Cold weather range and battery temperature

[LL75]

Yes. Preconditioning is coming s00n, gone will go the days of us doing math to manually determine start times for warming our batteries.



Where's the fire, my dude? Can you slow down to 70? 80mph will do more damage than the cold will.

Driving 70 on the highway in Texas will get you the side eyes !!! I think i got enough of those at home from the wife. haha

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[tzoelt]

Yeah,my first winter with R1T in South Dakota going regularly to Minneapolis(233mi). Couldn’t make it home in “conserve” at 73 mph, w slight headwind Last 60 miles. Temp at start 22 deg. 35 at end of 3-1/2 hr trip. Can’t wait till Next week—highs in single digits, new AT wheels and tires and needing snow mode some of the time. Only one fast charger 60 miles from home?

 

[Riviot]

Yeah,my first winter with R1T in South Dakota going regularly to Minneapolis(233mi). Couldn’t make it home in “conserve” at 73 mph, w slight headwind Last 60 miles. Temp at start 22 deg. 35 at end of 3-1/2 hr trip. Can’t wait till Next week—highs in single digits, new AT wheels and tires and needing snow mode some of the time. Only one fast charger 60 miles from home?

Get the battery nice and warm, 90s, and keep it warm while driving through fast charging! No extended Cracker Barrel stops and you'll be fine. I did sub zero road trip and battery temp made all the difference.

 

[usulio]

Using 16lbs per kwh for battery and thermal capacity of 950 J/kg*K for a temperature rise of about 32F (20C) ideally would use about 4% of the battery capacity. I'd say your usage was about right.

Yep, my back of the envelope is similar. Also, physically raising a 7500lb vehicle 1400ft takes roughly 4 kWh of energy.

So jimk used roughly 9 kWh or 7% of the battery to fight physics (assuming 128 kWh usable) and roughly 16% of the battery to drive 33 miles in 20 degree F weather, an efficiency of around 1.6 miles/kWh which isn't great but sounds right to me considering all the other heating needed.

And as long as the battery needs to heat to 60, there is no heat pump or any other technology that can fix that 7% usage by physics. The only answers are preconditioning, and next time go somewhere that's downhill from you.

 

[RealBillNye]

With 20" snow tires, a ski rack, and 40 degree ambient temps, my max range is 212 miles, BTW. The car really needs a heat pump.

Have you checked your tire pressures at low temperatures? On a road trip with a warm battery I consistently get at least 275 miles of range even at 20F.

 

[NineElectrics]

Have you checked your tire pressures at low temperatures? On a road trip with a warm battery I consistently get at least 275 miles of range even at 20F.

My winter tires warm up to be about 54 PSI. The Nokian LT3 tires that I'm using combined with the 20" R600 wheels are probably not great for efficiency, nor is the ski rack.

Are you on 21" or 22" rims? 275 would be very impressive for 20" wheels, even in the summer.

 

[RealBillNye]

My winter tires warm up to be about 54 PSI. The Nokian LT3 tires that I'm using combined with the 20" R600 wheels are probably not great for efficiency, nor is the ski rack.

Are you on 21" or 22" rims? 275 would be very impressive for 20" wheels, even in the summer.

I'm on the 20" wheels with stock tires. In the summer on a road trip it is not difficult for me to get above 300 miles of range in conserve mode. Round trip from Hood River to Bend, OR I got up to 350 miles on a charge before they increased the usable capacity. Granted the speed limits on that route are 55-60 the whole way which did help.

 

[DaveA]

Thanks all for the good info. I will charge up to 90% the night before and then switch up to 100% in the morning before leaving so the battery is warmed up. The battery temp has usually been 55-60 in the garage.

My R1S is on 20" ATs. I plan to charge to 100% before leaving the house. I'm driving ~300 miles in temps between 40 (low)-60 (high), on flat roads. Once I get on the highway I plan to use conserve mode. That will probably give me ~300 mile range. I will most probably be driving 75-80mph so, I'm planning on 250 mile range and leaving a little buffer to charge at the 200 mile mark.

68 mph will get you 310 easy if you don't have wind....in my experience. Conserve and low setting and 6 coats of wax.

 

[NineElectrics]

I'm on the 20" wheels with stock tires. In the summer on a road trip it is not difficult for me to get above 300 miles of range in conserve mode. Round trip from Hood River to Bend, OR I got up to 350 miles on a charge before they increased the usable capacity. Granted the speed limits on that route are 55-60 the whole way which did help.

Most of that trip is also above 2,000 feet, which means 20% less dense air, which probably helps significantly. Congrats, though, those are great numbers.

I don't use conserve mode unless I have to due to concerns about tire wear.

 

[Franksmartin]

27 F is a really cold battery. Your range will improve if you charge for a few hours before you leave, which should get the battery in the 55-65 degree range. The new preconditioning in the next update should help even more assuming it get the battery above 70 which is optimal.

 

[HimuraMOdo]

Yep, my back of the envelope is similar. Also, physically raising a 7500lb vehicle 1400ft takes roughly 4 kWh of energy.

So jimk used roughly 9 kWh or 7% of the battery to fight physics (assuming 128 kWh usable) and roughly 16% of the battery to drive 33 miles in 20 degree F weather, an efficiency of around 1.6 miles/kWh which isn't great but sounds right to me considering all the other heating needed.

And as long as the battery needs to heat to 60, there is no heat pump or any other technology that can fix that 7% usage by physics. The only answers are preconditioning, and next time go somewhere that's downhill from you.

The 16% usage from ABRP already has the elevation gain taken into account.
So the rest of 7% is for battery preconditioning and cabin heating, well also assuming tire pressure etc are at nominal conditions.

 

[RivRyan]

Using seat heat instead of cabin heat to the degree you can makes a big difference as well.

 

[YellowR1T]

I think I read that the next update is going to allow for preconditioning of the battery and temps while plugged in for planned trips (Tesla already does this). That should help you out quite a bit.

Is the 0.5 update out yet? I am still on 0.46

 

[jjswan33]

So quick math is 30% of battery to go 66 miles which is 66/95=69.5% which isn't as horrible.

A little more math 32% of the battery means about 41kWh. Assuming the 66 miles that equates to ~1.6mi/kWh. OP didn't mention the tires he was using but that doesn't sound bad to me when you consider the elevation change and temps.

 

[RealBillNye]

Most of that trip is also above 2,000 feet, which means 20% less dense air, which probably helps significantly. Congrats, though, those are great numbers.

I don't use conserve mode unless I have to due to concerns about tire wear.

Tire wear isn't a problem as long as you rotate your tires every 6k miles. Go for it. Conserve mode makes a big difference in range.

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