Winter Cold Battery Efficiency

Puppethead said:
Just throwing this out here, I don't think conditions will get more extreme than this. I actually saw -35 ºF after I took these photos.

I still could get 80 miles in Green+ on that day,
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Wow! That is cold driving. You went Green+ when it was -31F? Doesn't that disable your heater?
 
GvilleGuy said:
Wow! That is cold driving. You went Green+ when it was -31F? Doesn't that disable your heater?
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I was just coming in to ask this.

I am sidelined with snow at the moment myself so missing some really cold temps. Hopefully this is the last snow of the season.
 
No no, I was in Green (as shown in the photos). I would have had 80 miles range in Green+, but I didn't drive like that. Although that kind of temperature isn't too unbearable with the right winter clothing, and no wind.
 
Puppethead said:
No no, I was in Green (as shown in the photos). I would have had 80 miles range in Green+, but I didn't drive like that. Although that kind of temperature isn't too unbearable with the right winter clothing, and no wind.
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Thanks to everyone on this forum for their comments and data. I was never concerned about the drop in range when we were below freezing but she was not too happy when we pulled into our driveway from an 85 mile trip with 9 miles left. Ran in green mode the whole time with the heat and wipers on and at 60 mph in 30F rainy weather.
Worst part of the trip was a 3 mile run up a mountain that took 10 miles off the guess-o-meter. I knew it would happen but she didn’t. I experienced, vicariously, lots of range anxiety.[emoji3]


Sent from my iPhone using Inside EVs
 
I've only had my mini for a week. Last night I was driving in:
- green mode
- wiith factory cross bars
- climate control set at AUTO with AC on at 68F with heated steering wheel on
- 20 miles trip with 10% city (25-35 mph) and 90% highway (55 mph)
- 28F outside temperature

It shows 3.6 mile/kWh. Does it look right?
 
sacharama said:
I've only had my mini for a week. Last night I was driving in:
- green mode
- wiith factory cross bars
- climate control set at AUTO with AC on at 68F with heated steering wheel on
- 20 miles trip with 10% city (25-35 mph) and 90% highway (55 mph)
- 28F outside temperature

It shows 3.6 mile/kWh. Does it look right?
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In Jessie's experience, 3.0 to 5.0 represents about three standard deviations of SE efficiencies.
 
sacharama said:
I've only had my mini for a week. Last night I was driving in:
- green mode
- wiith factory cross bars
- climate control set at AUTO with AC on at 68F with heated steering wheel on
- 20 miles trip with 10% city (25-35 mph) and 90% highway (55 mph)
- 28F outside temperature

It shows 3.6 mile/kWh. Does it look right?
Click to expand...
Yes that looks right. It's about 3.3mi/kWh in 32F and 2.6mi/kWh in 0F weather. The lowest I've ever seen is probably 1.9-2.0mi/kWh in -40F. Much of the efficiency drops with cabin comforts (heated steering wheel, heated seats, backup resistance heater, etc.). If you can precondition before departure, there is probably a 5-10% efficiency gain for not using the heated steering wheel/seats.

In the summer, I'm usually in the 5.0-5.2mi/kWh efficiency.
 
teslarati97 said:
Yes that looks right. It's about 3.3mi/kWh in 32F and 2.6mi/kWh in 0F weather. The lowest I've ever seen is probably 1.9-2.0mi/kWh in -40F. Much of the efficiency drops with cabin comforts (heated steering wheel, heated seats, backup resistance heater, etc.). If you can precondition before departure, there is probably a 5-10% efficiency gain for not using the heated steering wheel/seats.

In the summer, I'm usually in the 5.0-5.2mi/kWh efficiency.
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Thanks!

If the car is parked outdoor without the charger connected, would preconditioning make sense?

As it would consume the battery to heat up the cabin, hence there will be no gain. Do I understand that correctly?
 
sacharama said:
If the car is parked outdoor without the charger connected, would preconditioning make sense?

As it would consume the battery to heat up the cabin, hence there will be no gain. Do I understand that correctly?
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You are correct, my experience is climatization will use as much as 5% SoC and only marginally warm the batteries. I decided it's better to just drive, unless the warm cabin is really desired at departure.

(Technically it's climatization for the SE, since it won't directly heat the batteries like true conditioning. The only "conditioning" comes from charging or driving.)

I have to park outside all day without a charge, and here's my winter strategy for my 85+ mile daily commute:
  • Delayed charging and climatization before I leave in the morning, so batteries are at normal operating temperature and I don't use any range heating the car.
  • Park in the sun whenever possible, letting solar radiation heat the metal car body and hopefully warm the batteries.
  • Do a mid-day charge for about half an hour. I go to a nearby charger over lunch.
 
Preconditioning (sorry climatization) generally runs the heat pump to a fixed temperature for heating (or cooling). With an EVSE plugged in, it will help top off the HV battery when necessary (still runs off of the battery).

In milder climates the gain is because you might run the preconditioning for 3-5 minutes using the heat pump compared to 20-30 minutes of heated steering wheel + heated seats for the entire trip. Yes the heat pump still runs during the trip, but the efficiency is still better compared to resistance heating.
 
[bump]
Hoping some folks can share their experiences with the recent once-in-a-generation deep freeze across much of the country.
I'm particularly curious about DC fast charging at extreme cold temperatures.
 
fishbert said:
[bump]
Hoping some folks can share their experiences with the recent once-in-a-generation deep freeze across much of the country.
I'm particularly curious about DC fast charging at extreme cold temperatures.
Click to expand...
Generally the cold capped 350kW chargers at 40-45kW at -11F so I think the only thing you have to worry about is a cold battery.
 
Kyle later tweeted this clarification:
@itskyleconner said:
Just a reminder the only problems in cold weather with DCFC we are seeing are with the new EA BTC units.

The SK Signet versions (identical other than the nameplate on the side) seem to work fine in the cold. However they are massively failing for other reasons (software?)
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US Dept of Energy says 1 kWh electricity is about 0.031 gallons of gas equivalent so 3 kWh is 0.093 gal so that would make it about 6.37 times more fuel used (guessing regular but it's not that much different for premium).
 
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