59 Months (and counting) of EV driving...

[SpaceEVDriver]

For me, the only consideration for minor range loss is whether or not you might need any extra buffer when traveling long distances, and perhaps planning a charging stop accordingly.

Couple of points (that were already made above): The vehicle S/W accounts for this with displayed range estimates (it's not scary or unknown what your range will be, based on SOC in the winter). The vehicle's S/W also makes it very easy to route to a charger, in the event that you are on a road trip and need to add a charging stop.

If you are simply doing daily driving, there's nothing to worry about, since a 20% hit won't even impact you with an adequate SOC.

One of the bigger benefits of cold weather driving in an EV is how quickly you can precondition your cabin and warm the vehicle. It's nearly instantaneous when compared to warming up the cabin in an ICE vehicle. So, at the end of the day, I see no reason for anyone to think cold is a scary scenario, and I have never had any problems in cold conditions in the backcountry or skiing for example.

Very much all of this.

Disclaimer: We don’t get the very, very cold here. The lowest I’ve seen on my weather station was -15 F, but that was an anomaly. Generally in the winter we get below freezing, but not much below: not lower than a daytime low of about 5 F once or twice a season.

I’ve never even worried about the cold for around town driving. It’s simply not an issue.

For road trips, we’ve seen lower efficiency (down to about 2.0 miles/kWh, or about 260 miles range in the Sierra Nevadas in winter). But that’s never been a scary cause for concern.

 

[J Alynn]

Do you mean my range calculation is more than the range estimate on the screen?

Early on Ford was optimistic with range and some people felt it was misleading. So Ford adjusted their algorithm to be more pessimistic. I agree with their decision—you don’t want people to believe the range estimate but fall short because of an unexpected change in temperature, speed, elevation change, etc. So you give them a pessimistic range estimate.

That, of course, gives them a different reason to be upset (“I’m not getting the range I was told I would get in the EPA estimates.”)

It feels like you just can’t make some people understand it’s just an estimate.

Yeah-that’s what I was suggesting and to your point-people are never happy. I was just surprised that based on your experience 2.5 miles per kWh that it was 30%. I would’ve guessed 10-15% so glad your math shows a solid safety net which is what I’d prefer to see anyway.

 

[Logan]

Very much all of this.

Disclaimer: We don’t get the very, very cold here. The lowest I’ve seen on my weather station was -15 F, but that was an anomaly. Generally in the winter we get below freezing, but not much below: not lower than a daytime low of about 5 F once or twice a season.

I’ve never even worried about the cold for around town driving. It’s simply not an issue.

For road trips, we’ve seen lower efficiency (down to about 2.0 miles/kWh, or about 260 miles range in the Sierra Nevadas in winter). But that’s never been a scary cause for concern.

What about parking/leaving overnight without charging in the cold?

IE, the "going to do an overnight snow-shoeing trip up the mountain an hour or few from home" sort of scenario. Where the car is left at ~0f overnight.

Does the BMS try to keep the battery above a certain temp overnight, thus draining some of the battery? Or any other weird situations?

We have even milder winters around here, and we haven't even hit our "cold" time of the year yet, so I haven't had the chance to test anything. But even so, I expect no problems as we have a garage, and have the vehicle plugged in a lot.

But the times when the vehicle is allowed to cold soak up in the mountains, without charging, is a totally different scenario. And I'm not sure how it will handle those, so curious if you have any insight there.

 

[Jasco]

What about parking/leaving overnight without charging in the cold?

IE, the "going to do an overnight snow-shoeing trip up the mountain an hour or few from home" sort of scenario. Where the car is left at ~0f overnight.

Does the BMS try to keep the battery above a certain temp overnight, thus draining some of the battery? Or any other weird situations?

We have even milder winters around here, and we haven't even hit our "cold" time of the year yet, so I haven't had the chance to test anything. But even so, I expect no problems as we have a garage, and have the vehicle plugged in a lot.

But the times when the vehicle is allowed to cold soak up in the mountains, without charging, is a totally different scenario. And I'm not sure how it will handle those, so curious if you have any insight there.

It has been a while since I have measured overnight drain in cold temperatures but I recall losing about 1-2% a night in freezing temperatures assuming no other loads are on the battery such as sentry mode being enabled or me constantly checking the battery level through the app. I'm sure this varies by vehicle. You will be much less efficient in the morning when driving away though unless you precondition which itself uses a bit of energy. So overall not a big concern unless your battery is left at an extremely low SOC which is not good in super cold temperatures.

Also, overnight snow shoeing trips are great fun!

 

[Logan]

It has been a while since I have measured overnight drain in cold temperatures but I recall losing about 1-2% a night in freezing temperatures assuming no other loads are on the battery such as sentry mode being enabled or me constantly checking the battery level through the app. I'm sure this varies by vehicle. You will be much less efficient in the morning when driving away though unless you precondition which itself uses a bit of energy. So overall not a big concern unless your battery is left at an extremely low SOC which is not good in super cold temperatures.

Also, overnight snow shoeing trips are great fun!

Ah, ok, so it does actually draw from the battery to keep itself from freezing solid. But maybe not that much of a worry, in terms of percentage?

Also, in this scenario, I'm coming down the mountain, and losing a few thousand ft of elevation. So I imagine that regen will do quite a bit to warm up the battery/motors.

And, yes, overnight snowcampouts are great fun .

I mentor a group of 15-18yr old boys, and we do a yearly winter snowshoe hike. And... this is what we did last year. Snowjabba . He was a solid 5ft tall. So pretty good size.

Figured people would like this photo as well. The ZJ that I've had for almost 20yrs now. Not stuck, just parking.

And my hammock setup.

 

[cyure]

Ah, ok, so it does actually draw from the battery to keep itself from freezing solid. But maybe not that much of a worry, in terms of percentage?

Also, in this scenario, I'm coming down the mountain, and losing a few thousand ft of elevation. So I imagine that regen will do quite a bit to warm up the battery/motors.

And, yes, overnight snowcampouts are great fun .

I mentor a group of 15-18yr old boys, and we do a yearly winter snowshoe hike. And... this is what we did last year. Snowjabba . He was a solid 5ft tall. So pretty good size.

View attachment 11278
Figured people would like this photo as well. The ZJ that I've had for almost 20yrs now. Not stuck, just parking.
View attachment 11279

And my hammock setup.

View attachment 11280

You lost me at look at my hammock in the snow. I remember when my son was in Scouts he got his penguin patch for sleeping in the snow. . No thanks. Glamping. I’m all for glamping.

 

[SpaceEVDriver]

What about parking/leaving overnight without charging in the cold?

IE, the "going to do an overnight snow-shoeing trip up the mountain an hour or few from home" sort of scenario. Where the car is left at ~0f overnight.

Does the BMS try to keep the battery above a certain temp overnight, thus draining some of the battery? Or any other weird situations?

We have even milder winters around here, and we haven't even hit our "cold" time of the year yet, so I haven't had the chance to test anything. But even so, I expect no problems as we have a garage, and have the vehicle plugged in a lot.

But the times when the vehicle is allowed to cold soak up in the mountains, without charging, is a totally different scenario. And I'm not sure how it will handle those, so curious if you have any insight there.

It has been a while since I have measured overnight drain in cold temperatures but I recall losing about 1-2% a night in freezing temperatures assuming no other loads are on the battery such as sentry mode being enabled or me constantly checking the battery level through the app. I'm sure this varies by vehicle. You will be much less efficient in the morning when driving away though unless you precondition which itself uses a bit of energy. So overall not a big concern unless your battery is left at an extremely low SOC which is not good in super cold temperatures.

Also, overnight snow shoeing trips are great fun!

I haven’t noticed much loss either.

However, in a cold-soaked battery, the range can be reduced substantially even if the state of charge indicates the same as before cold soaking. This is because the state of charge is measured by watching what goes in vs what goes out. And the actual usable chemistry in the battery is dependent on temperature.

Imagine a 90% full bucket of water that you set outside on a very cold night.
As the bucket starts to freeze, there’s less liquid water available to you to pour out of the bucket. Even though the mass of water in the bucket is the same, the available amount of liquid water decreases while the water freezes.
Eventually, the top might mostly freeze, and there’s a convoluted path for the remaining liquid water to escape the bucket if you try to pour the water out. It will be quite difficult to get much liquid out of the bucket once it’s mostly frozen over—been cold soaked.

That’s analogous to what’s happening as the battery gets colder and colder. The available chemistry decreases because of the lower temperatures, even though the “charge” of the battery as tracked by the battery management module should be about the same.

In addition, with LFP batteries, the battery management module MUST maintain every cell's temperature above freezing or it won’t be able to charge that cell until it’s warmed it up. So good battery management systems will use some of their battery's own energy to keep the battery above freezing. This will not only use battery charge, but because the battery is relatively cold, its usable energy will be decreased as well. The system will not allow the battery cells to be charged if they’re too cold. It’s a major safety issue.

If you don’t have a place to plug in or keep the vehicle warm and you know it’s going to get very cold, you may run into unexpected range issues. This is true of all vehicles located where it gets very cold. If I’m going somewhere that’s very, very cold overnight and there’s no place to plug in, I’ll bring my auxiliary battery and plug into that. It will help keep the battery warm without drawing the main vehicle battery down too much.

 

[Logan]

If you don’t have a place to plug in or keep the vehicle warm and you know it’s going to get very cold, you may run into unexpected range issues. This is true of all vehicles located where it gets very cold. If I’m going somewhere that’s very, very cold overnight and there’s no place to plug in, I’ll bring my auxiliary battery and plug into that. It will help keep the battery warm without drawing the main vehicle battery down too much.

This was my exact worry.

I wonder if the harvester would ever fire up in those situations, for both warming, and charging. Even if you aren't around.

I do worry though. As at most of these trailheads I wouldn't just leave a battery bank plugged into the vehicle, as it could wander off if not secured.

 

[SpaceEVDriver]

This was my exact worry.

I wonder if the harvester would ever fire up in those situations, for both warming, and charging. Even if you aren't around.

I hope it will not. Firing up while enclosed in a home's garage would be a disastrous decision and could easily kill an entire family in their sleep.

I do worry though. As at most of these trailheads I wouldn't just leave a battery bank plugged into the vehicle, as it could wander off if not secured.

I have mine in the bed of the truck under the tonneau or in the bed cap with just the charging cable running through a small portal. I generally don’t worry about theft, though. It’s less mental and emotional load to deal with the theft once, if it ever happens, rather than worry about it every time I drive the truck.

 

[Logan]

I hope it will not. Firing up while enclosed in a home's garage would be a disastrous decision and could easily kill an entire family in their sleep.


I have mine in the bed of the truck under the tonneau or in the bed cap with just the charging cable running through a small portal. I generally don’t worry about theft, though. It’s less mental and emotional load to deal with the theft once, if it ever happens, rather than worry about it every time I drive the truck.

Ha, yes, obviously indoors would be bad.

But parked at a trailhead, maybe not. I believe this was something that has been discussed before (although usually under the topic of home backup power). With all the cameras, and sensors, this seems doable. I'd also say just making it a manual option would work (ie, I decide when I want this feature to be possible to be used or not), but that seems risky.

For the Terra, I can see how keeping the battery bank in the bed under cover/tonneau would likely work well. I'm reserved for a Traveler, hence the "not sure I just want to just leave this cooler sized thing on the ground next to the vehicle".

Is NMC better under cold temps than LFP?

 

[SpaceEVDriver]

Ha, yes, obviously indoors would be bad.

But parked at a trailhead, maybe not. I believe this was something that has been discussed before (although usually under the topic of home backup power). With all the cameras, and sensors, this seems doable. I'd also say just making it a manual option would work (ie, I decide when I want this feature to be possible to be used or not), but that seems risky.

Yeah, I can think of myriad ways for any kind of automated or manual option to fail. But at least a manual option, that reset every time the vehicle is restarted, might place the responsibility on a human taking a positive action to engage the engine rather than a piece of software or a company.

For the Terra, I can see how keeping the battery bank in the bed under cover/tonneau would likely work well. I'm reserved for a Traveler, hence the "not sure I just want to just leave this cooler sized thing on the ground next to the vehicle".

I get that. I’d probably find the largest rubber grommet in the vehicle and run the charge cable through that. It would likely be under the rear seats or at near the very rear of the vehicle.

Is NMC better under cold temps than LFP?

NMC is better in the cold.
At -20 C, capacity fade is about:
NMC: <30%
LFP: 40-50%

LFP also experiences longer-term degradation if they undergo deep discharges in the cold.
And LFP should not be charged at a high charge rate when cold. They should be charged at no more than 0.2-0.3C (3-5 hours from 0% to 98%, not counting the slow balancing time spent from 98% to 100%).

However, LFP has better high-temperature performance, including lower likelihood of runaway overheating. LFP also has more cycles (2k-5k) than NMC (about 2k). LFP also allows higher charge rates, when it’s not cold—if it’s cold, LFP should be charged at no more than about 0.2-0.3C (3-5 hours to full).

 

[Logan]

You lost me at look at my hammock in the snow. I remember when my son was in Scouts he got his penguin patch for sleeping in the snow. . No thanks. Glamping. I’m all for glamping.

Guilty. Former Scout here.

If it helps, its got an underquilt (like the bottom half of a sleeping bag) with a few inches of down insulation in it under the hammock. So, its not a cold nights sleep at all. The weirdest part, was waking up when they were doing avalanche control on the other side of the mountain. Waking up to big bombs going off in the otherwise silence of the snow, is pretty bizzare .

Usually when we go out, we make snow caves, or igloos. Those just take soooo much longer to make. The hammock is for when I want to camp with low effort, or just don't want to get wet (like the year my snow pants split, so I only had my sleeping gear to wear, which isn't really designed for "digging snow caves").

Yeah, I can think of myriad ways for any kind of automated or manual option to fail. But at least a manual option, that reset every time the vehicle is restarted, might place the responsibility on a human taking a positive action to engage the engine rather than a piece of software or a company.



I get that. I’d probably find the largest rubber grommet in the vehicle and run the charge cable through that. It would likely be under the rear seats or at near the very rear of the vehicle.



NMC is better in the cold.
At -20 C, capacity fade is about:
NMC: <30%
LFP: 40-50%

LFP also experiences longer-term degradation if they undergo deep discharges in the cold.
And LFP should not be charged at a high charge rate when cold. They should be charged at no more than 0.2-0.3C (3-5 hours from 0% to 98%, not counting the slow balancing time spent from 98% to 100%).

However, LFP has better high-temperature performance, including lower likelihood of runaway overheating. LFP also has more cycles (2k-5k) than NMC (about 2k). LFP also allows higher charge rates, when it’s not cold—if it’s cold, LFP should be charged at no more than about 0.2-0.3C (3-5 hours to full).

Some of this I was aware of (LFP having more charge cycles, and less risk of thermal runaway), but wasn't aware that NMC seems to do better in the cold.

And for those reading along, this gets interesting because the BEV is NMC, and the Harvester is LFP.

 

[cyure]

Guilty. Former Scout here.

If it helps, its got an underquilt (like the bottom half of a sleeping bag) with a few inches of down insulation in it under the hammock. So, its not a cold nights sleep at all. The weirdest part, was waking up when they were doing avalanche control on the other side of the mountain. Waking up to big bombs going off in the otherwise silence of the snow, is pretty bizzare .

Usually when we go out, we make snow caves, or igloos. Those just take soooo much longer to make. The hammock is for when I want to camp with low effort, or just don't want to get wet (like the year my snow pants split, so I only had my sleeping gear to wear, which isn't really designed for "digging snow caves").

Some of this I was aware of (LFP having more charge cycles, and less risk of thermal runaway), but wasn't aware that NMC seems to do better in the cold.

And for those reading along, this gets interesting because the BEV is NMC, and the Harvester is LFP.

You are talking to the woman who ordered Dominos pizza to the Scout camp parking lot because I just couldn’t eat one more day of camp food.

 

[Logan]

You are talking to the woman who ordered Dominos pizza to the Scout camp parking lot because I just couldn’t eat one more day of camp food.

I'm not even mad.

Well played.

Well played indeed.

 

[cyure]

I'm not even mad.

Well played.

Well played indeed.

Oh I went to all the parents and said who wants pizza. By the time I was done asking I ended up ordering $200 worth of Dominos. That was a lot of Dominos pizza in 2008.