Winter Cold Battery Efficiency

Wow! That is cold driving. You went Green+ when it was -31F? Doesn't that disable your heater?

 

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.

 

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.


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Indeed! If you want to know what the word means : https://en.wikipedia.org/wiki/Hakkapeliitta

 

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?

 

In Jessie's experience, 3.0 to 5.0 represents about three standard deviations of SE efficiencies.

 

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.

 

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?

 

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.

 

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.

 

Check out the recent Out Of Spec Reviews video where Kyle reports that none, zero, zilch, of the new model Electrify America chargers worked in the recent cold front.


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recent Out Of Spec Reviews video where Kyle reports that none, zero, zilch, of the new model Electrify America chargers worked in the recent cold front.

 

4th generation EA chargers seem to work in Michigan on an EV6. Well one station was down but the others were still up. I think it was 0F and -20F with windchill.

 

Kyle later tweeted this clarification:

 

Did you see the TFLEV cold weather 3 hour idling test SE vs R56 GP3?

 

I used my car in a parade. It took about 2.5 hours warm weather with no heat on - and I was pleasantly surprised it used only about 2%

 

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).