70D and Winter Performance/Range

[JeffS]

Just did a round trip Milwaukee to Chicago over the weekend in subzero temps. Trip 1 was -2deg F. Trip 2 was -4deg F. Trip 1 avg 444wH/mi. Trip 2 avg 465wH/mi. Both running 70-80mph. Range mode on, cabin temp 71, rear defrost and seat heaters on.

We were at the CHI boat show in the loop. So we left the car at the Tesla store there, and Uber'd to and from the show. Was able to leave the car plugged in to minimize the cold soak a bit. Plus, when we left to go home, we were almost fully charged. When it's this cold, I charge at a lower rate so that it's charging longer. In this case, I selected 18amp charging so that it would take 7 hours to charge to 80%. When charging, heat is being produced, which helps keep the battery warmer.

In both cases, the first 20miles or so were restricted output and regen due to the cold.

For perspective though, please remember, there are only 10 - 20 days a year when we have to deal with the ultra-cold temps. The other 350-or-so-days...we're everywhere from cold in the high teens morning drive to highs in the low 30's on the way home... To moderate. To summer for a couple of days.

In my family, we have had Volts since 2012. During the winter of 2013-2014 when the cold waves were breaking records left and right, the EV did struggle. Even though the Volt has a gas generator to produce heat and eliminate any range issues, I was obsessing over my EV vs. Gas stats. One very cold weekend when temps weren't even hitting -10F for highs, for travel to Minneapolis and back, I decided to just spend $45 and rented a Chevy Malibu from Enterprise for the weekend. I was happier. My car was happier. And it was only $45. Just sharing...for what it's worth.

 

[RockinWithKids]

Just did a round trip Milwaukee to Chicago over the weekend in subzero temps. Trip 1 was -2deg F. Trip 2 was -4deg F. Trip 1 avg 444wH/mi. Trip 2 avg 465wH/mi. Both running 70-80mph. Range mode on, cabin temp 71, rear defrost and seat heaters on...

Thanks JeffS. For clarification this MKE/CHI trip was in an S85?

The rental car is absolutely in play. 5 - 10K gets you a lot of good rental days.

 

[JeffS]

Yep - my S85.
From my research, the dual drive is rated longer range due to the torque sleep feature. But it's only about 5-8% if my math is right. From my experience, really cold is really cold and that trumps a lot of other factors. In my opinion, it trumps all of the other factors. No matter what propulsion or fuel - the efficiency of the device is at its worst when temps are below zero deg F.

I'm glad you have rental-cars in your decision process. I've had lots of conversations with folks that just can't get over the hurdle of EV's reduced range in super-cold weather. When completely considered though, the number of times that an alternate plan...like a rental car...has to be enacted is maybe 2 or 3 times over the life of the car. Yet they go buy an ICE because...well...that's just too inconvenient. Thousands of days of driving in moderate or warm weather burning gasoline for no reason, because...well...I might have to travel on a really cold day sometime in the future once or twice... It's just non-sensical to me. Glad you are open to it.

 

[RockinWithKids]

Yep - my S85.
From my research, the dual drive is rated longer range due to the torque sleep feature. But it's only about 5-8% if my math is right. From my experience, really cold is really cold and that trumps a lot of other factors. In my opinion, it trumps all of the other factors. No matter what propulsion or fuel - the efficiency of the device is at its worst when temps are below zero deg F.

I'm glad you have rental-cars in your decision process. I've had lots of conversations with folks that just can't get over the hurdle of EV's reduced range in super-cold weather. When completely considered though, the number of times that an alternate plan...like a rental car...has to be enacted is maybe 2 or 3 times over the life of the car. Yet they go buy an ICE because...well...that's just too inconvenient. Thousands of days of driving in moderate or warm weather burning gasoline for no reason, because...well...I might have to travel on a really cold day sometime in the future once or twice... It's just non-sensical to me. Glad you are open to it.

Thanks for the clarification. Living in Minnesota, where the highs haven't been above 0F for the last 3 days, I have to be open to it - especially since we'll be a Leaf/Tesla household. Right now we are a Leaf/Prius household.

FWIW... with the tribal knowledge of TMC I have come up with the following worst case hypothetical scenario in a 70D:

• wH/mile = 500
• Usable battery for driving = 90%
• State of Charge of 100% = 126 miles
• State of Charge of 80% = 101 miles

It would totally suck to have to wait for a 100% SOC to get from the Eau Claire SC to my home (118 miles) but... as you said... it may happen 1 - 3 times over 10 years - with this past weekend perhaps being one of them.

 

[Malujerry]

70D, 21in rims, 32F, 80 mph, minimal wind, clear roads, Long Island for a 58 mile trip
minimal lowest fan speed on hi heat used periodically (maybe 25 mins total of 50 min trip)
no use of heated seats, maybe 10 mins of steering wheel heat.
around 380wh/mile, started at rated 218, finished 135 miles.used 83 miles for a 58 mile trip.

 

[RockinWithKids]

70D, 21in rims, 32F, 80 mph, minimal wind, clear roads, Long Island for a 58 mile trip
minimal lowest fan speed on hi heat used periodically (maybe 25 mins total of 50 min trip)
no use of heated seats, maybe 10 mins of steering wheel heat.
around 380wh/mile, started at rated 218, finished 135 miles.used 83 miles for a 58 mile trip.

Thanks!

 

[ReddyLeaf]

Sorry to not have more accurate numbers, but....

I just finished a 3000 mi RT tour from WA State to Tucson, AZ in the 70D. Temps only dropped as low as 20 F, so certainly not applicable to MN winter temps. However, as others have said, it's not always just the ambient temperature since you can time charging to keep the battery warm. The worst leg was the 150 mi from Tremonton, UT to Twin Falls, ID into the wind. We stopped for the night in Tremonton as the snow was starting. Had about 3" overnight, but clear in the morning. Left the car on the SC all night (Yes, I know this seems like poor charging etiquette, but the other seven stalls were empty and anyone arriving later would be spending the night too). The next morning we drove a couple of miles to warm up the battery, then returned to the SC and charged for another 20 min to continue preheating. Started the drive in the 70-80 mph range, but quickly dropped down to 60-65 mph. Once the 30 mph wicked wind of the west hit, and the roads turned to packed snow and ice, we dropped down to 50-60 mph. We watched the energy graph closely, used NO heat (except seat heaters on "1") the entire trip, and struggled on fully expecting to either drop speeds or stop at one of two plugshare options. Once we hit the I-84/86 intersection, we drove straight into the wind and the car seemed to perform better. The earlier cross winds seemed to buffet the car around more than the straight on winds, perhaps causing us to use more energy. Another factor was that the roads cleared up, so less drag from the compact snow and ice. Anyway, we arrived at the Twin Falls SC with about 5% battery, so maybe a 10 mi buffer. The wind effectively turned a 2 hr trip into a 3 hr trip.

Anyway, to summarize, 150 mi, 20-30 F, 30 mph head wind, avg speed was close to 55-60 mph. I've got 4+ years of Leaf driving experience, so I know what I'm doing. This was a bit of a nail biter due to the remote area, winter weather, and lack of secondary charging options. However, since we were on a 3000 mi tour, we were prepared with chains, a snow shovel, winter boots/clothes/gloves, sleeping bags, water/food, extension cords, etc. It's always a good idea to be prepared, but it's even better not to have to use it.

Edit: Oh, I forgot we had another trip from Pasco, WA to the Ellensburg, WA SC (about 120 mi). Temps got down to 6 F, during the drive, but since we started from our garage, the battery was a bit warmer. I timed our 120 V 12 amp charging to finish just before leaving, so certainly not much warmer than the 30-40 F garage ambient. Again, no problems, using all of the heat we wanted and arriving with about 15% battery. The car quickly supercharged in about 30 min for the next leg to Seattle. In contrast, another Tesla that spent the night out at 6 F, needed about 2 hours of charging to slowly warm the battery. So keep your battery warm and long trips will be pretty easy. However, multiple start/stop short trips in town at very low temps will cut the range down by as much as 1/2 or maybe even more depending on conditions.

 

[RockinWithKids]

Sorry to not have more accurate numbers, but....

I just finished a 3000 mi RT tour from WA State to Tucson, AZ in the 70D. Temps only dropped as low as 20 F, so certainly not applicable to MN winter temps. However, as others have said, it's not always just the ambient temperature since you can time charging to keep the battery warm. The worst leg was the 150 mi from Tremonton, UT to Twin Falls, ID into the wind. We stopped for the night in Tremonton as the snow was starting. Had about 3" overnight, but clear in the morning. Left the car on the SC all night (Yes, I know this seems like poor charging etiquette, but the other seven stalls were empty and anyone arriving later would be spending the night too). The next morning we drove a couple of miles to warm up the battery, then returned to the SC and charged for another 20 min to continue preheating. Started the drive in the 70-80 mph range, but quickly dropped down to 60-65 mph. Once the 30 mph wicked wind of the west hit, and the roads turned to packed snow and ice, we dropped down to 50-60 mph. We watched the energy graph closely, used NO heat (except seat heaters on "1") the entire trip, and struggled on fully expecting to either drop speeds or stop at one of two plugshare options. Once we hit the I-84/86 intersection, we drove straight into the wind and the car seemed to perform better. The earlier cross winds seemed to buffet the car around more than the straight on winds, perhaps causing us to use more energy. Another factor was that the roads cleared up, so less drag from the compact snow and ice. Anyway, we arrived at the Twin Falls SC with about 5% battery, so maybe a 10 mi buffer. The wind effectively turned a 2 hr trip into a 3 hr trip.

Anyway, to summarize, 150 mi, 20-30 F, 30 mph head wind, avg speed was close to 55-60 mph. I've got 4+ years of Leaf driving experience, so I know what I'm doing. This was a bit of a nail biter due to the remote area, winter weather, and lack of secondary charging options. However, since we were on a 3000 mi tour, we were prepared with chains, a snow shovel, winter boots/clothes/gloves, sleeping bags, water/food, extension cords, etc. It's always a good idea to be prepared, but it's even better not to have to use it.

Edit: Oh, I forgot we had another trip from Pasco, WA to the Ellensburg, WA SC (about 120 mi). Temps got down to 6 F, during the drive, but since we started from our garage, the battery was a bit warmer. I timed our 120 V 12 amp charging to finish just before leaving, so certainly not much warmer than the 30-40 F garage ambient. Again, no problems, using all of the heat we wanted and arriving with about 15% battery. The car quickly supercharged in about 30 min for the next leg to Seattle. In contrast, another Tesla that spent the night out at 6 F, needed about 2 hours of charging to slowly warm the battery. So keep your battery warm and long trips will be pretty easy. However, multiple start/stop short trips in town at very low temps will cut the range down by as much as 1/2 or maybe even more depending on conditions.

Thanks!

 

[chriSharek]

I'm in Florida but after reading this thread, I'm so glad I ordered the 85 instead of the 70 I thought would be sufficient. I would presume the use of the AC system has a comparable effect to the loss of range in using the heating system in the 90 degree heat of FL.

 

[grichard]

I would presume the use of the AC system has a comparable effect to the loss of range in using the heating system in the 90 degree heat of FL.

Not at all! Using an A/C in "very hot" weather uses far less energy than the resistance heater in "very cold" weather. You won't see anything like the range drop of driving in icy cold.

 

[RockinWithKids]

I'm in Florida but after reading this thread, I'm so glad I ordered the 85 instead of the 70 I thought would be sufficient. I would presume the use of the AC system has a comparable effect to the loss of range in using the heating system in the 90 degree heat of FL.

My experience with my Leaf would indicate that AC is nothing like the battery consumption used to heat the car. There is a small hit with AC, but nothing like heat (especially in the dead of winter in MN).

We'll find out soon if I made the right decision because I acquired my 70D yesterday!

#PermaGrin
#IfDecisionWrongCanAlwaysRent

 

[chriSharek]

My experience with my Leaf would indicate that AC is nothing like the battery consumption used to heat the car. There is a small hit with AC, but nothing like heat (especially in the dead of winter in MN).

We'll find out soon if I made the right decision because I acquired my 70D yesterday!

Well, first congrats to you! I lose about 10% of my range using the AC in my Volt. I figured it would be about that or more with the MS. Again, in FL, using the heat is not as much of an issue - especially with the heated seats.

 

[3mp_kwh]

Updating the original questions...
1. What was the longest trip you've taken during winter in your 70D in temperatures that were below 40F?
2. What was your Wh/mile?
3. What was the temperature (approximately) during your driving?
4. Did you get the range you expected?

Not a 70kwh owner, but Wh/mile is so dynamic, especially starting with a cold battery, that I wanted to relate my "go by" when planning ~15F trips with an 85MS:
-For highway ~60-65mph, you lose ~2miles of rated range for every 1 mile driven, for the first 20 miles. Then it goes back down so fast, that it is hard to live by a single "Wh/mile" figure. I can get right on top of 1 mile, for 1 mile rated range, after those first 20 miles. Add a second cold soak into your range planning, and forget Wh/mile, or range. You are ultimately budgeting for the "warm-ups", which only then math-out the range you can expect.


A 2 X 75mi trip, starting cold both times, is totally different than 1 X 150. I can understand the questions trying to answer a single max range trip, but think they do a poor job addressing some common scenarios 70kwh owners will face.

 

[PA70D]

Longest trip this winter about 450 miles. Temperature range during the trip 35 high to 8 or 9 as a low. Only on the last leg when in single digits did I get concerned because it was late at night, in the mountains, and snowing significantly. Rerouted about ten miles outside of plan to super charger in Battlebough, VT.. Was driving NE on hwy 7 to Lebanon,NH trip meter stated 3% at destination. Normal plan for trip plan is to charge 150% between stops. This has always worked including this winter.

More recent trip might be a better reference. Take this trip often so can compare.
156 miles 22degrees F at start high teens at finish, charged to 100%, preheated about 20 minutes before start, weather windy but clear, some elevation change I78 east to I81. Average speed 70mph. Reached home at 6%.
Same trip between 60 & 70 degrees, usually travel at average speed closer to 75 mph reach home between 17 - 18%

at speed Wh/mile around 380, starting out around 490
Range was about as expected, did decrease speed slightly because the new firmware downloaded added a recommended speed to reach destination. Would not have otherwise and believe still would have been OK. Never went as low as the recommendation.
Don't think about range anymore as long as I have a charge to give me 150% rated mileage for the leg. The Lebanon leg in the storm above was at 148% of the charge left Albany, NY at so probably would have made it without a detour.

- - - Updated - - -

Longest trip this winter about 450 miles. Temperature range during the trip 35 high to 8 or 9 as a low. Only on the last leg when in single digits did I get concerned because it was late at night, in the mountains, and snowing significantly. Rerouted about ten miles outside of plan to super charger in Battlebough, VT.. Was driving NE on hwy 7 to Lebanon,NH trip meter stated 3% at destination. Normal plan for trip plan is to charge 150% between stops. This has always worked including this winter.

More recent trip might be a better reference. Take this trip often so can compare.
156 miles 22degrees F at start high teens at finish, charged to 100%, preheated about 20 minutes before start, weather windy but clear, some elevation change I78 east to I81. Average speed 70mph. Reached home at 6%.
Same trip between 60 & 70 degrees, usually travel at average speed closer to 75 mph reach home between 17 - 18%

at speed Wh/mile around 380, starting out around 490
Range was about as expected, did decrease speed slightly because the new firmware downloaded added a recommended speed to reach destination. Would not have otherwise and believe still would have been OK. Never went as low as the recommendation.
Don't think about range anymore as long as I have a charge to give me 150% rated mileage for the leg. The Lebanon leg in the storm above was at 148% of the charge left Albany, NY at so probably would have made it without a detour.

 

[CHGolferJim]

For limited interstate segments on 4 trips in Carolinas and Virginia in Dec/Jan:

70mph at 50*-60*F = ~115% rated/actual
70-75mph at 20*-28*F = ~135% rated/actual

Hope to improve cold weather efficiency by learning to use pre-heating and range mode better. I tend to drive 70mph when trying to stretch actual range, and 75-80 between close together superchargers and the last leg to home.

 

[Jtrader]

I've read a lot of scenarios but I'm new to this and don't understand all the acronyms and nuances so I'm simply wondering if a 70D with 19" wheels can go at least 200 actual miles at 70-75 mph in 50 degree weather with 2 adults, 2 suitcases and 2 golf bags.

 

[CHGolferJim]

I've read a lot of scenarios but I'm new to this and don't understand all the acronyms and nuances so I'm simply wondering if a 70D with 19" wheels can go at least 200 actual miles at 70-75 mph in 50 degree weather with 2 adults, 2 suitcases and 2 golf bags.

About 200, as several of my recent segments suggest (not sure it's proven yet). Might have to drop to 65mph.

 

[3mp_kwh]

I've read a lot of scenarios but I'm new to this and don't understand all the acronyms and nuances so I'm simply wondering if a 70D with 19" wheels can go at least 200 actual miles at 70-75 mph in 50 degree weather with 2 adults, 2 suitcases and 2 golf bags.

For somebody just coming to Tesla, I'd get as much range as you can afford for a general circumstance like 200 mile drives. If not, don't be disappointed at having to pull into a supercharger/CHAdeMO, for 5-10 minutes if on the way with a 70.

A reference is how 85kwh owners can rely on 200 miles, in pretty much all conditions (like today's blizzard). 15kwh is a lot of storage and $10k is a lot of money. If you were planning on a 70D, for regular drives like the one you referenced, I'd say pay up $5k and go to RWD 85 (+snows, if necessary).

 

[RockinWithKids]

Not a 70kwh owner, but Wh/mile is so dynamic, especially starting with a cold battery, that I wanted to relate my "go by" when planning ~15F trips with an 85MS:
-For highway ~60-65mph, you lose ~2miles of rated range for every 1 mile driven, for the first 20 miles. Then it goes back down so fast, that it is hard to live by a single "Wh/mile" figure. I can get right on top of 1 mile, for 1 mile rated range, after those first 20 miles. Add a second cold soak into your range planning, and forget Wh/mile, or range. You are ultimately budgeting for the "warm-ups", which only then math-out the range you can expect.


A 2 X 75mi trip, starting cold both times, is totally different than 1 X 150. I can understand the questions trying to answer a single max range trip, but think they do a poor job addressing some common scenarios 70kwh owners will face.

Very helpful... thanks.

The original intention of starting this thread was to try and understand what might be the worst expected range I might get on a road trip that would span multiple superchargers. Earlier up the thread I put in what those assumptions are. Over time I will be carefully looking at reality vs hypothesis and posting back to this thread.

 

[PA70D]

I have a 70D with 19” wheels (right now winter tires as well) and have done a number of 200 mile trips with comparable loads. Have never had a problem. This is our first year of driving an all-electric and have learned that when driving an all-electric your thought process over time becomes slightly different.

For example, if you are going on a long trip you only need to make it to the next super charger. You only charge to about 80% because it is fast and you move on.

If your destination is 200 miles and you are spending time, there you can charge overnight or for the time at your activity.

It has been my experience of using a rule of 150% charge for any trip. With this rule have never worried about speed (typical highway around 75 mph) or weather. With your scenario of a 200-mile trip, my plan would be a rout that would include a super charger or plan on staying at the speed limit from the start of the trip. The model S provides a range calculator when driving that is very helpful and with the latest update provides a recommended maximum speed to reach your destination.

There is a good blog on trips with a model “S” and other threads on this.
The Rules of Model S Road Tripping - Blogs - Tesla Motors Club - Enthusiasts & Owners Forum