending on the situation. I'm in Minnesota in the middle of artic air blast (-2F) and yesterday while I was out about in town I averaged around 350 wh/mi on the first leg of the trip with a fully preheated car (highway driving 15 mi). On the way back I had a cold soaked battery and averaged 550 wh/mi .

To contrast, on my road trip up north this summer I drafted semis as much as I could and saw sustained consumption of 215 wh/mi while drafting... That would imply 390 mile range using 286 wh/mi consumption for the 294 mi EPA range of my MS 90D.

 

[Brian-MS90D]

Ok guys.

I arrived in Mauston WI yesterday from Chicago. I am about 10 miles north by Castle Rock Lake.

Anyways. Fully charged to 100%. Preheated while charged for over an hour.

Tried to drive "normally" not thinking too much about range as it was my first trip and the idea behind this car is not to sacrifice driving style/comfort. However, I still drove relaxed and unaggresive due to the fact when I originally calculated 330 capacity at 35% efficiency loss I was very concerned.

Bottom line. I had to stop in Madison. My nav showed a battery capacity of 39% arriving in Madison. That was 25 miles away. Mauston supercharger showed 15%. 2 miles before Madison it showed 35% and 11% at Mauston. To me it was clear it was going to be too close for comfort.


I pulled over. Added 95 miles and drove to destination. In theory if I didn't add the 95 miles I would not have made it by 2 miles.

I only had cabin heater on 70 entire time. Temp outside was basically 10/11F entire trip.

Average speed was 69-77mph.

Trip mileage was 208 miles. Range is 330. Looks like I lost 38% in efficiency.

I expected it but will admit I am slightly disappointed. Wanted that trip on one run but just couldn't do it.


Any other questions. Just let me know.

You do need to change your driving habits some with the electric care (compared to ICE) in order to maximize your driving range. Decreasing your speed to 70 MPH or under always would make a big difference, especially in the winter when the air is colder, denser, and increases the drag on your car. I set my autopilot on and let the car do most of the work. Your example here is a good one of where driving slower (60 mph, 65 mph?) would have saved you time in total because you likely would have made it without the middle stop.

Also, when posting these details it is helpful if you can use the Trip function in the car and report your wh/mi, that way we can see how much you were actually consuming for the trip.

 

[RDoc]

Every winter this kind of thread gets created and every winter I suggest that Tesla should offer a diesel fuel powered heater. Using battery power for heat winds up not working well and probably releases about the same CO2 as an on board heater would. It would only require a tank holding a few gallons of diesel to make a huge difference in cold weather usability.

Also every winter someone says they power their car completely from their own solar cells, and I'm sure some people do.

A gallon of diesel contains about 38 kWh, say 32 kWh including refinery losses, and produces about 10 kg of CO2. A heater should be at least 85% efficient, so would produce about .36 kg of CO2/kWh. The US grid produces about .32 kg of CO2 per kWh delivered, so with charging losses, about .38 kg C02/kWh. That doesn't include fuel supply emissions which would make it worse.

 

[mknox]

My results are a bit better. I left the Chicago suburbs on December 26th @ 8:00 am. The car had sat out all night unplugged and the temperature was a staggering -20 F (-30 C) when I activated the remote HVAC. I ran the HVAC for half an our, then drove 10 miles to the Rolling Meadows, IL Supercharger. From Rolling Meadows, I drove to St. Joseph, MI, Lansing, MI, Port Huron, MI, Woodstock, ON and then home in the Toronto suburbs. The "warmest" it got on the whole trip was around 0 F. I kept a detailed log sheet and updated at each stop with Rated and Actual (odometer) Miles among other attributes.. For my total trip, I used 36% more Rated miles than Actual miles. When I do that trip in the summer, it is actually very close to 1:1. (On the trip down to Chicago, with temps near the freezing mark, I was about 16% higher (rated vs. actual miles).

In practical terms, however, there is enough buffer in my Supercharger stops that I didn’t have to stop any more frequently, although I probably did have to spend a tiny bit longer at each stop. These are the same charging stops that I make when I travel in the summer.

Daily Consumption while I was in Chicagoland and back here in the GTA over the past couple of days has been ridiculously high in comparison to the long, steady warmed-up drive. I think a lot of people get freaked out by this very high day to day cold weather consumption and believe it translates directly to long-distance travel. It doesn’t. I am highly confident in long distance winter trips. Further, I don’t worry about super high consumption on short winter trips because I don’t care if I use 50% of my battery daily instead of 20% since I have more than enough anyway.

Edit: When we left, our daughter's Honda in the garage was frozen and wouldn't start. They had to get it to the dealer later in the day where, once it warmed up, was fine. Score 1 for an EV in the cold!

 

[AnxietyRanger]

As I've mentioned on this forum before, at least at motorway speeds, I divide range by two during winter to get an estimate.

 

[mknox]

As I've mentioned on this forum before, at least at motorway speeds, I divide range by two during winter to get an estimate.

You will never go wrong with that advice. My five years of experience have told me that 25% of a buffer is usually more than enough. My extreme cold example above of needing 36% more didn't really impact me because with Supercharger spacing, I was still arriving at my planned and typical stops with miles to spare.

 

[AnxietyRanger]

You will never go wrong with that advice. My five years of experience have told me that 25% of a buffer is usually more than enough. My extreme cold example above of needing 36% more didn't really impact me because with Supercharger spacing, I was still arriving at my planned and typical stops with miles to spare.

Yeah, living in a region where charging is sparse, there is some extra safety buffer in my thinking.

 

[Big Earl]

Every winter this kind of thread gets created and every winter I suggest that Tesla should offer a diesel fuel powered heater. Using battery power for heat winds up not working well and probably releases about the same CO2 as an on board heater would. It would only require a tank holding a few gallons of diesel to make a huge difference in cold weather usability.

Also every winter someone says they power their car completely from their own solar cells, and I'm sure some people do.

A gallon of diesel contains about 38 kWh, say 32 kWh including refinery losses, and produces about 10 kg of CO2. A heater should be at least 85% efficient, so would produce about .36 kg of CO2/kWh. The US grid produces about .32 kg of CO2 per kWh delivered, so with charging losses, about .38 kg C02/kWh. That doesn't include fuel supply emissions which would make it worse.

I have a diesel-fired Webasto parking/auxiliary heater in my Touareg and I love it. While it would certainly improve range in the winter, I don’t know how I feel about adding one to what is otherwise a purely electric vehicle.

 

[Zero CO2]

first winter with Model S .... big difference ....350- 400 wh/mi vs. typically 250-300 wh/mi... i realize i do miss something about ICE... there ability to heat the cabin and your feet....floor heat is pathetic

 

[EV-lutioin]

I guess the silver lining is your car started... many ICE cars have difficulty starting in weather that cold. Once I drove in -20 F weather in an Nissan that could produce no cabin heat because is was so cold. We ended up putting cardboard in front of the radiator and it helped a little, but it was down coats and cold feet the whole way. I also has a clutch freeze in my BMW in Colorado, I had to drive without a clutch for the remainder of the drive.

 

[David29]

One thing that I do not think has been mentioned in this thread is tire pressure. Pressure inherently drops with temperature, and low pressure increases energy consumption. And yes, I know, checking tire pressure and adding air in the windy cold these past few days is an unpleasant chore! I postponed it myself, until today when I added 3 or 4 psi.

I have not taken any trips long enough for range to be a concern, and have not noted my energy consumption, but have also seen very high energy consumption during my driving in the Boston area over the past week or so.

Also, I share the observations someone made above about the Tesla heater. On Christmas day, my mother and I were driving about 28 miles from her house to a family party. The car was already warm when I picked her up. At first, the heat was fine. As we passed the half-way point, I noticed the air feeling cold so I adjusted the temperature. I could feel cold air blowing directly on my mother from the dash vent on her side. Cold air was also coming from the rear vents in the center console. Nothing different seemed to happen when i adjusted the temperature. It kept getting colder so I kept turning up the temperature setting. The system was set to Auto, and Range mode was off. By the time we got to the destination, I had turned the heat up to 80F or more, and was still cold. It seemed fine on the trip home, but having no response from the HVAC even when set to 80+ was unnerving.
I have noticed over the years that the sunroof definitely adds to the feeling of cold. I can feel it on my shoulders, even with a coat on. It inly bothers me on long trips on very cold days, so i have not gotten an insulating blanket for it (like Bjorn's, e.g.).

 

[SMSMD]

Pressure inherently drops with temperature, and low pressure increases energy consumption.
I have noticed over the years that the sunroof definitely adds to the feeling of cold. I can feel it on my shoulders, even with a coat on. It inly bothers me on long trips on very cold days, so i have not gotten an insulating blanket for it (like Bjorn's, e.g.).

Drove 2500km from Edmonton, Alberta, Canada to Vancouver and back. Blizzards, Compact ice, frigid temperatures- 30°C was the lowest noted on the dash.
1) Tire pressure inflated to 45 lbs always in winter keeps the low pressure warning showing up.
2) Cold head , shoulders and loss of range is common..solution is bubble wrap the windshield and the glass above the FWD .

 

[AWDtsla]

Things I've learned about Tesla in the winter, despite being told otherwise on this forum:

1. Assuming you are cruising on the highway, preheating does almost nothing. There's a small amount of absolute range you get back, but it doesn't scale across the length of the drive. This is because at highway speed, the cold air is rapidly cooling both the car and the pack. So don't expect it to work miracles. Your consumption by the end of a long drive will hardly be any better.

2. Range mode is unusable. The cabin becomes ridiculously cold, and even if the outdoor temp is high enough, the HVAC becomes unmanageable as the thermostat is effectively broken, in exchange for very little overall savings. You might as well simply turn down the thermostat to your least tolerable temperature, you will waste LESS energy than by overshooting your target temperature repeatedly.

3. Range estimator will not work. You will notice is diverging constantly from it's prediction (at no point in the drive except for near the end is the estimate realistic)

4. Plan for 50% range, and extra long supercharge times unless you are lucky to stop at one after 45+ minutes of driving. There is a double hit on supercharge speed, once for pack temperature, and second for real range added. Correct application of: YMMV.

5. Driving style makes no difference, consumption is dominated by drag.

 

[Snowstorm]

Driving style makes no difference, consumption is dominated by drag

I would disagree with that, as drag increase as the square of speed, so slowing down would help.

I would also suggest that prewarming dies help even for a long trip. This is because the start of the trip is when extra energy is spend for pack heating. Battery to kinetic energy is not 100% efficient so some waste heat is gerenated. At high speed cruise, that would likely have a warming effect on your battery and is likely why regen limitation reduces as you drive and pack warms up.

 

[SMSMD]

There is no mention of Windows fogging. Initially this was a big issue to me. Had to crank up the speed of the fans. Now I use Damp trap moisture eliminatior and it works like magic.

 

[AWDtsla]

I would disagree with that, as drag increase as the square of speed, so slowing down would help.

I would also suggest that prewarming dies help even for a long trip. This is because the start of the trip is when extra energy is spend for pack heating. Battery to kinetic energy is not 100% efficient so some waste heat is gerenated. At high speed cruise, that would likely have a warming effect on your battery and is likely why regen limitation reduces as you drive and pack warms up.

I meant use of the right pedal, not speed. Speed is effectively dictated by the flow of traffic in any given area. I don't view driving slower than the flow of traffic as acceptable in any way.

 

[Gen3]

There is no mention of Windows fogging. Initially this was a big issue to me. Had to crank up the speed of the fans. Now I use Damp trap moisture eliminatior and it works like magic.

What size? How long does it last?

 

[jerry33]

One thing that I do not think has been mentioned in this thread is tire pressure. Pressure inherently drops with temperature, and low pressure increases energy consumption. And yes, I know, checking tire pressure and adding air in the windy cold these past few days is an unpleasant chore! I postponed it myself, until today when I added 3 or 4 psi.

1. At -30 you'll want to add more than 3 or 4 psi. Especially because you're inflating with warm air, so just inflating to 48 psi won't cut the mustard.

2. Don't check the pressures if your car has sat outside in very cold weather (colder than -5 C), ice can form between the valve stem and the valve core and let out air. Use a sealing valve cap to insure a good seal. (The valve cap is actually the primary seal, the valve core is just a convenience to allow pressure checking without losing a lot of pressure.)

3. Range mode works best in town when you are making many stops and short driving. On trips, it doesn't do much (and it never does anything in summer). Setting the charge to end about the time you leave and preheating 30 minutes before leaving do a lot more.