Subzero Fahrenheit Road Trip Data

[crazybrit]

• Dates
  • December 29, 2013 to December 30, 2013
• Car
  • P85
  • VIN: 05619
  • Odometer: 6325 miles (10,179km)
  • 19in All Seasons (factory)
  • Unmodified (original) window vents
  • Tech Pack
  • Pano Roof
  • NO winter package (was not available)
  • Other unrelated options
• Trip Details
  • Origin: Burnsville, MN 55306
  • Destination: Granite Falls MN
  • 35W North, 494 West, 212 West
  • Round trip, with overnight at Prairie’s Edge Casino
  • Distance 131.5 miles (211.6 km) each way
• Preparations:
  • Trickle Charged to Range Charge (11 amps @ 240v) to coincide with completion one hour prior to departure
  • Vehicle in Range Mode
  • Power Saving ON
  • Set tire pressures to 47psi (3.24 bar) in the garage (ambient 37F/2.8C)
  • Preheated Cabin to setpoint of 65F (18.3C)
• Payload
  • 4 Adults, 600lbs total weight (272kg)
  • Luggage 100lbs (45kg)
• Outbound Leg
  • Departure Conditions
    • Garage 42F (5.6C)
    • Outside air -2F (-18.9C)
  • Prevailing Conditions
    • Outside Temp -5F (-20.5C)
    • Heading West, with NW wind of 15mph (24 km/h)
    • Full Sun
  • Speed set to 55mph (88.5 km/h)
  • HVAC
    • 65F (18.3C) Setpoint
    • All three vent groups on
    • Fan at 8
    • Side vents pointed outwards (to windows)
    • Minimal fogging
    • Light coats, no gloves or scarfs
  • Power Consumed
    • 56.3kWh
  • Initial Rated Miles (km)
    • 261 (420)
  • Final Rated Miles (km)
    • 58 (93)
  • Average: 428 Wh/mile (266 Wh/km)
• Overnight Conditions
  • -15F (-26C) low
• Charging
  • 14-50 (50amp/ 240v)
  • RV Park adjacent to Casino with full service hookup
  • Very helpful staff
  • Plowed a spot for me
  • Charged to 90% on arrival
  • Charged final 10% in the morning
  • Took 3hrs (chart below)
  • ​Preheated Cabin (took 1hr to get to 48F/8.9C)
• Return Leg
  • Departure Conditions
    • Outside air -2F (-18.9C)
  • Prevailing Conditions
    • Outside Temp -1F (-18.3C)
    • Heading East, with SE wind of 10mph (16 km/h)
    • Full cloud with light snow
    • Slick spots
  • Speed set to 55mph (88.5 km/h)
  • HVAC
    • 65F (18.3C) Setpoint
    • All three vent groups on
    • Fan at 8
    • Side vents pointed outwards (to windows)
    • Minimal fogging
    • Light coats, no gloves or scarfs
  • Power Consumed
    • 56kWh
  • Initial Rated Miles (km)
    • 260 (418)
  • Final Rated Miles (km)
    • 55 (88.5)
  • Average: 427 Wh/mile (265 Wh/km)

Note: on the return leg, the headwind dropped, and I increased speed to keep the same burn-rate. Was able to get up to 65mph (105km/h)

Photos and Charts below



- - - Updated - - -

Charging Location

Return trip conditions:

Point at which I got full regen on return trip:

 

[AmpedUP]

Summary: Speed makes ALL the difference.

 

[crazybrit]

Charge Rate for the last 10% after overnight cold soak. Cabin Temp was reading -2F (18.8C) at the start (iPhone app). Charging began 30 minutes after initiation. Outside air temp was -5F (-20.5C) after an overnight low of approx -15F (-26C). Interior temp warmed to 4F (-15.5C) towards the end of the charging (before turning on the HVAC). Graph is rated miles vs time

 

[montgom626]

Brrrrrrrrrrrrrrrrrrrrrrrrrrrrrr!

 

[efusco]

I work nights a few days a month and have the ability to trickle charge on 120v while at work. What I try to do is turn on the heat in the car to ~72 F a couple of times during the course of the night shift to keep the battery temp, and cabin temp, up a bit. I have found, like you did, that if you allow the full cold soak of the battery and cabin that it takes a LONG time to warm that huge cold thermal mass from a very low ambient temp.

In your particular case I might have charged to around 70% @40 amps, then turned down the amperage to 10 or so so that there would be a continuous charge throughout the night, then crank it back up to 40 amps, if necessary, to get to the max range charge. It's a lot of futzing around, I realize, but I do think it helps with that take-off efficiency.

One other thing, as long as you're on shore power, might as well warm the cabin to 72F or so, then once everyone's loaded up and you disconnect from shore power you can turn it down to 65F and you'll reduce the work of the heating system a little bit for a little while.

 

[Zythryn]

Awesome write up!
Many thanks.

 

[crazybrit]

Efusco: Thanks for the good suggestions.

I would have played with the current a little more, but unfortunately the iPhone app doesn't have that flexibility, and the car was not close to my hotel room. Even a short walk in -10F can burn my ears off! I know there is the TeslaTap app, but I am a little concerned with the security of it (unencrypted passwords: Has this been fixed?). Also, I was playing the risk game. In an unfamiliar place, I wasn't sure of the reliability of the infrastructure, so I wanted to get a 90% charge in as quickly as possible to ensure I had enough power to limp home if things went bad on me.

I did think of running the heat in the night to try to prevent some of the cold soak, but I didn't. I wasn't sure if (a) it would help, and（b) if there would be some unintended consequences. Moreover, I was fast asleep when the temp would have dipped to its lowest level (3 or 4am)!

If I had waited to heat the cabin to 72F before disconnecting shore power, we would have been there another hour or so. We were concerned about the snowstorm moving in, so made the call to leave. For me, a setpoint of 65 gets me a cabin temp of 72 once it is done. We were all very surprised at how comfortable the cabin felt when we got in. I guess when you are at -2F, 50 feels pretty good!

Security shuttled me to the campground, and they only had a pickup with one passenger seat, so I had to go and disconnect the car from shore power, and drive it back to the hotel to pickup my passengers. I had it setup so that all the remaining luggage would go in the frunk, that way we could load up before opening any of the cabin doors (another benefit of the frunk!). We then counted to three, and all jumped in the car together. Anyone watching would have laughed at the ballet! It is all so much easier when we leave from a warm garage. However, as it turned-out, the cold-soaked start really didn't add much of a penalty when you compare the outbound and return numbers. Surprising.

Many things were not ideal, but in a way I was glad to test out a worst case scenario to get some data. I was very impressed with the way the car behaved. Amazing actually.

I work nights a few days a month and have the ability to trickle charge on 120v while at work. What I try to do is turn on the heat in the car to ~72 F a couple of times during the course of the night shift to keep the battery temp, and cabin temp, up a bit. I have found, like you did, that if you allow the full cold soak of the battery and cabin that it takes a LONG time to warm that huge cold thermal mass from a very low ambient temp.

In your particular case I might have charged to around 70% @40 amps, then turned down the amperage to 10 or so so that there would be a continuous charge throughout the night, then crank it back up to 40 amps, if necessary, to get to the max range charge. It's a lot of futzing around, I realize, but I do think it helps with that take-off efficiency.

One other thing, as long as you're on shore power, might as well warm the cabin to 72F or so, then once everyone's loaded up and you disconnect from shore power you can turn it down to 65F and you'll reduce the work of the heating system a little bit for a little while.

- - - Updated - - -

Summary: Speed makes ALL the difference.

Yes air speed, not ground speed. I wish the car had a pitot tube in the cone, to give us air speed readout.

 

[rjcbox]

great details, appreciate the write up. my one thought was why not heat the cabin to 85F in your garage and again after overnight stay, while still plugged in. this will give you/passengers some extra heat energy from the car's interior thermal mass. recently read of an owner doing this in very cold temps and being very comfortable, not having to turn on heat until 15-20min into drive - all while reserving full range. again, great trip report, thanks

 

[J in MN]

Very nice. You did slightly better than I expected.

 

[crazybrit]

great details, appreciate the write up. my one thought was why not heat the cabin to 85F in your garage and again after overnight stay, while still plugged in. this will give you/passengers some extra heat energy from the car's interior thermal mass. recently read of an owner doing this in very cold temps and being very comfortable, not having to turn on heat until 15-20min into drive - all while reserving full range. again, great trip report, thanks

Outgoing: unfortunately my wife gets very uncomfortable when the cabin is too hot. A setpoint of 65 gets me a cabin temp of 72. It was very comfortable

Return: take a look at my response to Efusco above.

Thanks!

 

[Kalud]

Great details! One thing to note is that turning off range mode (hvac) and then pre-heating the cabin (during the night while on shore power) would have heated the battery pack. Leaving on range mode off only heats the cabin. Key,as said earlier, is to charge more before departure thus lowering charging current initially, but its much more complicated and not practical. Easiest I found is turn hvac range mode off, and pre-head the cabin longer before departure (heats battery too).

 

[crazybrit]

Great details! One thing to note is that turning off range mode (hvac) and then pre-heating the cabin (during the night while on shore power) would have heated the battery pack. Leaving on range mode off only heats the cabin. Key,as said earlier, is to charge more before departure thus lowering charging current initially, but its much more complicated and not practical. Easiest I found is turn hvac range mode off, and pre-head the cabin longer before departure (heats battery too).

Are you saying that Range Mode affects cabin heating when on Shore Power? Wow, that doesn't make much sense. It does explain why it took so long to get to temp though. Why would they do that? Range mode should take everything it can from Shore Power, not limit that too.

 

[Kalud]

Are you saying that Range Mode affects cabin heating when on Shore Power? Wow, that doesn't make much sense. It does explain why it took so long to get to temp though. Why would they do that? Range mode should take everything it can from Shore Power, not limit that too.

No, its battery heating that is disabled on shore power when Range Mode is enabled.

 

[Vger]

Very impressive benchmark accomplishment and great documentation. Thanks!!

 

[efusco]

No, its battery heating that is disabled on shore power when Range Mode is enabled.

Really? Why would that be...how would that be of benefit to Range? Is this documented or an observation and how was it determined? I have always used Range Mode, couldn't see a reason to turn it off, but if it impacts battery conditioning when I'm plugged in that would change my behavior in very hot and very cold weather.

 

[Kalud]

Really? Why would that be...how would that be of benefit to Range? Is this documented or an observation and how was it determined? I have always used Range Mode, couldn't see a reason to turn it off, but if it impacts battery conditioning when I'm plugged in that would change my behavior in very hot and very cold weather.

I saw it numerous time on the forum and its what I observe on my end so far (car is 1 month old only). I have a heated garage so I only see that on road trip in the cold, when charging outside. I don't see any benefits to it, only drawback.

See this thread for source: http://www.teslamotorsclub.com/showthread.php/23505-Delay-in-Battery-Heating-message

 

[efusco]

I saw it numerous time on the forum and its what I observe on my end so far (car is 1 month old only). I have a heated garage so I only see that on road trip in the cold, when charging outside. I don't see any benefits to it, only drawback.

See this thread for source: http://www.teslamotorsclub.com/showthread.php/23505-Delay-in-Battery-Heating-message

Thanks, interesting. Now I have to consider turning Range mode off when I'm plugged in, and back on when driving...what a pain.

 

[jerry33]

No, its battery heating that is disabled on shore power when Range Mode is enabled.

Mine doesn't behave that way. True the battery doesn't heat up as fast, but it does heat up. There is a significant difference in where the limit bars are between preheating vs. no preheating.

 

[Raven]

Mine doesn't behave that way. True the battery doesn't heat up as fast, but it does heat up. There is a significant difference in where the limit bars are between preheating vs. no preheating.

I believe jerry33 is right. It's still heating, just at a reduced rate. Everything is done at a reduced rate on range mode.

 

[crazybrit]

My battery was heated on shore power. No doubt about it. I had no power limit when I left, only regen limit, which did stick around for a while. At that temp, with no battery heating, I would have had a power limit for sure.

I believe jerry33 is right. It's still heating, just at a reduced rate. Everything is done at a reduced rate on range mode.

- - - Updated - - -

Thank you!

Very impressive benchmark accomplishment and great documentation. Thanks!!